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
Low temperature screen plasma technology, a high plasma density, through using a low energy supply, shows excellent effects on a low alloy chromium-molybdenum steel for plastic molds because it does not show a compoun...Low temperature screen plasma technology, a high plasma density, through using a low energy supply, shows excellent effects on a low alloy chromium-molybdenum steel for plastic molds because it does not show a compound layer and a high surface hardness without a deterioration in matrix hardness. For interest about hardening depth, both the screen plasma nitriding and plasma nitro-carburizing processes were tested including nitrogen, hydrogen and a methane mixed gas environmental at 653 K, 713 K. The optical emission spectroscopy (OES) has been analyzed during screen plasma nitriding (SPN) and a nitro-carburizing process (SPNC) was proceeded at 713 K and the same pressure. I find it difficult to dissociate nitrogen molecules perfectly with neutral nitrogen atoms via the DC-plasma nitriding process. Therefore, the SPN and SPNC process have shown a high density of plasma species even though low temperature plasma conditions have a high peak intensity of Hβ and Hγ in the results of the analysis by OES. The hardness value was measured with the micro-Vickers hardness tester after the SPN, SPNC process and the chemical composition of nitriding layers were traced by GDOES. The screen nitriding layer via the screen plasma technology has shown excellent properties with a thickness depth of about 850 ~ 900 HV without the deterioration of matrix hardness value.展开更多
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.
文摘Low temperature screen plasma technology, a high plasma density, through using a low energy supply, shows excellent effects on a low alloy chromium-molybdenum steel for plastic molds because it does not show a compound layer and a high surface hardness without a deterioration in matrix hardness. For interest about hardening depth, both the screen plasma nitriding and plasma nitro-carburizing processes were tested including nitrogen, hydrogen and a methane mixed gas environmental at 653 K, 713 K. The optical emission spectroscopy (OES) has been analyzed during screen plasma nitriding (SPN) and a nitro-carburizing process (SPNC) was proceeded at 713 K and the same pressure. I find it difficult to dissociate nitrogen molecules perfectly with neutral nitrogen atoms via the DC-plasma nitriding process. Therefore, the SPN and SPNC process have shown a high density of plasma species even though low temperature plasma conditions have a high peak intensity of Hβ and Hγ in the results of the analysis by OES. The hardness value was measured with the micro-Vickers hardness tester after the SPN, SPNC process and the chemical composition of nitriding layers were traced by GDOES. The screen nitriding layer via the screen plasma technology has shown excellent properties with a thickness depth of about 850 ~ 900 HV without the deterioration of matrix hardness value.
