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DOI： 10.11279/jfes.91.512

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J-GLOBAL

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Publishing type：Research paper (scientific journal)  

This study specifically examined a method using fluidity test results to measure the interfacial heat transfer coefficient (IHTC) between a molten alloy and a mold during flow. Review of earlier studies revealed that conventional methods require the choking area length to calculate the IHTC during flow, but one earlier study used an assumed choking area length. Details of its length remain unclear. Using an arbitrarily chosen choking area length leads to inaccurate acquisition of the IHTC. For this study, we observed the microstructures and macrostructures around a fluidity test specimen tip to ascertain the choking area length. This value led to calculation of the IHTC between the flowing bronze melt and the shell sand mold as 1521 W/m2•K. This study also found a new method requiring no choking area length to ascertain the IHTC between the flowing melt and the sand mold. The IHTC obtained using this method was 1406 W/m2•K, representing a difference of about 8% from the value obtained using a conventional method. This study assessed experimental conditions under which the new method can produce accurate IHTC values.

DOI： 10.1016/j.jmatprotec.2019.116394

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J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Plasma nitriding is used for materials that are challenging to nitride by conventional techniques. Because of the sputtering effect of positive ions during glow discharge, protective oxide films on the surfaces of materials including stainless steels, aluminum alloys, and titanium alloys, can be effectively removed by ion and energetic particle bombardment; thus, nitrogen mass transfer from the plasma into the component subsurface can be achieved effectively. Plasma nitriding therefore has potential applicability to treat high-entropy alloys (HEAs) containing large amounts of strong oxide-forming elements such as chromium. In this study, the effects of plasma nitriding were investigated on the microstructural, mechanical, and corrosion properties of a CoCrFeMnNi HEA with an fcc structure that is soft and ductile. The HEA was produced by melting pure metals and casting. Direct-current plasma nitriding was then performed in a gas mixture of 25% N-2 and 75% H-2 for 54 ks at 673-823 K under 200 Pa with an auxiliary cathodic screen. After nitriding, the nitrided samples were examined using scanning electron microscopy, X-ray diffraction (XRD), Vickers microhardness testing, electron probe micro-analysis, and glow discharge optical emission spectroscopy (GD-OES). After nitriding, GD-OES revealed that the thickness of the nitriding layer tended to increase with increasing nitriding temperature. XRD analysis revealed that an fcc supersaturated solid solution phase was formed on surfaces nitrided below 723 K, whereas a CrN phase was formed on those nitrided above 723 K. The Vickers microhardness of the nitrided sample surfaces reached approximately 1300 HV. Ball-on-disk wear tests revealed that the wear loss of nitrided samples was considerably lower than that for untreated samples. Finally, the pitting corrosion resistance of samples nitrided at 673 K was higher than that of untreated samples.

DOI： 10.1016/j.surfcoat.2018.06.088

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DOI： 10.1007/s40962-018-00292-y

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DOI： 10.1007/s40962-019-00310-7

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/materia.58.86

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Institute of Metals (JIM)  

We aimed to understand the corrosion behavior of Pb free Cu alloys Japan Industrial Standards JIS CAC411 and CAC901 and the substances Cu2S and Bi, respectively, which are in the alloys as particles, in a 3.0 mass NaCl aqueous solution. The corrosion behavior of the Pb-free Cu alloys and the substances were compared with those of a Cu alloy JIS CAC406, which Pb detected as crystallized particles in it, and a Cu alloy JIS CAC403 without any crystallized substances. Cu2S specimens were produced by sintering Cu2S powders. Bi specimens were produced by Bi electro plating on Cu plates. The measured corrosion potentials of CAC411, CAC901, and CAC403 were close to that of Sn instead of Cu. The anodic polarization curves of all the Cu alloy specimens showed that the anodic current density increased rapidly at a potential above-0.20 V vs. Ag/AgCl, and the rapid increase in the current density was similar to that of Cu. Therefore, it was concluded that the increase in the current density of the Cu alloys results from the dissolution of Cu in a matrix. Cu2S was converted into CuS during the anodic reaction. However, the corrosion potential of Cu2S was higher than those of Cu and CAC411. Therefore, it was concluded that the Cu2S particles in CAC411 act as cathodic sites and remain stable during the natural corrosion. The corrosion potential of Bi was higher than that of CAC901 and slightly lower than that of Cu. At the potentials below-0.10 V vs. Ag/AgCl, Bi was thought to be covered with a passive Bi2O3 film and the passive film was expected to protect Bi from corrosion. Therefore, it was concluded that the Bi particles in CAC901 hardly suffer severe corrosion. The corrosion potential of Pb was lower than those of the Cu and Cu alloys, expect for CAC406. In addition, Pb exhibited a large anodic current density and dissolved actively around the corrosion potential of Cu. Therefore, it was concluded that the Pb particles dissolved preferentially during the corrosion of CAC406 owing to galvanic corrosion. Finally, it was concluded that the Cu2S and the Bi particles in CAC411 and CAC901, respectively, hardly suffer severe corrosion compared with the Pb particles in CAC406 in chloride-containing aqueous solutions such as sea water. c 2018 The Japan Institute of Metals and Materials.

DOI： 10.2320/jinstmet.J2018034

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J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Institute of Metals (JIM)  

AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA) ingots were successfully obtained by high-frequency melting and centrifugal metal- mold casting under an Ar flow. The microstructure of the ingots was investigated by trans-scale observations using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The constituent phases of the ingots were identified as fcc and bcc phases by X-ray diffraction (XRD) analysis, and were not dependent on the position of the ingot. The microstructure was observed to have a primary fcc dendrite and fcc+bcc eutectic structure at the inter- dendrite region, regardless of the position of the ingots. The size of the solidification structure was affected by the cooling rate. Faster cooling rates resulted in finer solidification structures. TEM observations clarified the development of L12 ordering structures in the primary fcc dendrite phase, while the ordering peak could not be detected by XRD analysis.

DOI： 10.2320/matertrans.F-M2017851

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Language：Japanese   Publisher：Japan Foundry Engineering Society  

<p>  AlCoCrFeNi_2.1 eutectic high entropy alloy (HEA) ingots were successfully obtained by high-frequency melting and centrifugal metallic mold casting under Ar flow. The microstructure of the ingots was investigated by trans-scale observations using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The constituent phases of the ingots were identified as fcc and bcc phases by X-ray diffraction (XRD) analysis, and were not dependent on the position of the ingots. In particular, dendrite fcc and inter-dendrite fcc and bcc eutectic structures were observed, regardless the position of the ingots. The solidification structure was affected by cooling. Faster cooling rates resulted in finer solidification structures. TEM observations clarified the development of L1₂ ordering structures in the dendrite fcc phase, while the ordering peak could not be detected by XRD analysis.</p>

DOI： 10.11279/jfes.89.119

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER INTERNATIONAL PUBLISHING AG  

Molten metal filling rate and polystyrene foam pattern decomposition were examined in order to clarify how to improve the metal flow length of cast iron in the evaporative pattern casting process. The molten metal filling rate and the decomposition rate of a polystyrene foam pattern were measured during a casting experiment. A copper alloy was also cast using the same method for the purpose of comparison. The molten metal filling rate of cast iron was lower than that of the copper alloy. The volume of the gas gap increased with increasing melt temperature and decreasing coating permeability. A large amount of liquefied resin was formed by thermal decomposition of the foam pattern. The molten metal filling rate increased with increasing coating permeability and increased further with increasing coating thickness in the final step of molten metal filling. Even with increasing permeability of the coating, there is an occurrence of misruns in the case of molten cast iron, while the use of a thicker coating increased the molten metal flow length.

