Optimization of hot working parameters for thermo-mechanical processing of modified 9Cr―1Mo (P91) steel employing dynamic materials model
Optimization of hot working parameters for thermo-mechanical processing of modified 9Cr―1Mo (P91) steel employing dynamic materials model
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DOI：
10.1016/j.msea.2011.03.025
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发表时间：
2011-06
期刊：
影响因子：
6.4
通讯作者：
Dipti Samantaray;S. Mandal;A. K. Bhaduri
中科院分区：
文献类型：
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作者：
Dipti Samantaray;S. Mandal;A. K. Bhaduri
在较宽的温度(1123K-1373K)和应变速率(0.001-10S−1)范围内，研究了改性9Cr-1Mo钢的本征加工性能。利用等温热压缩试验获得的实验数据，采用动态材料模型(DMM)方法绘制了0.5真应变下的加工图。开发了激活能图，以证实加工图所获得的结果，并最终确定了最佳工艺参数。已经进行了微观结构研究，以验证加工图的结构域。当应变速率高于1S−1时，该材料在1150-1373K温度范围内出现局域变形带；在较高温度(1373K)和较低应变速率(0.001-0.01s−1)下，该材料表现出异常伸长的马氏体条。热变形的最佳温度范围为1250K~1350K，应变速率范围为0.015~0.3s−1，峰值效率为38%。在此区域内，表观活化能为400kJ/mol。在该区域变形的样品的显微组织为无缺陷的等轴晶。
Intrinsic workability of modified 9Cr–1Mo steel has been studied in a wide range of temperatures (1123–1373K) and strain rates (0.001–10s−1). Using the experimental data obtained from isothermal hot compression tests, processing map at 0.5 true strain has been developed employing dynamic material model (DMM) approach. The activation energy map has been developed to substantiate the results obtained from processing map and to finalize the optimum processing parameters. Microstructural studies have been carried out to validate the domains of the processing map. The material shows localized deformation bands in the temperature range of 1150–1373K at strain rates above 1s−1and exhibits abnormally elongated martensite laths at higher temperature (1373K) and lower strain rates (0.001–0.01s−1). The optimum domain for the hot deformation is found to be in the temperature ranges of 1250–1350K and strain rate ranges 0.015–0.3s−1with a peak efficiency of 38%. In this domain, apparent activation energy is found to be 400kJ/mol. The microstructure of the specimens deformed in this region exhibits defect free equiaxed grains.