含硼、钴9%Cr耐热钢的热变形行为

Hot deformation behavior of 9%Cr steel contained B and Co elements

热机械模拟试验是研究新型含硼、钴9%Cr耐热钢材料的有效方法,试验在温度T为900～1050℃、应变速率ε·为0.001～10s-1条件下进行,确定材料的热变形参数。利用相关试验数据建立基于峰值应力的新型含硼、钴9%Cr耐热钢本构方程,并以动态材料模型和Murthy失稳准则为理论基础,绘制材料的热加工图。试验结果表明:含硼、钴9%Cr耐热钢在高温下有较好的塑性,变形温度和变形速率对其高温塑性影响不大,但对动态再结晶的影响比较明显。将试验后的试样进行抛光腐蚀,并利用光学显微镜对含硼、钴9%Cr耐热钢在不同变形条件下的组织演变进行观察,进而研究动态再结晶生成及变化规律。

Thermomechanical simulation test is an effective method to study the new 9Cr heat-resistant steel.The experiment is carried out under the conditions of temperature 900~1050℃ and strain rate of 0.001~10^s-1 to determine the thermal deformation parameters.The constitutive equation of the new 9Cr heat-resistant steel based on the peak stress was established and the hot processing map of materials was drawn from the dynamic material model and Murthy instability criteria.The results show that the temperature and strain rate of deformation have little influence on plasticity of new 9Cr steel,but play a decisive influence on the dynamic recrystallization.The microstructure evolution of new 9Cr steel under different conditions was observed by optical microscope,and then the dynamic recrystallization and the variation were studied.