DOI： 10.1007/s40962-016-0108-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Institute of Metals (JIM)  

In this study, we aimed to understand the corrosion behavior of Pb-free Cu alloys (Japan Industrial Standards (JIS) CAC411 and CAC901) and their crystallized substances (Cu2S and Bi, respectively) particles in a 3.0 mass% NaCl aqueous solution, in comparison with those of a Cu alloy (JIS CAC406), its crystallized substance (Pb) particles. and a Cu alloy (JIS CAC403) with no crystallized substances. A Cu2S specimen was produced via sintering Cu2S powders, and a Bi specimen was produced by Bi electro-plating on a Cu substrate. The measured corrosion potentials of CAC411, CAC901, and CAC403 were close to that of Sn instead Cu. The current density peak near the corrosion potential of CAC403, which was the highest Sn concentration, was the largest in comparison with those of the other Cu alloys. Conversely, rapid increase in the current density, which was shown for all the Cu alloy at the potential above -0.20 V vs. Ag/AgCl, was similar to that of Cu. Therefore, it was concluded that these increase in current densities of Cu alloys was due to the dissolution of the Cu matrix. Cu2S was converted into CuS during the anodic reaction. However, the corrosion potential of Cu2S was higher than those of Cu and CAC411. Therefore, it was concluded that the Cu2S particles in CAC411 act as cathodic sites and remain stable during the natural corrosion. The corrosion potential of Bi was higher than that of CAC901 and slightly lower than that of Cu. Further, at the potentials below -0.10 V vs. Ag/AgCl, Bi was thought to be covered with the passive film of Bi2O3 that was expected to protect Bi from corrosion. Therefore, it was concluded that the Bi particles in CAC901 hardly suffer severe corrosion. The corrosion potential of Pb was lower than those of the Cu and Cu alloys expect for CAC406. In addition, Pb exhibited a large anodic current density and dissolved actively around the corrosion potential of Cu. Therefore, it was concluded that the Pb particles dissolved preferentially during the corrosion of CAC406 owing to the galvanic corrosion. It was finally concluded that the Cu2S and the Bi particles in CAC411 and CAC901, respectively, hardly suffer severe corrosion than the Pb particles in CAC406 in chloride-containing aqueous solutions like sea water.

DOI： 10.2320/matertrans.M2017196

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Language：Japanese   Publisher：Japan Foundry Engineering Society  

Lead-free bronze castings dispersed with sulfide particles, whose main composition is the same as JIS CAC411, and which contains over 0.05mass% phosphorus as a residual element, were prepared. Tensile test, fluidity test, microstructure test and pressure toughness test of the lead-free bronze castings were carried out. Results of the tensile tests for JIS CAC406 castings, which are used as common bronze castings, show that the elongation of some specimens containing over 0.05 mass% phosphorus is below the JIS requirement of 15%. In contrast, the elongation of the lead-free bronze castings dispersed dispersed with sulfide particles was over 15% even phosphorus content was increased to about 0.1mass%. Increasing the phosphorus content improves the fluidity of the lead-free bronze castings and realizes excellent pressure toughness. In addition, the results of measurement of elemental distribution by EPMA reveal the presence of regions composed of phosphorus and nickel. This suggests that a certain amount of phosphorus exist as a compound composing of phosphorus and nickel.

DOI： 10.11279/jfes.87.849

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CiNii Books

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Language：Japanese   Publisher：Japan Foundry Engineering Society  

Correlation relationships between graphite nodule count evaluated by casting experiment and equilibrium amount of chemical compounds calculated by thermodynamic calculation were investigated for clarifying effect of graphite nodule count on amount and formation temperature of nuclear products for graphite nucleation in spheroidal graphite cast iron melt. Graphite nodule counts of spheroidal graphite cast iron varied in additive amounts of calcium, aluminum and sulfur were measured. Equilibrium phases in the cast iron melt with same chemical compositions were calculated in a condition at 1150℃ without graphite crystallization. Calculated melting points of oxysulfdie in which is composed mostly of sulfides was higher than temperature of spheroidizing treatment. It is suggested that the oxysulfide is suspended in the melt before pouring. Magnesium nitride was stable in temperature below 1300℃-1350℃, and in a case that aluminum content was increased to about 0.02mass%, aluminum nitride was stable in temperature below 1300℃-1380℃. There is negative correlation between the graphite nodule count and the amount of aluminum nitride although there are no correlation relationships between graphite nodule count and formation temperature and amount of the oxysulfide, magnesium oxide and magnesium nitride.

DOI： 10.11279/jfes.86.858

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Temperature of solution heat treatment and aging heat treatment of Cu-Zn-Ni-Mn-Pb alloy were investigated by thermodynamics calculation, microstructural analysis and evaluation of hardness. Solution heat treatment temperature is 700℃. β’phase is precipitated by aging heat treatment at 500℃ and 400℃. Phase boundary between β phase and β’ phase was estimated by thermodynamics calculation. Hardness of the alloy decreases with increasing aging time just after starting aging heat treatment, and increases with increasing aging time after 1h in the case of 500℃ and 2h in the case of 400℃.

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Other Link： http://hdl.handle.net/10112/10559

Language：Japanese   Publisher：Japan Foundry Engineering Society  

<p>  The sulfide morphology in Cu-Sn-Zn-S alloy castings was investigated to understand the transition from eutectic solidification to monotectic solidification. The sulfide morphology was observed to clarify whether sulfides were formed by eutectic reaction or monotectic reaction. The cooling rate during solidification was changed by changing mold materials, mold shapes, and mold sizes. The holding time from deoxidation of melt to casting was changed to understand the effect of deoxidation on the sulfide morphology. Eutectic sulfides were formed when the melt was cooled slowly, and the amount of monotectic sulfide increased with increasing cooling rate. The transition from eutectic morphology to monotectic morphology occurred at cooling rates of 0.5K/s to 1.0K/s. Just after deoxidation with Cu-P alloys, sulfides were formed by monotectic reaction. However, with increasing holding time of the melt after deoxidation, the amount of the sulfides formed by eutectic reaction increased.</p>

DOI： 10.11279/jfes.86.26

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Language：Japanese   Publisher：Japan Thermal Spray Society  

Adhesive strength of zinc alloy sprayed coatings on an annealed steel substrate after girt blasting was measured to understand an effect of work hardening of a substrate surface on adhesive strength between the substrate and the sprayed coatings. The annealed substrate was prepared by heat treatment in reduced atmosphere. The sprayed coatings were prepared by a wire flame spraying process. Degree of work hardening of the substrate was changed by changing blasting time. In the case without annealing, the hardness of the blasted substrate increases with increasing blasting time, and the adhesion increases with increasing hardness of the blasted substrate surface. In the case with annealing, the hardness of the blasted substrate is same as the hardness before blasting. Nevertheless, the adhesion is almost same as the case without annealing. There are no effects of work hardening of the steel substrate surface on the adhesion of the zinc alloy sprayed coatings.

