[16p-2Q-1~13] 8.3 deposition of thin film and surface treatment

△ [16p-2Q-11] Investigation and control of non-uniform hardening in atmospheric-pressure plasma nitro-quenching

〇Masaki Mitani¹, Ryuta Ichiki¹, Takashi Inoue¹, Yutaro Iwakiri¹, Shuichi Akamine¹, Seiji Kanazawa¹ (1.Oita Univ.)

Keywords:nitro-quenching,atmospheric-pressure plasma,plasma jet

We have researched surface hardening of low-alloy steel by nitro-quenching using an atmospheric-pressure plasma jet. We have succeeded in producing iron-nitrogen martensite. However, the radial profile of surface hardness was remarkably non-uniform. We consider that such non-uniform hardness profile will be caused by the surface temperature. In this research, we change the treatment temperature to investigate the temperature dependence of hardness profile. As a result, we found that the formation of retained austenite is related to softening of hardened layer. Moreover, we achieved the control of hardness profile by treatment temperature.