高温冷却后奥氏体不锈钢力学性能试验研究

Experimental investigation on mechanical properties of austenitic stainless steel with elevated temperature cooling

基于奥氏体不锈钢S30408材料,研究不同温度工况下冷却后不锈钢材料的力学性能.考察空气中自然冷却和浸水冷却这2种方式对材料力学性能的影响,获取高温冷却后不锈钢材料的力学性能指标(弹性模量、名义屈服强度、抗拉极限强度和断后延伸率等)与相应的折减系数,并将试验结果和已有同类试验结果进行对比.结果表明:不同温度工况对不锈钢材料应力-应变曲线中应变值较大(>20%)的区段有着较为显著的影响;当温度工况<600℃时,不同温度工况和不同冷却方式对不锈钢材料的力学性能影响较小;当温度工况≥600℃时,不同温度工况和不同冷却方式对材料的弹性模量、名义屈服强度和断后延伸率存在着影响,且材料的抗拉极限强度随温度升高略为增长,但不同冷却方式对材料的抗拉极限强度几乎没有影响.

Based on S30408 austenitic stainless steel,the tensile tests on flat specimen were conducted to investigate behaviors of stainless steel after cooling down from various temperatures,and the influence from two cooling conditions(cooling in air and cooling in water)of material were inspected.The mechanical performance indexes,including elasticity modulus,offset yield strength,ultimate strength and elongation at break,were obtained,together with their reduction coefficient compared with indexes at room temperature.Comparison was made between the experiment results and the results of similar tests.The results indicate that,various heating temperatures have significant effect on the part with higher strain value(more than 20%)in strain-stress curve.When heating temperatures are under 600 ℃,the mechanical properties of stainless steel change little with the increase of temperatures or with the switch of cooling conditions.However,when heating temperatures are greater than or equal to 600℃,the variation of both temperatures and cooling methods obviously affects elasticity modulus,offset yield strength and elongation at break.Ultimate strength increases slightly with the growing temperatures above 600℃,but almost remains unchanged between different cooling conditions.