DOI： 10.11330/jtss.50.64

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Language：Japanese   Publisher：Japan Foundry Engineering Society  

The applicability of the permanent mold casting process for the lead free bronze with dispersed sulfide was evaluated with comparison of other conventional copper alloys, such as the leaded bronze, the leaded brass, the lead free bronze including bismuth. The copper alloys were cast into the permanent mold for the solidification cracking test. The relationship between the degree of cracking and the range of the solidification temperature was examined.The lead free bronze with dispersed sulfide was more unbreakable than the other copper alloys. The smaller solidification temperature range, the harder the solidification cracking occurred. In the lead free bronze with dispersed sulfide, there were differences of the dendrite form near by the fracture and the distribution of the residual melt segregated at a part of the end of the solidification. The lead free bronze may have a solidification form being unlikely to crack, and it is possible to apply the permanent mold castings process rather than the other copper alloys. The applicability is almost same as brass castings.

DOI： 10.11279/jfes.84.383

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Language：English   Publisher：Kansai University  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

The influence of the zinc sulfide ratio in the sulfide particle in the lead free bronze castings on the machinability is studied. Also, the influence of alloying elements of the zinc sulfide ratio of the sulfide particle is studied for understanding the mechanism of the zinc sulfide formation during the solidification. The zinc sulfide ratio is evaluated with the analysis of the microstructure in the lead free bronze prepared by the sand mold casting. The condition in which the zinc sulfide stably exists during the solidification is estimated with thermodynamic calculation. The machinability is improved with the decrement of the zinc sulfide ratio. The sulfide is formed as the copper sulfide and the zinc sulfide through eutectic reaction, and also appears as the liquid phase through monotectic reaction. The zinc sulfide is formed with the copper sulfide at the temperature, at which the zinc sulfide was predicted lobe unstable by the thermodynamic calculation. The ratio of the zinc sulfide increases with increasing zinc content. Tin does not affect the zinc sulfide ratio when the tin content is less than about 4 mass%. There is no effect of nickel on the zinc sulfide ratio. [doi:10.2320/matertrans.F-M2011835]

DOI： 10.2320/matertrans.F-M2011835

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELECTROCHEMICAL SOC INC  

This paper aims at quantifying the wettability of the solid carbon fuel by the molten carbonate in a Direct Carbon Fuel Cell (DCFC), to understand its effect on DCFC performance. The wetting behavior of carbon (graphite) under different conditions is observed and analyzed. Direct observation and the time evolution of open circuit potentials (OCP) measured in this work suggest that the wetting phenomena are driven not only by capillary forces but also by the electrochemistry of the reverse Boudouard reaction. A semi-quantitative model is proposed to explain the wetting dynamics of carbon. It shows that the progress of wetting is determined primarily by the production of CO at the carbon surface due to the reverse Boudouard reaction, and the OCP is therefore determined by the rate of the reverse Boudouard reaction as well as the mass transfer limitation of CO removal from the electrode. Consequently, the OCP is a function of operating temperature, ambient gas composition, and the immersed length of carbon electrode. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.022210jes] All rights reserved.

DOI： 10.1149/2.022210jes

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Language：English   Publishing type：Research paper (international conference proceedings)  

The influence of the zinc sulfide ratio in the sulfide particle in the lead free bronze castings on the machinability is studied. Also, the influence of alloying elements of the zinc sulfide ratio of the sulfide particle is studied for understanding the mechanism of the zinc sulfide formation during the solidification. The zinc sulfide ratio is evaluated with the analysis of the microstructure in the lead free bronze prepared by the sand mold casting. The condition in which the zinc sulfide stably exists during the solidification is estimated with thermodynamic calculation. The machinability is improved with the decrement of the zinc sulfide ratio. The sulfide is formed as the copper sulfide and the zinc sulfide through eutectic reaction, and also appears as the liquid phase through monotectic reaction. The zinc sulfide is formed with the copper sulfide at the temperature, at which the zinc sulfide was predicted to be unstable by the thermodynamic calculation. The ratio of the zinc sulfide increases with increasing zinc content. Tin does not affect the zinc sulfide ratio when the tin content is less than about 4 mass%. There is no effect of nickel on the zinc sulfide ratio. © 2012 Japan Foundry Engineering Society.

DOI： 10.2320/matertrans.F-M2011835

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Language：Japanese   Publisher：Japan Foundry Engineering Society  

For substitution of lead bronze, the metallic structure control technique using the eutectoid transformation was employed to develop leadfree or low lead copper alloys for bearings. A lot of the lamellar eutectoid structure of the coppertin based intermetallic compound and the copper solid solution containing fine bismuth precipitates were dispersed in ascast alloys by means of the alloy design technique. The lamellar eutectoid structurewas formed between primary α dendrite arms after transformation of a part of β phase without producing granular δ phases. In the range of tin content from 4 to 12 mass%, the amount of the eutectoid structure was linearly increased with the tin content. And above 12 mass%, it was turned to decreasing. The alloy containing of the lamellar eutectoid structure showed higher antiseizing and higher abrasion resistances than those of the lead bronze LBC3. It was considered that the texture of laminate composite and fine bismuth precipitates containing were produced an excellent results to the frictionalwear properties.

DOI： 10.11279/jfes.83.513

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Language：English   Publisher：MANEY PUBLISHING  

DOI： 10.1179/003258911X12959522442673

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Language：English   Publisher：MANEY PUBLISHING  

DOI： 10.1179/003258911X12959522442673

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Hydrogen solubility in molten cupronickel is significantly increased by the presence of Ni. Therefore, gas defects become a major problem. In addition copper alloys to dissolve hydrogen and oxygen while maintaining a certain balance. Therefore, in order to produce a sound casting, it is necessary to remove hydrogen and oxygen are at the same time.So, CaF2 studied the simultaneous treatment with degassing and deoxidation. Shown by the following formula CaF2 deoxidation reaction when using the degassing.CaF2 + O + 2H → CaO + 2HF↑ ………(1)(1) can be performed simultaneously in the reaction of dehydrogenation and deoxidation expression. After dissolving soluble materials, CaF2 completely covered with the molten metal in flux. The lining of a pressure agent graphite Rutsu (Al2O3) in a mixture of CaF2 and attempted to improve the effect of degassing and deoxidation. The results obtained are as follows.CaF2 reduces the amount of gas to cover the defects in the flux of molten metal containing. In addition, the effect showed a tendency to increase the longer the degassing and deoxidation time of flux coating. The lining of the crucible during the drug showed a tendency to improve the effect of CaF2 deoxidation and degassing and mixing.

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CiNii Books

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CiNii Books

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Language：Japanese   Publisher：Kansai University  

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Language：Japanese   Publisher：Kansai University  

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Other Link： http://hdl.handle.net/10112/2806

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ASM INTERNATIONAL  

This article shows the quantitative evaluation of the residual grit on a blasted substrate, and the removability of the residual grit is examined. Carbon steel plates were blasted by white alumina grit with mean diameters of 338 to 1106 mu m. The velocity and the number of grit particles were measured during blasting. The residual grit was removed from a substrate surface by the dissolution of the blasted substrate surface. A mixed acid solution was used as the dissolution solution. The residual grit weight was 7 to 17 g/m(2). The amount of the residual grit and the penetration depth of the embedded grit increased with increasing grit size. The penetration depth was 5 to 9% of the mean diameter of the grit. The residual grit weight and the penetration depth increased with the increase of the momentum of the grit particle.

