40CrNiMoA大型锻件组织与性能的研究

摘要

针对40CrNiMoA材料调质处理后强度变化的反常现象，分析研究了该材质调质后的组织与性能关系。研究表明，40CrNiMoA锻件尺寸较大，当淬火冷却的终冷温度过高时，锻件调质后由表面到芯部金相组织依次为回火索氏体→回火索氏体＋贝氏体→回火贝氏体，从而引起强度由表面到芯部逐渐增大的反常现象。%In view of abnormal strength of a 40CrNiMoA forging after quenching and tempering, the paper studied the relationship between its microstructure and properties. The study results showed: due to the large volume of the 40CrNiMoA forging, when the final cooling temperature after quenching was overhigh, the microstructure of the forging after quenching and tempering was tempered sorbite, tempered sorbite and bainite, bainite from surface to core, which brought about the anomaly that the strength increased from surface to core. The malleability of 40CrNiMoA torsion bar was worst when the microstructure was tempered sorbite and bain- ite, and better when the microstructure was only tempered sorbite or only bainite.