固溶处理对022Cr22Ni5Mo3N双相不锈钢组织及低温冲击性能的影响

Effect of solution treatment on microstructure and low temperature impact properties of 022Cr22Ni5Mo3N duplex stainless steel

对锻态022Cr22Ni5Mo3N双相不锈钢进行固溶处理,研究了固溶温度(1000~1100℃)和时间(1h和2h)对其组织及-46℃低温冲击性能的影响。结果表明,随着固溶温度的升高,022Cr22Ni5Mo3N双相不锈钢中奥氏体含量呈下降趋势,奥氏体的相界趋于平滑,铁素体内的针状、岛状奥氏体数量逐渐减少。低温冲击性能随固溶温度的升高呈先上升后下降趋势;经1050℃固溶处理的022Cr22Ni5Mo3N双相不锈钢具有较高的低温冲击吸收能量,约为260J。固溶处理可以改变奥氏体的相形态,调整相含量,固溶温度小于1050℃时的锯齿状相界和固溶温度大于1050℃时较低的奥氏体相含量均促使双相钢在低温时偏向脆性断裂,是降低低温韧性的主要原因。

Solution treatment for as-forged 022Cr22Ni5Mo3N duplex stainless steel was carried out,and the effects of solution temperature(1000-1100℃)and time(1 h and 2 h)on the microstructure and-46℃low temperature impact properties were studied.The results show that with the increase of solution temperature,the austenite content of the 022Cr22Ni5Mo3N stainless steel decreases,the phase boundary of austenite tends to be smooth and the number of needle-type and island austenite in ferrite decreases gradually.The low temperature impact properties increase first and then decrease with the increase of solution temperature.When the solution temperature is 1050℃,the low temperature impact absorbed energy of the 022Cr22Ni5Mo3N stainless steel is higher,which is about 260 J.The solution treatment can change the austenite phase morphology and adjust the phase content.Serrated phase boundaries(below 1050℃)and lower austenite phase content(above 1050℃)promote the brittle fracture of dual-phase steels at low temperatures,which is the main reason for the reduction of low-temperature toughness.