DOI： 10.1361/105996306X147018

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Language：Japanese   Publisher：日本伸銅協会  

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Other Link： http://hdl.handle.net/10112/1597

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

A 55mass%Al-L5mass%Si-Zn system alloy with good corrosion resistance was sprayed on a plaster substrate. Then, the formation process and some properties of the sprayed coating were investigated. Using the interrupted quenching method, it was found that the sprayed coating structure was not only the layer structure but also a casting structure. Due to large solidification range, the solidification pattern was a mushy type with characteristic of Al-Si-Zn alloys. The maximum temperature and the shrinkage ratio of the sprayed coating decreased as the spray distance increased, due to the decreasing melt particle temperature. Tensile strength and the elongation of the sprayed coating decreased as the spray distance increased, due to an increase in the porosity ratio. In particular, a large amount of oxide was formed in the sprayed coating when air was used as the carrier gas. This oxide formation causes an increase in the shrinkage ratio.

DOI： 10.2320/matertrans.47.1853

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Language：Japanese   Publisher：Japan Foundry Engineering Society  

In the planning of defect prevention for the evaporative pattern casting of cast iron, it is necessary to understand the behavior of expandable pattern during thermal decomposition as well as the melt filling behavior. In this study therefore, the effects of the permeability of the coating of the expandable pattern on its surface shape during thermal decomposition, the surface shape of the molten cast iron and the gas gap thickness were investigated, and the following results were obtained. <br>  Convex height in the surface shape of the expandable pattern during thermal decomposition of expandable pattern and that of molten cast iron increases when the coating permeability is low. The shape of the pattern surface does not always correspond exactly with the shape of the melt surface, and in this case the shape of thermal decomposition gas gap becomes the shape of the convex lens. Further, a low coating permeabilityleads to a larger gas gap thickness. The mean decomposition gas pressure, on the other hand, was found to show a level slightly lower than the melt head, and effect of the permeability of the coating is not significant.

DOI： 10.11279/jfes.78.53

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Sn are added to brass, for example, the high strength brass, to improve its corrosion resistance. An added Sn is dissolved in the alpha and beta phases, without forming new phase in such case. The phase fraction is changed by Sn addition. The conversion equation was presented by Guillet to predict the zinc content corresponding to that in the Cu-Zn binary system alloy, and the parameter used in this equation is called the ”zinc equivalent”. Though the research on the zinc equivalent was studied by many researchers, the effects of the added element quantity, zinc quantity and the cooling rate are not taken into consideration. In this study, Alloys in the Cu-Zn-Sn system with various Sn and Zn contents were cast in molds of various cooling rate, and the effects of Sn content, Zn content and cooling rate on the zinc equivalent are investigated based on thermal analysis and microstructure observations.With an increase in Sn or Zn content, beta phase fraction and the dependence of beta phase fraction on the cooling rate increased. The undercooling of phase transformation from beta to alpha increased with an increase in Sn content. The zinc equivalent of Sn increased with an increase in cooling rate. However, in case of low cooling rate in regardless of quantity of Sn and Zn, the zinc equivalent was a value close to 2.0 shown by Guillet.

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Elements are added to brass to improve its the properties, such as toughness, corrosion resistance and abrasion resistance. An added element is dissolved in the alpha and beta phases, without forming new phase, though the phase fraction does change depending on the added element. The conversion equation was presented by Guillet to predict the zinc content corresponding to that in the Cu-Zn binary system alloy, and the parameter used in this equation is called the ”zinc equivalent”. After his study, many results have been reported by other researchers. Though some reports showed approximate values of zinc equivalent by Guillet, values of zinc equivalent of transition element such as Fe or Ni were different between researchers. The effects of the quantity of added element and the cooling rate are not taken into consideration. In this study, Alloys in the Cu-Zn-Ni system with various Ni and Zn contents were cast in molds of various cooling rate, and the effects of Ni content, Zn content and cooling rate on the zinc equivalent are investigated based on thermal analysis and microstructure observations.In the case where the Ni content was altered from 1 mass% to 3 mass% and zinc content was taken to be a constant of 38 mass%, the dependence of beta phase fraction on the cooling rate increases. The zinc equivalent of Ni was approximately -1.3, even if Ni content was changed.In the case where the Ni content was fixed to 1 mass% and zinc content was changed from 38 mass% to 42 mass%, beta phase fraction increased with an increase in Zn content. The dependence of beta phase fraction on the cooling rate increases. The zinc equivalent of Ni increased with an increase in cooling rate. However, in case of low cooling rate, the zinc equivalent was a value close to -1.3 shown by Guillet.

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The (alpha + beta) brass is used widely. Mechanical properties of the alloy are determined by phase fractions of alpha and beta, and so the microstructure control of alpha/beta phases is important. The primary beta phase is partially transformed to alpha by cooling after solidification. Alloyies with different compositions of (alpha + beta) brass were casted, and the relationship between the cooling rate and the undercooling temperatures of the first beta to alpha transformation besides the area fraction of the beta phase were determined. The temperature of the casts were digitally recorded untill 573K. The cooling curves, differential curves, secondary differential curves, and contribution ratio curves were determined. From these curves the phase transformation temperature was specified. The area fraction of beta phase was determined by image analysis of the cast microstructure. Cooling rates were controlled by using several mold materials. The results were as follows:The temperature at the start of the phase transformation from beta to alpha decreased with the cooling rate, and the undercooling temperature of this transformation increased. This tendency becomes remarkable with high zinc content. The beta phase fraction increases with cooling rate and zinc content. There was a liner relation between the square root of the cooling rate and the beta phase fraction. This tendency was remarkable with a high zinc content.The temperature at the start of the phase transformation from beta to alpha decreased with the cooling rate, and the undercooling temperature of this transformation increased. This tendency becomes remarkable with high zinc content. The beta phase fraction increases with cooling rate and zinc content. There was a liner relation between the square root of the cooling rate and the beta phase fraction. This tendency was remarkable with a high zinc content.

