退火温度对ECAP变形高氮奥氏体不锈钢力学性能的影响

Effect of annealing temperature on mechanical properties of ECAP high-nitrogen austenitic stainless steel

为研究等通道转角挤压(ECAP)+退火对高氮钢力学行为的影响,室温条件下对高氮钢进行1道次ECAP变形,之后分别在700、800、850、900℃下对不同N含量的试验钢进行退火处理,分析其力学性能变化规律。结果表明:高氮钢随着退火温度的升高,屈服强度和抗拉强度整体上呈下降的趋势,塑性随退火温度的升高而上升;不同状态高氮钢的抗拉强度与均匀延伸率之间都呈现了传统的强塑性之间的矛盾关系,随N含量的增加,呈现强度和均匀延伸率同步提高的趋势;高氮钢ECAP+低温退火后的拉伸断口呈现沿晶断裂形貌,随N含量的升高,沿晶断裂倾向更加明显。

In order to study the effect of equal channel angular pressing(ECAP)+annealing process on mechanical behavior of the highnitrogen steel,single pass ECAP deformation was performed on high-nitrogen steel at room temperature,and then the steel with different N contents was annealed at 700,800,850,900℃,respectively,to analyze the change rules of mechanical properties.The results show that the yield strength and tensile strength of the high-nitrogen steel decrease on the whole with the increase of annealing temperature,while the plasticity increases.The tensile strength and uniform elongation of the high-nitrogen steel at different annealing temperatures show the traditional inverse relationship,and the strength and uniform elongation increase synchronously with the increase of N content.The tensile fracture morphology of high nitrogen steel ECAP+annealed at low temperatures is intergranular,and intergranular fracture tendency is more obvious with the increase of N content.