Plasma radical nitriding was performed to harden the surface of SCM440 steel for 1-10 h at temperature range of 450-550℃. This process involved the use of NH3 gas instead of N2 gas employed for the well-established p...Plasma radical nitriding was performed to harden the surface of SCM440 steel for 1-10 h at temperature range of 450-550℃. This process involved the use of NH3 gas instead of N2 gas employed for the well-established plasma nitriding method. No compound layer was formed during this process except the experiment carried out at 500℃ for 10 h. The main phase produced in the diffusion zone was identified to be γ＇-Fe4（N, C）. A diffusion depth increased with increasing treatment temperature and time （up to about 250 μm）. The surface hardness of radical nitrided layer was about two times higher than that of the untreated surface. The tensile test was carried out to estimate the mechanical properties of surface-hardened SCM440 steel prepared at various plasma radical nitriding treatment time and temperature. The influence of radical nitriding treatment on the tensile strength of the specimen was found to be insignificant. The highest value of the ultimate tensile strength was obtained in the experiment carried out at 500℃ for 1 h. However, the elongation was greatly affected by the radical nitriding processing parameters. The maximum value of elongation, which is equal to about 18.1%, was also obtained under the condition of 500℃ for 1 h.展开更多
The influence of processing temperatures on the surface characteristics of AISI 204Cu austenitic stainless steel was investigated during a low temperature plasma nitrocarburizing.The resultant layer was a dual-layer s...The influence of processing temperatures on the surface characteristics of AISI 204Cu austenitic stainless steel was investigated during a low temperature plasma nitrocarburizing.The resultant layer was a dual-layer structure,which comprises a N-enriched layer on the top of C-enriched layer.The surface hardness and the layer thickness increase up to about HV 0.05 1000 and 20μm with increasing temperature.The specimen treated at 400°C shows a much enhanced corrosion resistance compared to the untreated steel.A loss in corrosion resistance was observed for specimens treated at temperatures above 430°C due to the formation of Cr2N.展开更多
文摘Plasma radical nitriding was performed to harden the surface of SCM440 steel for 1-10 h at temperature range of 450-550℃. This process involved the use of NH3 gas instead of N2 gas employed for the well-established plasma nitriding method. No compound layer was formed during this process except the experiment carried out at 500℃ for 10 h. The main phase produced in the diffusion zone was identified to be γ＇-Fe4（N, C）. A diffusion depth increased with increasing treatment temperature and time （up to about 250 μm）. The surface hardness of radical nitrided layer was about two times higher than that of the untreated surface. The tensile test was carried out to estimate the mechanical properties of surface-hardened SCM440 steel prepared at various plasma radical nitriding treatment time and temperature. The influence of radical nitriding treatment on the tensile strength of the specimen was found to be insignificant. The highest value of the ultimate tensile strength was obtained in the experiment carried out at 500℃ for 1 h. However, the elongation was greatly affected by the radical nitriding processing parameters. The maximum value of elongation, which is equal to about 18.1%, was also obtained under the condition of 500℃ for 1 h.
基金Project(2011AA192)supported by Dongeui University,Korea
文摘The influence of processing temperatures on the surface characteristics of AISI 204Cu austenitic stainless steel was investigated during a low temperature plasma nitrocarburizing.The resultant layer was a dual-layer structure,which comprises a N-enriched layer on the top of C-enriched layer.The surface hardness and the layer thickness increase up to about HV 0.05 1000 and 20μm with increasing temperature.The specimen treated at 400°C shows a much enhanced corrosion resistance compared to the untreated steel.A loss in corrosion resistance was observed for specimens treated at temperatures above 430°C due to the formation of Cr2N.