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Elements are added to brass to improve its the properties, such as toughness, corrosion resistance and abrasion resistance. An added element is dissolved in the alpha and beta phases, without forming new phase, though the phase fraction does change depending on the added element. The conversion equation was presented by Guillet to predict the zinc content corresponding to that in the Cu-Zn binary system alloy, and the parameter used in this equation is called the ”zinc equivalent”. Though the zinc equivalent has been used as an index for microstructure control for many years, the effects of the quantityof added element and the cooling rate are not taken into consideration. In this study, the effects of the amount of added element and cooling rate on the zinc equivalent are investigated based on thermal analysis and microstructure observations. Alloys in the Cu-Zn-Si system with various Si and Zn contents were cast. In the case where the Si content was altered, the apparent zinc content calculated by Guillet's conversion equation was taken to be a constant. In this calculation, the zinc equivalent of Si was set to 10, and the obtained results were as follows.When the Si content was changed, the beta phase fraction increased with an increase in the cooling rate. However, no such tendency was found when increasing the Si content. This increase in Si content reduced the predictability of the cooling rate. Although the zinc equivalent of Si increased with an increase in the cooling rate in the case of a low Si amount, it remained constant regardless of the cooling rate in case of a high Si content.When the Si content was fixed, the beta phase fraction increased with an increase in zinc content. In this case, however, the change in the beta phase fraction was almost constant, even when the cooling rate increased. Moreover, the increase in zinc content raised the silicon's zinc equivalence. However, the zinc equivalent of Si did not actually change, even when the cooling rate increased. In this experiment, zinc equivalent of Si was less than 10 in all samples.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

We investigate flame spraying of pure aluminum and pure zinc powders on various different substrates and study shrinkage properties and thermal analysis curves of sprayed coatings during the forming process. We also examined effects of the spray distance on the porosity, tensile strength and hardness of sprayed coatings, and obtained the following results. With an increase in spray distance, shrinkage of the sprayed coating and the maximum temperature in the thermal analysis curve decrease. When the cooling ability of the substrate is higher, the shrinkage ratio and the maximum temperature become decrease. The porosity and the hardness of a sprayed coating increase with an increase in spray distance. This occurs because with the increase in the spray distance, the temperature of the sprayed particles decreases, the amount of air taken in the spray increases and, as a result, the cooling rate of the coating increases. The tensile strength of a pure aluminum coating decreases with an increase in spray distance due to the introduction of pores. On the contrary, the tensile strength of a pure zinc coating increases with an increase in spray distance. This occurs because when the spray distance is short, coating temperature is high and, as a result, a large quantity of zinc oxide is formed.

Web of Science

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

We investigated thermal decomposition behavior of expanded patterns including thermal decomposition accelerators such as Ni, NiO, CuO and Cu2O (hereinafter referred to as "powder-blended expanded patterns") in an aluminum alloy evaporative pattern casting process; the following results were obtained. When these metal or metal oxide powders were blended in EPS (expandable polystyrene) patterns, an exothermic reaction occurred between metal or metal oxide powder and aluminum alloy melt. This reaction prevented, temperature drop at the top of the melt flow. In addition, these kinds of powder accelerated pattern thermal decomposition. As a result, the pattern thermal decomposition gas volume increased and aluminum alloy melt filling decreased.

Web of Science

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

Metal or alloy powder capable of exothermic reaction with cast iron melt was blended into expandable polystyrene patterns. The behavior of thermal decomposition of the expandable patterns in evaporative pattern casting of cast iron was investigated. In evaporative pattern casting in which patterns including blended powder of metallic Si, Fe-Si alloy, Fe-Si-Mg alloy, or Fe-Si-Ca alloy were used, the temperature of the melt was higher than that in casting with original non-blended patterns. When the blending ratio was increased, the volume and pressure of decomposition gas during casting process were increased and, on the other hand, the filling rate of the melt was reduced. The use of patterns blended with powder caused no defect and abnormal structure in castings. These results imply that blending of metal or alloy powder into a pattern accelerates thermal decomposition of the pattern.

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Language：Japanese  

The melting of the lead free free-cutting brass in which the fine graphite particle dispersed was tried, and the alloy was cast in the permanent mold. The hot direct and indirect extrusion were carried out for the casting billet. Results of structure and machinabillity of obtained extrusion lots are as follows. (1) The creak of ”a check” had occurred on the surface of the lot in the direct extrusion. It was known that graphite particles coheres and enriches by the plastic flow of the alloy in the ring on the lot circumference. (2) On the indirect extrusion, the tendency in which the graphite particle reversely cohered in center part on lot cross section was recognized. (3) It was known that the distribution density of graphite particle at the lot greatly influenced machinabillity.

CiNii Books

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Zinc quantity on Cu-Zn-Ti alloy was made to change within 25 to 40 mass% in the alloy. The fine graphite particle was agitated and added in the alloy melt. The results were as follows. The graphite area fraction was almost fixed regardless of the zinc content, even if the zinc content change, when the vapor pressure of zinc was fixed. The graphite particle adhered and caught to the zinc vapor bubble when the vapor pressure of zinc rises. It was guessed that the graphite particle surface and separate from melt because of this phenomenon. The formation mechanism of the zinc vapor bubble was considered as following. The cavitation occur behind the impeller when Cu-Zn alloy melt is stirred with the impeller, and the small bubble forms in the cavitation. Therefore, the small bubble grew into large by gathering and uniting.

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Language：Japanese  

Free cutting brass containing lead has excellent machinability. However, the intake of the lead is harmful to the human body. Therefore development of lead free material is required. Lead free brasses containing silicon system intermetallic compound were cast and were examined machinability. The results were as follows. Lead free brasses as Cu-Zn-Mg-Si alloy and Cu-Zn-Mg-Si-Mn alloy were cast. The intermetallic compound of Cu5Mg2Si formed in Cu-Zn-Mg-Si alloy during solidification and after solidification. Beta phase fraction in matrix structure increase with addition of Mg and Si. The quantity of the compound increase with increasing contents of Mg and Si. Form of the compound became like eutectic structure when Mg and Si contents were too much. Because of addition of Mg and Si to brass, chip size became small and hardness increased. Chips curl up in small pieces. When copper content increase, alpha phase fraction increased and intermetallic compound of Cu5Mg2Si was distributed on boundary of alpha and beta phase. Furthermore, eutectic structure did not form even if contents of Mg and Si were much. In this case, chip size became more small and the hardness decrease.When manganese was added to Cu-Zn-Mg-Si alloy, Mn5Si3 formed. The compound uniformly dispersed. Chip size of Cu-Zn-Mg-Si-Mn alloy was smaller than that of Cu-Zn-Mg-Si alloy.

CiNii Books

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

Intake of lead is harmful to the human body. Therefore, it is necessary to substitute other alloying elements for lead in Cu alloys. Using a Cu-9.5 mass%Sn alloy powder and CaF2, which has sliding properties equal to lead, a composite sprayed coating (by flame spraying) was developed. The results were as follows. A composite sprayed coating with the desired characteristics was successfully produced. The area fraction of the CaF2 layer in the composite coating increased with the increase in the blend ratio of CaF2 in the blended powder. The wear resistance of the composite coating containing CaF2 was excellent. As a result it was determined that CaF2 in the composite coating was effective as a sliding material substitute for lead.

Web of Science

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Language：Japanese   Publisher：Kansai University  

The Carbon pickup phenomenon in the evaporative pattern casting process was investigated using hypoeutectic cast iron, spheroidal graphite cast iron, cast steel and high chromium cast iron as the Fe-C system alloys. The carbon pickup phenomenon occurred due to the thermal decomposition products in the front of the melt flow. When the distance of the melt flowed was 100 mm, the carbon pickup ratio of hypoeutectic cast iron and high chromium cast iron showed almost the maximum value. The carbon pickup ratio rises, as it is smaller for the carbon equivalent of molten cast iron. In particular, the carbon pickup ratio in the cast steel was remarkably high. Conversely, in the molten spheroidal graphite cast iron with the hypereutectic composition the carbon pickup phenomenon did not occur. The carbon pickup ratio increased with an increase in the blended ratio of EPS in the foamed pattern on the hypoeutectic cast iron.

