Effect of Carburizing Heat Treatment Condition on Induction Hardening of Medium Carbon Steels

• Main Authors: CHEN, JIE-HONG, 陳玠宏
• Other Authors: LEE, JIING-HERNG
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/485hfc

碩士 === 國立虎尾科技大學 === 材料科學與工程系材料科學與綠色能源工程碩士班 === 107 === In this study, AISI 1045 carbon steel, AISI 4140 alloy steel, AISI 4340 alloy steel three different steel material test bars were subjected to carburizing treatment at different temperatures and then oil quenching at different temperatures. Through a series of experiments to understand high-frequency induction hardening parameters (high-frequency input power, coil moving speed), pre-heat treatment with or without carburizing on steel hardness distribution, hardening depth, microstructure. The experimental results show that the amount of alloying elements of steel will affect the surface hardness. If manganese, nickel and the other alloying elements which can improve the hardenability, the surface hardening ability of the steel material will be improved, and the surface hardness of the steel material after quenching and tempering treatment will be improved. After three kinds of steel materials are quenched and tempered, high- frequency induction hardening treatment is carried out with different high- frequency induction parameters. The slower of the moving speed parameter of the induction coil, the better the surface hardness; the higher of the input power parameter of the high-frequency induction hardening, the larger the surface hardness. Martensitic structure or toorsite structure can be obtained by oil quenching treatment under different carburizing conditions. Among them, higher carburizing temperature with lower oil quenching temperature can get more martensitic structure. The surface hardness of the three steel materials will increase with the carburizing temperature, and the hardness can be obtained by induction hardening. Quenching with the lower oil temperature, the steel material is subjected to induction hardening under the same conditions to obtain higher hardness. If the appropriate input power and the moving speed of the induction coil are used, the carburized steel is further refined in the induction hardened structure. If the appropriate input power and the moving speed of the induction coil are used, the carburized steel material is further refined in induction hardening, and the amount of residual austenite is relatively small, can increase the hardness. It can be observed from the microstructure that the steel material subjected to the carburizing treatment is not only harder in hardness than the non-carburizing treatment, and the effective hardening layer is also larger than the non-carburized steel.