高强度马氏体时效不锈钢的晶粒细化及其力学性能的研究

Study of Grain Refining Process and Mechanical Properties of a High Strength Maraging Stainless Steel

研究了一种高强度马氏体时效不锈钢逆转变奥氏体再结晶规律、细化晶粒工艺及细晶组织对力学性能的影响。研究表明,通过循环相变α′γ可得到7μm的等轴晶粒,新生晶粒内的板条马氏体块又重新被分割而成为若干个亚晶粒,同时部分单一的马氏体板条束又被夹角略大于60°方向上的若干个小马氏体板条束所分割,从而进一步细化了马氏体组织;与传统热处理工艺1 050℃×1 h相比,在同样时效处理规程下进行时效处理,钢的屈服强度提高了130 MPa,A、Z分别提高了7.5%、11%,循环相变细化晶粒是同时提高该钢的强度和韧塑性的有效手段。

Reverse austenization, grain refining and effect of grain refined structure on mechanical properties of a high strength maraging stainless steel were studied. The results show that the steel with 7 μm grains was acquired by thermo-cycle refining treatment, many martensite lath blocks were partitioned into some sub-grains, and a few single lathes were partitioned by some martensite lath packets in new refined grains; compared with the steel treated by 1050 ℃×1 h, the yield strength of thermo-cycle refined steel was increased by 130 MPa,A and Z were increased by 7.5% and 11%,so that thermo-cycle refining treatment is a new efficient method to improve both strength and toughness of maraging stainless steel.