马氏体板条细化机制及其对马氏体钢力学性能的影响

Refining Mechanism of Martensitic Lath and Influence on Mechanical Properties of Martensitic Steel

以00Cr11Ni4Mo低碳马氏体不锈钢为研究对象,研究一次正火、循环正火、正火+回火处理对其组织和性能的影响,分析马氏体板条细化对低碳马氏体钢力学性能的影响,并阐明马氏体板条的细化机制。结果表明,采用一次正火温度为900℃的热处理工艺得到的屈服强度、极限抗拉强度、延伸率分别为961 MPa、1093 MPa、20.7%,综合力学性能最佳;随着正火温度的升高,马氏体板条粗化,其极限抗拉强度和屈服强度下降,塑性呈先上升后下降的趋势。循环正火热处理并没有达到提高材料强度的效果,对塑性的改善也有限。正火+回火热处理工艺细化了马氏体板条,但并未提高材料的强度。通过马氏体板条细化来提高材料强度具有一定的局限性,需要综合考虑更多影响材料强塑性的因素。

00Cr11Ni4Mo low-carbon martensitic stainless steel was used as the research object.Effects of different heat treatment processes on the microstructure and mechanical properties of 00Cr11Ni4Mo low-carbon martensitic steel was investigated by means of single normalizing,cyclic normalizing,normalizing and tempering,respectively.The effect of martensitic lath refining on mechanical properties of low-carbon martensitic steel was analyzed.And the refining mechanism of martensitic lath was clarified.The results showed the yield strength,ultimate tensile strength and elongation were 961 MPa,1093 MPa and 20.7%,respectively,and the comprehensive mechanical properties were the best when the primary normalizing temperature was 900℃.With the increase of normalizing temperature,martensitic lath coarsing,the ultimate tensile strength and yield strength decreased,but the plasticity of the material first increased and then decreased.The cyclic normalizing heat treatment had not achieved the effect of improving the strength of the material,and the improvement of plasticity was limited.The normalizing and tempering heat treatment process refined martensitic lath,but did not improve the strength of the material.There were certain conditions to improve the strength of materials by refining martensitic lath,and more factors affecting the strength and plasticity of the material should be considered comprehensively.