Liquid nitriding of Cll0 steel was conducted in a wide range of temperatures （400-670 ℃） using a kind of chemical heat-treatments, and the hardness, mechanical and corrosion properties of the nitrided surface were ...Liquid nitriding of Cll0 steel was conducted in a wide range of temperatures （400-670 ℃） using a kind of chemical heat-treatments, and the hardness, mechanical and corrosion properties of the nitrided surface were evaluated. Experimental results revealed that the microstructure and phase constituents of the nitrided surface alloy are highly depended on the processing condition. When C 110 steel was subjected to liquid nitriding at 430 ℃, the nitrided layer was almost composed of a thin e-Fe2-3N layer. When C 110 steel was subjected to liquid nitriding at 640 ℃, the phase composition of the nitrided layer was greatly changed. The nitrided layer depth increased significantly with increasing the treating temperature. The liquid nitriding effectively improved the surface hardness. After liquid nitriding, the absorption energy of the treated sample decreased and the tensile strength increased by Charpy V-notch （CVN） test. But the elongation of treated sample decreased. The reason is that the nitrided layer of sample is hardened and there is brittlement by diffusion of nitrogen atom. Despite of treatment temperature, the liquid nitriding can improve the corrosion. After being nitrided at 430 ℃, the nitrided layer of the C110 steel was mainly composed by e-Fe2 3N, which has excellent corrosion resistance and high microhardness, the nitrided sample has the best corrosion resistance. After nitriding temperature over 580 ℃, especially at 680 ℃, the sample＇s surface was covered by the thick oxide layer, which has very low hardness and corrosion resistance. So, the corrosion resistance of samples is severely compromised.展开更多
Ferritic nitro-carburizing is one of the most popular surface hardening methods used to improve lifespan of hot work tool steels.Different types of mediums like gas,liquid,plasma and fluidized bed are generally used d...Ferritic nitro-carburizing is one of the most popular surface hardening methods used to improve lifespan of hot work tool steels.Different types of mediums like gas,liquid,plasma and fluidized bed are generally used during ferritic nitro-carburizing process.In this paper,various ferritic nitro-carburizing methods were compared where gas,salt bath and fluidized are used as mediums.AISI H-13 hot work tool steel specimens were treated by using these different methods of nitro-carburizing and their performance was evaluated by using micro-structural and mechanical analysis.Optical microscopy,micro-hardness testing and X-ray stress analyzer were used for specimen characterization.Moreover,pin on disk dry sliding wear tests were performed to compare wear performance of specimens treated with different nitro-carburizing methods.It is perceived that,medium used during nitro-carburizing has significant influence on the final surface properties that can be achieved by ferritic nitro-carburizing.展开更多
基金Projects(51471112,51611130204)supported by the National Natural Science Foundation of China
文摘Liquid nitriding of Cll0 steel was conducted in a wide range of temperatures （400-670 ℃） using a kind of chemical heat-treatments, and the hardness, mechanical and corrosion properties of the nitrided surface were evaluated. Experimental results revealed that the microstructure and phase constituents of the nitrided surface alloy are highly depended on the processing condition. When C 110 steel was subjected to liquid nitriding at 430 ℃, the nitrided layer was almost composed of a thin e-Fe2-3N layer. When C 110 steel was subjected to liquid nitriding at 640 ℃, the phase composition of the nitrided layer was greatly changed. The nitrided layer depth increased significantly with increasing the treating temperature. The liquid nitriding effectively improved the surface hardness. After liquid nitriding, the absorption energy of the treated sample decreased and the tensile strength increased by Charpy V-notch （CVN） test. But the elongation of treated sample decreased. The reason is that the nitrided layer of sample is hardened and there is brittlement by diffusion of nitrogen atom. Despite of treatment temperature, the liquid nitriding can improve the corrosion. After being nitrided at 430 ℃, the nitrided layer of the C110 steel was mainly composed by e-Fe2 3N, which has excellent corrosion resistance and high microhardness, the nitrided sample has the best corrosion resistance. After nitriding temperature over 580 ℃, especially at 680 ℃, the sample＇s surface was covered by the thick oxide layer, which has very low hardness and corrosion resistance. So, the corrosion resistance of samples is severely compromised.
文摘Ferritic nitro-carburizing is one of the most popular surface hardening methods used to improve lifespan of hot work tool steels.Different types of mediums like gas,liquid,plasma and fluidized bed are generally used during ferritic nitro-carburizing process.In this paper,various ferritic nitro-carburizing methods were compared where gas,salt bath and fluidized are used as mediums.AISI H-13 hot work tool steel specimens were treated by using these different methods of nitro-carburizing and their performance was evaluated by using micro-structural and mechanical analysis.Optical microscopy,micro-hardness testing and X-ray stress analyzer were used for specimen characterization.Moreover,pin on disk dry sliding wear tests were performed to compare wear performance of specimens treated with different nitro-carburizing methods.It is perceived that,medium used during nitro-carburizing has significant influence on the final surface properties that can be achieved by ferritic nitro-carburizing.
