In order to prepare heatresistant inner layer of hot-forging die, plasma spraying, plasma re- melting and plasma spray welding were adopted. Cr3C2 coatings of Ni-Based were prepared respectively with 10%, 20% and 30% ...In order to prepare heatresistant inner layer of hot-forging die, plasma spraying, plasma re- melting and plasma spray welding were adopted. Cr3C2 coatings of Ni-Based were prepared respectively with 10%, 20% and 30% Cr3C2 powder and W6Mo5Cr4V2 substrate. The coating microstructure analysis, the micro-hardness test, and the measurement of thermal parameters of coating were conducted. The experimental results show that the coating has the better thermo-physical property by using plasma spray welding method with the powder ratio of 90% Ni60 and 10% Cr3C2, and by this way the micro-hardness of coating can achieve 1100 HV.展开更多
采用Gleeble热模拟试验机对45Cr4Ni Mo V钢在变形温度1000～1150℃,应变速率0.002～5s-1,最大变形量为55%的条件下进行热模拟压缩试验。采用Poliak EI和Jonas J J等人对θ-σ（θ=dσ/dε为加工硬化率）曲线的描述,建立了45Cr4Ni Mo V...采用Gleeble热模拟试验机对45Cr4Ni Mo V钢在变形温度1000～1150℃,应变速率0.002～5s-1,最大变形量为55%的条件下进行热模拟压缩试验。采用Poliak EI和Jonas J J等人对θ-σ（θ=dσ/dε为加工硬化率）曲线的描述,建立了45Cr4Ni Mo V钢在变形参数范围内的动态回复曲线（DRV）。通过对变形过程中的动态再结晶体积分数XD与应力参数之间的关系拟合,得到了45Cr4Ni Mo V钢在变形参数范围内的动态再结晶体积分数模型为：XD=1-exp-1.29ε-εcε0.5εε2.304εε。展开更多
Characteristic features of austenitic steel grades combine a good corrosion resistance with a low hardness, wear resistance and scratch resistance. An interesting possibility for improving the wear behaviour of these ...Characteristic features of austenitic steel grades combine a good corrosion resistance with a low hardness, wear resistance and scratch resistance. An interesting possibility for improving the wear behaviour of these steels without loss of their corrosion resistance lies in enriching the near surface region with nitrogen. The process of a solution nitriding allows the rise of the solution of nitrogen in the solid phase. On this state nitrogen increases the corrosion resistance and the tribilogical load-bearing capacity. The aim of the study was, to investigate the improvement of the pitting corrosion behaviour by solution nitriding. A special topic was to observe the effect of nitrogen by different molybdenum content. So austenitic stainless steels (18% Cr, 12% Ni, Mo gradation between 0.06 to 3.6%) had been solution nitrided. The samples could be prepared with various surface content of nitrogen from 0.04 to 0.45% with a step-by-step grinding. The susceptibility against pitting corrosion of these samples had been tested by determination of the stable pitting potential in 0.5M and 1M NaCl at 25°C. For the investigated steel composition and the used corrosion system there is no influence of molybdenum on the effectiveness of nitrogen. The influence of nitrogen to all of the determined parameters can be described well by PRE = Cr + 3,3 * Mo + 25 *N. XPS analysis of the sample surfaces support the results of the pitting corrosion tests.Additionally surface investigations with an acid elektolyte (0,1M HC1 + 0,4M NaCl) were performed. In this case the passivation effective nitrogen content increases markedly with rising molybdenum concentration of the steel. Obviously an interaction of Mo and N is connected with a strongly acid electrolyte.展开更多
文摘In order to prepare heatresistant inner layer of hot-forging die, plasma spraying, plasma re- melting and plasma spray welding were adopted. Cr3C2 coatings of Ni-Based were prepared respectively with 10%, 20% and 30% Cr3C2 powder and W6Mo5Cr4V2 substrate. The coating microstructure analysis, the micro-hardness test, and the measurement of thermal parameters of coating were conducted. The experimental results show that the coating has the better thermo-physical property by using plasma spray welding method with the powder ratio of 90% Ni60 and 10% Cr3C2, and by this way the micro-hardness of coating can achieve 1100 HV.
文摘采用Gleeble热模拟试验机对45Cr4Ni Mo V钢在变形温度1000～1150℃,应变速率0.002～5s-1,最大变形量为55%的条件下进行热模拟压缩试验。采用Poliak EI和Jonas J J等人对θ-σ（θ=dσ/dε为加工硬化率）曲线的描述,建立了45Cr4Ni Mo V钢在变形参数范围内的动态回复曲线（DRV）。通过对变形过程中的动态再结晶体积分数XD与应力参数之间的关系拟合,得到了45Cr4Ni Mo V钢在变形参数范围内的动态再结晶体积分数模型为：XD=1-exp-1.29ε-εcε0.5εε2.304εε。
基金The DFG(Deutsche Forschungsgemeinschaft)is gratefully acknowledged for the financial support(DFG No.PA 699/3-1 and FR 1603/1-2).
文摘Characteristic features of austenitic steel grades combine a good corrosion resistance with a low hardness, wear resistance and scratch resistance. An interesting possibility for improving the wear behaviour of these steels without loss of their corrosion resistance lies in enriching the near surface region with nitrogen. The process of a solution nitriding allows the rise of the solution of nitrogen in the solid phase. On this state nitrogen increases the corrosion resistance and the tribilogical load-bearing capacity. The aim of the study was, to investigate the improvement of the pitting corrosion behaviour by solution nitriding. A special topic was to observe the effect of nitrogen by different molybdenum content. So austenitic stainless steels (18% Cr, 12% Ni, Mo gradation between 0.06 to 3.6%) had been solution nitrided. The samples could be prepared with various surface content of nitrogen from 0.04 to 0.45% with a step-by-step grinding. The susceptibility against pitting corrosion of these samples had been tested by determination of the stable pitting potential in 0.5M and 1M NaCl at 25°C. For the investigated steel composition and the used corrosion system there is no influence of molybdenum on the effectiveness of nitrogen. The influence of nitrogen to all of the determined parameters can be described well by PRE = Cr + 3,3 * Mo + 25 *N. XPS analysis of the sample surfaces support the results of the pitting corrosion tests.Additionally surface investigations with an acid elektolyte (0,1M HC1 + 0,4M NaCl) were performed. In this case the passivation effective nitrogen content increases markedly with rising molybdenum concentration of the steel. Obviously an interaction of Mo and N is connected with a strongly acid electrolyte.