CiNii Books

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Language：Japanese  

Though the adhesion between substrate and sprayed coating seems to be mainly due to the anchoring effect, quantitative examinations have not been sufficient. In this paper, the surface condition of a roughened substrate is quantitatively evaluated using a surface roughness tester, and the adhesive relationship is clarified. Substrate used was S45C carbon steel, and the roughening methods were blasting and endless belt polishing with alumina grit, in various roughening conditions. A pure copper coating was formed using the powder flame spraying method on roughened substrate. The drawing adhesion strength test method was used to evaluate the adhesive properties. The adhesive strength is reduced, though the surface roughness of the substrate increases, as the size of the grid particles for roughening increase. The alumina grits remained on the substrate after roughening, and they were removed by ultrasonic cleaning. Though there is no relation between the adhesive strength and the ratio of the increase in the surface area of substrate due to the roughening treatment, it is recognized that the adhesive strength also increases when the roughness gradient of the substrate increases.

CiNii Books

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

In order to investigate the formation process from delta dendrite to gamma grain in a hypo-peritectic carbon steel, an unidirectionally solidifying carbon steel sample is quenched from a temperature above the solidus temperature. Three zones of primary dendrite, fine columnar grain and coarse columnar grain are observed in the sample. The dendritic zone consists of (L+delta) phase, the fine columnar grain is both phases of (L+delta+gamma) and (delta+gamma), and the coarse columnar grain is gamma phase. The width of the fine columnar grain agrees with the primary arm spacing of the 6 dendrite and it is the same result as that for a hyper-peritectic carbon steel. The gamma grain boundary in the zone of the fine columnar grain forms at the skeleton of the 6 dendrite, while that for a hyper-peritectic carbon steel forms at the position between the 6 dendrites. Since transition from the fine columnar grain to the coarse one occurs immediately after the disappearance of 6 phase, the 6 phase prevents the coarsening of the fine columnar grain. A length of the zone of the fine columnar grain decreases with increasing carbon concentration. The length extends according to the addition of ferrite-stabilizing elements. The extended effect becomes stronger in the sequence of Nb&gt;V&gt;Mo, while Ni as an austenite-stabilizing element have no influence on the length.

Web of Science

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MINERALS, METALS & MATERIALS SOC  

When hypo-peritectic carbon steel is quenched during unidirectional solidification, the region of fine columnar grain is observed. It is classified into two coexisting phases. One is coexisting phases of liquid, delta and gamma in the upper part of the region, and the other is coexisting phases of delta and gamma in the lower part of the region. To form the coexisting part of the three phases means that solidification in this experiment proceeds in non-equilibrium state. The size of the narrow side of one fine columnar grain coincides with the arm spacing of a primary dendrite and this result is the same as the hyper-peritectic carbon steel. However, the boundary of the fine grain in the hypo-peritectic carbon steel is formed in different location from that of the hyper-peritectic carbon steel. The former is formed in the skeleton of the dendrite, while the latter is formed in the interspacing of the dendrite. The region of the fine grain changes suddenly to that of the coarse grain when the delta phase in the coexisting part of two phases disappears completely. Therefore, the delta phase in the hypo-peritectic carbon steel might prevent the growth of gamma grain. In order to recognize it, ferrite formers such as Mo, V and Ni are added in the sample. Then, the longitudinal length of the fine columnar grain extends in the sequence of the no addition, Mo, V and Nb.

Web of Science

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Three binds of solidifying regions, (L+delta), (L+delta+gamma) and (L+ gamma) have been observed in an unidirectional solidified hyper-peritectic steel sample quenched from a temperature above the solidus temperature. The primary delta phase in the (L+delta) region solidifies to a dendritic structure, and the fine columnar gamma grains are exist in the boundary part of the (L+gamma) region near to the (L+delta+gamma). The columnar shape of the fine gamma grains is caused by the shape of delta-dendrite. A transition from the fine gamma grains to coarse columnar gamma grains occurs in the (L+gamma) region when a volume fraction of liquid lowers. The structure of coarse columnar gamma grain have no relation with dendrite structure. The fine columnar gamma grains disappear as a result of growth of coarse columnar gamma grain. The measured temperature ranges for the (L+delta+gamma) region agree with those calculated under a non-equilibrium condition. The end temperatures of peritectic reaction and solidification calculated are somewhat lower than the equilibrium temperatures, and are independent of solidification rate.

Web of Science

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Experiments were done by spraying urea (NH2CONH2) as its pyrolysis gases at the intervals of 5min onto molten iron containing 0.4 mass% Cu at 1600 degrees C under reduced pressure. Ii urea amount per each spraying was more than 0.4g, the molten iron was suddenly splashed and slopped over the top of crucible during the experimental run, so that 0.3g of urea was sprayed in the subsequent experiments. Nitrogen concentration of the molten iron increased with increasing the number of urea spraying and the pressure of gas phase. It was 5 to 8 times higher than the concentration in equilibrium with nitrogen gas.
The following relationships were found between the rate constant (k) of copper evaporation and the pressure (P in Pa) :In the case of urea spraying, log k = -log P - 0.762; without urea spraying, log k = -log P - 0.996. These results show that even in the case of urea spraying the evaporation rate of copper was controlled by mass transfer through gaseous film on the surface of the molten iron. It was concluded that acceleration of copper evaporation by urea spraying may be mainly due to the evaporation as Cu(N-3)(2) which has higher vapor pressure than metallic copper.
The evaporation rate of copper somewhat decreased in the case of the molten iron containing 0.33 mass% C, because some part of urea was probably consumed by the formation of iron cyanide. Sulfur had little influence on the evaporation rate.

Web of Science

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

In order to obtain the fundamental information concerning accelerative evaporation of copper dissolved in molten steel with ammoniacal compound, experiments were done by adding urea onto molten pure copper and high carbon iron containing 0.4% Cu at 1150 to 1450 degrees C under an argon atmosphere.
Evaporated amount of the molten copper increased with the increase of urea amount. At constant urea amount, it increased with increasing temperature at 1150 to 1250 degrees C, while it became constant above 1250 degrees C. Based on the mass balance of evaporated copper to added urea, it was concluded that the molten copper was evaporated as Cu(N-3)(2) and this compound decomposed to liberate copper immediately after evaporation.
In the case of high carbon iron containing 0.4% Cu, iron was preferentially evaporated, so that copper was concentrated in the molten iron. At constant urea amount, evaporated amount of the molten iron increased abruptly with increasing temperature up to 1250 degrees C, while it reached almost constant value at 1250 to 1300 degrees C. After again increasing at 1300 to 1350 degrees C, it remained unchanged above 1350 degrees C. X-ray diffraction analysis showed that the matter entrapped from exhaust gas was composed of graphite, Fe3C and Fe3N. Based on this result and the mass balance, it was concluded that the high carbon iron was evaporated as Fe(CN), below 1300 degrees C and Fe(CN)(2) above 1350 degrees C.

