超级双相不锈钢00Cr32Ni7Mo3.5N的热塑性及高温组织演变

Thermo-plasticity and high-temperature microstructure evolution of hyper duplex stainless steel 00Cr32Ni7Mo3.5N

为研究超级双相不锈钢00Cr32Ni7Mo3.5N(SAF3207)的高温热塑性,对3207钢进行热拉伸实验并分析断口形貌。结果表明,提高加热温度至1300℃、应变速率到0.1s-1时,能使断面收缩率达82.7%,随着温度从1000℃上升至1300℃,热塑性依次增大,断裂方式从脆性断裂转变至韧性断裂。与00Cr25Ni7Mo4N(SAF2507)双相不锈钢相比,3207钢的热塑性低于2507钢,3207钢的开轧温度为1300℃,其终轧温度必须高于1150℃。而2507钢的开轧温度为1250℃,终轧温度高于1000℃。使用Thermo-Calc软件计算双相钢的平衡相图,对双相钢进行了不同温度热处理以观察其高温组织的演变规律,并结合铁素体测量结果分析了钢的热塑性与温度的关系。

To study the high temperature thermo plasticity of hyper duplex stainless steel （HDSS） 00Cr32Ni7Mo3.5N （SAF3207）, hot tensile tests were conducted and the fracture morphology was analyzed. The results show that the percentage reduction of area can reach 82.7% with the temperature and the strain rate increasing to 1300 ℃ and 0. 1 s-1 respectively. With the temperature rising from 1000 ℃ to 1300 ℃, thermo-plasticity increases and the fracture mode changes from brittle fracture to ductile fracture. The thermo-plasticity of 3207 HDSS is lower compared with 00Cr25Ni7Mo4N （SAF2507） HDSS. The blooming temperature of 3207 HDSS is 1300 ℃ and its final rolling tempera- ture must be higher than 1150 ℃. Whereas the blooming temperature of 2507 HDSS is 1250 ℃ and its finishing tem- perature is higher than 1000 ℃. The equilibrium phase diagram of 3207 HDSS is calculated with Thermo-Calc soft- ware. The steel was heat treated at different temperatures to observe its microstructure evolution in high temperature and the content of ferrite was measured to analyze the relationship between thermo-plasticity and temperature.