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对热轧25MnV钢石油套管进行了不同工艺的淬火热处理试验,通过组织观察和力学性能测试等手段,对比研究了直接淬水冷却至室温和水-空-水交替淬火两种工艺对合金显微组织与力学性能的影响。结果表明:水-空-水交替淬火可有效减缓石油套管的淬火内应力,所得马氏体+下贝氏体的复相组织可降低淬火裂纹产生和扩展的趋势,提高了石油套管的使用安全性。经590℃×65 min回火后,套管的抗拉强度达到932 MPa,屈服强度为870 MPa,横向冲击功高达55 J,综合力学性能远远超过当前的调质态套管,分析认为这归功于复相组织中微细孪晶马氏体的减少以及部分下贝氏体和少量残留奥氏体等二次析出相的综合作用。
The hot-rolled 25MnV steel casing was quenched and heat-treated by different processes. The microstructure and mechanical properties of 25MnV hot-rolled steel casing were compared. The effects of direct quenching cooling to room temperature and alternating water-air- Effect of Micro-organization and Mechanical Properties. The results show that alternating water-air-water quenching can effectively reduce the quenching internal stress of the oil casing, and the resulting composite martensite + lower bainite structure can reduce the tendency of quenching crack to develop and expand, Use security After 590 ℃ × 65min tempering, the tensile strength of the casing reaches 932 MPa, the yield strength is 870 MPa and the transverse impact energy is 55 J. The comprehensive mechanical properties far exceed that of the current quenched and tempered casing. Due to the reduction of fine twinned martensite in the complex phase and the combined effects of secondary bainite phases such as lower bainite and a small amount of retained austenite.