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溶射皮膜の密着性向上のために行う前処理には,一般的にブラスト処理が行われる。しかし,どのようなブラスト条件によって密着性が高くなる基材表面粗さが得られるかについての報告は少ない。そこで本研究では,ブラスト加工条件(ブラスト時間,グリッドサイズなど)を変化させた時の基材表面粗さのパラメータを求め,みがき帯鋼(S45C)基材表面へZn‐15%Al合金を溶射し,形成した溶射皮膜の密着性を押剥がし密着試験装置で評価して,効果的な粗面化条件を検討した。得られた結果を以下に示した。1)ブラスト加工によって粗面化された基材表面粗さの凹凸平均ピーク幅Pw(μm)と十点平均粗さRzjisの比が小さくなると密着性は向上する。2)グリッドサイズが小さくなるほどPw/Rzjisの値は小さくなる。3)ブラスト時間が長くなるほどPw/Rzjisの値は小さくなる傾向が見られた。

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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Language：Japanese  

DOI： 10.2320/materia.58.86

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Language：Japanese   Publisher：産報出版  

CiNii Books

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Language：Japanese   Publisher：日本鋳造協会  

CiNii Books

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Language：Japanese   Publisher：関西大学  

CiNii Books

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Language：Japanese   Publisher：関西大学  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：関西大学  

CiNii Books

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Event date： 2017.10

Venue：秋田市  

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Event date： 2017.10

Venue：秋田市  

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Event date： 2017.10

Venue：秋田市  

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Event date： 2017.10

Venue：秋田市  

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Event date： 2017.10

Venue：秋田市  

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Event date： 2017.9

Venue：秋田市  

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Event date： 2017.9

Venue：秋田市  

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Event date： 2017.9

Venue：秋田市  

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Event date： 2017.9

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Event date： 2017.6

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Event date： 2017

Language：Japanese  

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Event date： 2016.9

Venue：高知市文化プラザ かるぽーと  

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Event date： 2016.9

Venue：高知市文化プラザ かるぽーと  

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Event date： 2016.9

Venue：高知市文化プラザ かるぽーと  

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Event date： 2016.9

Venue：高知市文化プラザ かるぽーと  

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Event date： 2016.8

Venue：Korea Aerospace University Goyang, Korea (韓国，高陽市 )  

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Event date： 2016.8

Venue：Kyoto, Japan  

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Event date： 2016.8

Venue：Kyoto, Japan  

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Event date： 2016.5

Venue：Nagoya, Japan  

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Event date： 2015.12

Venue：Suita, Japan  

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Event date： 2015.11

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Event date： 2015.11

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Event date： 2015.11

Venue：大阪大学（吹田市）  

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Event date： 2015.10

Venue：Hanoi, Vietnam  

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Event date： 2015.10

Venue：室蘭工業大学  

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Event date： 2015.10

Venue：室蘭工業大学  

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Event date： 2015.10

Venue：室蘭工業大学  

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Event date： 2015.10

Venue：室蘭工業大学  

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Event date： 2015.9

Venue：信州大学（松本市）  

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Event date： 2015.6

Venue：Düsseldorf, Germany  

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Event date： 2015.5

Venue：早稲田大学  

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Event date： 2015.5

Venue：早稲田大学  

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Event date： 2015.5

Venue：早稲田大学  

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Event date： 2015.1

Venue：Kansai University  

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Event date： 2014.10

Venue：北九州国際会議場  

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Event date： 2014.6

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Event date： 2014.6

Venue：みやこめっせ(京都市勧業館)  

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Event date： 2014.6

Venue：みやこめっせ(京都市勧業館)  

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Event date： 2014.6

Venue：みやこめっせ(京都市勧業館)  

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Event date： 2013.11

Venue：吹田  

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Event date： 2013.11

Venue：関西大学 千里山キャンパス  

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Event date： 2013.11

Venue：吹田  

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Event date： 2013.11

Venue：関西大学 千里山キャンパス  

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Event date： 2013.11

Venue：吹田  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.10

Venue：高岡  

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Event date： 2013.9

Venue：Muroran  

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Event date： 2013.8

Venue：Suita  

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Event date： 2013.8

Venue：Suita  

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Event date： 2013.8

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Event date： 2013.8

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Event date： 2013.5

Venue：甲府  

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Event date： 2013.5

Venue：甲府  

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Event date： 2013.5

Venue：甲府  

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Event date： 2012.11

Venue：吹田  

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Event date： 2012.11

Venue：吹田  

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Event date： 2012.11

Venue：吹田  

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Event date： 2012.11

Venue：吹田  

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Event date： 2012.10

Venue：盛岡  

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Event date： 2012.10

Venue：盛岡  

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Event date： 2012.10

Venue：盛岡  

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Event date： 2012.10

Venue：盛岡  

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Event date： 2012.9

Venue：東大阪  

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Event date： 2012.8

Venue：Pinang  

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Event date： 2012.8

Venue：Pinang  

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Event date： 2012.8

Venue：Pinang  

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Event date： 2012.8

Venue：Pinang  

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Event date： 2012.5

Venue：名古屋  

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Event date： 2012.5

Venue：名古屋  

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Event date： 2012.5

Venue：名古屋  

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Event date： 2012.5

Venue：名古屋  

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Event date： 2012.5

Venue：名古屋  

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Event date： 2012.5

Venue：Houston  

A method for evaluating the adhesion of metallic thermally sprayed coatings by measuring the electrical resistance of the coating sprayed on a metal substrate was carried out. The thermal sprayed coatings were made of zinc alloy on carbon steel substrates, The electrical resistance levels between the substrates and coatings were evaluated. The electrical resistance increases with increasing measurement time. The larger the rate of increase of the electrical resistance, the lower the adhesive strength. There is a possibility to evaluate qualitatively the adhesion properties.

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Event date： 2012.5

Venue：Houston  

Adhesion properties on the substrate blasted by multi-angle blasting with white alumina grit were examined. The low carbon steel substrates were blasted at two blasting angles (high and low angles) in a multi-angle blasting process. The sprayed coating of zinc alloy was evaluated by an adhesion test. The surface roughness levels after the multi-angle blasting were lower than those in the case of normal blasting. The multi-angle blasting was an effective blasting process to obtain improved adhesive properties. The low blasting angle may have contributed for removing contamination from the substrate surface. The high blasting angle may have contributed for an effective surface roughness to enhance the adhesive properties.

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Event date： 2012.4

Venue：Monterrey  

The leaded bronze, the leaded brass the lead free bronze including bismuth the lead free bronze with sulfide dispersion were cast into the permanent mold for the solidification cracking test The applicability of the permanent mold casting process for bronzes was evaluated with comparison of the range of the solidification temperature. The lead free bronze with sulfide dispersion was more unbreakable than the other copper alloys. There are differences the dendrite form near by the fracture and the distribution of residual melts segregated at a part of the end of the solidification. The lead free bronze with sulfide dispersion may have a solidification form being unlikely to crack. The lead free bronze with sulfide dispersion is possible to apply the permanent mold castings process rather than the other copper alloys, and the applicability is almost same as brass castings.

