固溶温度对2507双相不锈钢力学性能及耐蚀性的影响

Effect of solution temperature on mechanical properties and corrosion resistance of super duplex stainless steel 2507

利用光学显微镜、扫描电镜、XRD、拉伸试验机和电化学综合测试仪等研究了不同固溶温度对2507超级双相不锈钢组织、力学性能和耐蚀性的影响。采用Thermo-Calc热力学软件计算了2507双相不锈钢的热力学平衡相图,并与测试结果进行了对比。研究结果表明,经1050℃及以上温度固溶后,σ相溶解;随着固溶温度的升高,铁素体相含量增加,奥氏体相含量降低,α/γ相体积分数比增加;1050~1100℃固溶30 min并水冷时,双相不锈钢具有较好的综合力学性能,屈服强度、抗拉强度和伸长率分别大于600 MPa、840 MPa和35%。1050℃固溶30 min时,双相钢可获得较好的耐蚀性能。

Effect of solution temperature on microstructure, mechanical properties and corrosion resistance of 2507 super duplex stainless steel was investigated by using optical microscope, scanning electron microscopy, XRD, tensile test and electrochemical analysis. The thermodynamic equilibrium phase diagram of the 2507 duplex stainless steel was calculated by Thermo-Calc thermodynamic software and compared with the test results. The results show that σ phase can be eliminated by solution treatment at temperatures higher than 1050 ℃. With the increase of solution temperature, the content of ferrite phase increases, the content of austenite phase decreases, and the volume fraction ratio of α/γ increases. The duplex stainless steel has better comprehensive mechanical properties after solution treatment at 1050-1100 ℃ for 30 min and water cooling, of which the yield strength, tensile strength and elongation are more than 600 MPa, 840 MPa and 35%, respectively. The duplex stainless steel can obtain better corrosion resistance after solution treatment at 1050 ℃ for 30 min.