Chuji Kagaya

Development of Solid Nitriding Method Using Thermosetting Waste Plastic

In recent years, global warming and resource exhaustion problems require the manufacturers to minimize substances of environmental concern and industrial wastes and adopt measures for expedited recycling. As a result, making effective use of wastes to try for further energy conservation and high quality products is an important assignment in the heat treatment and surface hardening treatment fields as well. This study has investigated the effectiveness of waste melamine resin in solid nitriding of JIS SUS304 austenitic stainless steel plate. After heating the stainless plate in waste melamine resin fragments and cooling in air, the surface was analyzed. It was found that a nitrided layer had formed on the surface of the plate, and the nitriding potential of waste melamine was shown to be high. It is therefore likely that this method can be effectively applied to the development of economically advantageous high-performance materials and value-added products.

Impact properties of the weld interface in SCM415/SCM415 friction welded butt joints

Summary Instrumented Charpy impact testing was carried out at various temperatures from −196 °C to 200 °C in order to clarify the absorbed energies, impact values, transition temperatures and fracture behaviour at the weld interface of SCM415/SCM415 friction welded joints; the results were examined and compared with the impact properties of the base metal. The results may be summarised as follows: The impact energy transition curve of the weld interface in the transition region shifted to the lower temperature side in comparison with that of the base metal. The impact energy transition temperature was approximately 30 °C at the weld interface and approximately 57 °C for the base metal; these temperatures were consistent with the temperatures estimated from the impact fracture surface. Resistance to crack initiation at the weld interface in the transition region increased markedly in comparison with that of the base metal. Impact resistance at the weld interface under the friction welding conditions employ...

Impact resistance of steel partially prevented from liquid nitriding by inorganic coating

The purpose of this paper is to investigate the effectiveness of an inorganic coating to prevent partial embrittlement or decrease in impact resistance. Charpy impact tests have been carried out, with the use of preventively coated specimens from liquid nitriding for various treatment times. The impact value and the fracture surface are discussed by comparing them with both nitrided and non-nitrided specimens. The results show that this method may be used as practical technique for partial prevention of liquid nitriding.

Mask-coating using inorganic agent for chemical vapor deposition treatment.

Mask-Coating Using Inorganic Agent for Chemical Vapor Deposition Treatment by Chuji KAGAYA*, Masanori KATO*, Noboru EGAMI** and Masaru IKENAGA*** Chemical vapor deposition (CVD) method is used to deposit hard wear resistant materials such as titanium carbide and nitride onto a substrate. A suitable masking agent for CVD has not yet been developed at present, however. The purpose of this paper was to investigate the possible utilization of inorganic agents for such mask-coating. Both of the portion pre-coated with an inorganic agent and the un-precoated portion have been examined by means of X-ray diffraction analysis, hardness tests and structure observations. The characteristics of the inorganic mask-coating agent were also investigated by differential thermal analysis and gas chromatography. The experimental results showed that masking was successful with this agent. This coating was thermally as well as chemically stable and can be used as a masking agent for the CVD treatment. キー ・ワー ド:無 機 質 コー テ ィ ン グ剤,CVDマ ス キ ン グ剤,示 差 熱 曲 線,分 解 ガス