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Event date： 2011.12

Venue：東大阪  

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Event date： 2011.11

Venue：東大阪  

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Event date： 2011.11

Venue：Gyeongju  

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Event date： 2011.11

Venue：慶州  

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Event date： 2011.10

Venue：松江  

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Event date： 2011.10

Venue：松江  

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Event date： 2011.10

Venue：松江  

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Event date： 2011.10

Venue：松江  

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Event date： 2011.10

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Event date： 2011.9

Venue：Hamburg  

The effect of the hardness in the substrate surface blasted by a grit blasting process on the adhesive strength of Zn-Al sprayed coatings is investigated to find the adhesive strength is improved by work hardening of the substrate surface. The adhesive strength between a substrate of a carbon steel and sprayed coatings of Zn-Al alloy sprayed by a wire flame spraying process is measured. The substrate is roughened by the grit blasting process with white alumina girt in various blasting angles and blasting time. The hardness is measured in around 20 micro-meter depth from the substrate surface. The adhesive strength increases with increasing the hardness even if the surface roughness is almost same. There is the definite correlation between the adhesive strength and the hardness rather than the surface roughness.

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Event date： 2011.9

Venue：東大阪  

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Event date： 2011.7

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Event date： 2011.6 - 2011.7

Venue：Dusseldorf  

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Event date： 2011.6

Venue：Dusseldorf  

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Event date： 2011.6

Venue：大阪  

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Event date： 2011.6

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Event date： 2011.5

Venue：東京  

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Event date： 2011.5

Venue：東京  

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Event date： 2011.5

Venue：東京  

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Event date： 2011.5

Venue：東京  

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Event date： 2010.10

Venue：Hangzhou  

Sulfide was focused on for the substitute substance of lead due to lubricant property of sulfide. The way of dispersion of the sulfide in a matrix had been attempted although sulfide density is too small not to separate from a melt during melting. Some elements are added into copper alloy to decrease sulfur activity for formation of sulfide in copper alloy. Cu-Sn-Zn-S system alloy is cast into sand mold to prepare specimens for investigations of microstructure, casting property, mechanical property and machinability.Sulfide dispersion has been achieved through addition of alloying elements to control sulfur activity in copper melt during solidification. Sulfide formed during solidification after developing primary alpha copper dendrite. The sulfide dispersion was observed in the matrix. The microstructure of the sulfide dispersion was confirmed by optical microscope and SEM. Elemental distribution was also investigated by EDX and WDX. The sulfide is mainly copper sulfide. Few shrinkage cavities were observed as the result of dye penetrant test. Mechanical properties of sand castings were above 195MPa and 15% elongation, which are the required value for conventional bronze castings. Machinability showed almost same as the lead containing castings.

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Event date： 2010.9

Venue：札幌  

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Event date： 2010.9

Venue：札幌  

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Event date： 2010.9

Venue：札幌  

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Event date： 2010.6

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Event date： 2010.5

Venue：Singapore  

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Event date： 2010.5

Venue：東大阪  

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Event date： 2010.5

Venue：東大阪  

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Event date： 2010.5

Venue：東大阪  

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Event date： 2010.3

Venue：神戸  

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Event date： 2009.12

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Event date： 2009.10

Venue：Xi’an  

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Event date： 2009.10

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Event date： 2009.10

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Event date： 2009.10

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Event date： 2009.10

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Event date： 2009.6

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Event date： 2009.6

Venue：Brno  

Lead free copper alloy has been required for particular products, for example, plumbing products, due to harmfulness of lead, and has been developed in many countries. Especially, alloys which contain bismuth have been used as the lead free alloy. However, the properties of the lead free alloy containing bismuth is not enough to provide same properties of conventional copper alloy containing lead. Small deposits of bismuth can be barrier to disperse the alloy. A new type of lead free alloy has been developed to provide allowable properties, such as casting properties, mechanical properties and machinability. Sulfide was focused on for the substitute substance of lead due to lubricant property of sulfide. The way of dispersion of the sulfide in a matrix had been attempted although sulfide density is too small not to separate from a melt during melting. Element additions and controlling sulfur activity had been done to make the sulfide form in castings during solidification. Mechanical properties, casting properties and machinability of the developed alloy were evaluated.Sulfide formed during solidification after developing primary alpha copper dendrite. The sulfide dispersion was observed in the matrix. The microstructure of the sulfide dispersion was confirmed by optical microscope and SEM. Elemental distribution was also investigated by EDX and WDX. The sulfide is mainly copper sulfide. There were few shrinkage cavities due to sulfide dispersion in a part of solidification finish. Mechanical properties of sand castings were above the required value for conventional bronze castings. Machinability showed almost same as the lead containing castings.

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Event date： 2009.5

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Event date： 2009.5

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Event date： 2009.5

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Event date： 2009.3

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Event date： 2009.1

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Event date： 2008.10

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Event date： 2008.10

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Event date： 2008.9

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Event date： 2008.5

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Event date： 2008.5

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Event date： 2008.5

Venue：Atlanta  

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Event date： 2008.5

Venue：Maastricht  

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Event date： 2008.3

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Event date： 2008

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Event date： 2008

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Event date： 2007.12

Venue：神戸商工会議所  

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Event date： 2007.12

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Event date： 2007.12

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Event date： 2007.12

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Event date： 2007.11

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Event date： 2007.10

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Event date： 2007.10

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Event date： 2007.10

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Event date： 2007.5

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Event date： 2007.5

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Event date： 2007.5

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Event date： 2007

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Event date： 2007

Venue：Beijing  

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Event date： 2006.11

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Event date： 2006.10

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Event date： 2006.10

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Event date： 2006.10

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Event date： 2006.5

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Event date： 2006.5

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Event date： 2006.5

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Event date： 2006.5

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Event date： 2006.5

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Event date： 2006.3

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Event date： 2006

Venue：Seattle  

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Event date： 2006

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Event date： 2006

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Event date： 2006

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Event date： 2005.11

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Event date： 2005.10

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Event date： 2005.10

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Event date： 2005.10

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Event date： 2005.10

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Event date： 2005.6

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Event date： 2005.5

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Event date： 2005

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Event date： 2005

Venue：Jeju Island  

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Event date： 2005

Venue：Basel  

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2005

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Event date： 2004.12

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Event date： 2004.9

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Event date： 2004.9

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Event date： 2004.6

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Event date： 2004.4

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Event date： 2004.4

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Event date： 2004

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Event date： 2004

Venue：Osaka  

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Event date： 2004

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Event date： 2004

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Event date： 2004

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Event date： 2004

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Event date： 2003.10

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Event date： 2003.10

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Event date： 2003.5

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Event date： 2003.5

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Event date： 2003.3

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Event date： 2002.10

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Event date： 2002.10

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Event date： 2002.6

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Event date： 2002.5

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Event date： 2002.3

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Event date： 2001.10

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Event date： 2001.10

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Event date： 2001.6

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Event date： 2001.6

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Event date： 2001.4

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Event date： 2001.4

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Event date： 2000.11

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Event date： 2000.9

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Event date： 2000.9

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Event date： 2000.9

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Event date： 2000.8

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Event date： 2000.6

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Event date： 1999.9

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Event date： 1998.9

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Event date： 1998.3

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Event date： 1997.9

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Event date： 1997.3

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Event date： 1995.11

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Venue：オンライン  

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Venue：オンライン  

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Venue：オンライン  

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