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利用Olympus光学显微镜、扫描电镜(SEM)、落锤冲击试验机和电子万能试验机,分析了某低合金铸钢基体堆焊制造锻模失效前后低合金铸钢基体的组织和性能。锻模工作过程中铸钢基体经受热循环和应力循环,铸钢基体出现软化。金相显微组织及冲击断口扫描结果表明,失效前后低合金铸钢基体显微组织均为回火索氏体,表面未见到显微裂纹;失效后冲击断口出现了明显断裂特征。力学性能测试结果表明,失效后铸钢基体抗拉强度、屈服强度、伸长率及断面收缩率均有所降低,抗拉强度和屈服强度下降比例分别为8.62%和10.63%。
The microstructure and properties of the low alloy cast steel matrix before and after the failure of the forging die of a low alloy cast steel substrate were analyzed by using Olympus optical microscope, scanning electron microscope (SEM), drop weight impact tester and electronic universal testing machine. During the forging process, the cast steel matrix undergoes thermal cycling and stress cycling, and the cast steel matrix softens. Metallographic microstructure and impact fracture scanning results show that before and after failure, the microstructure of the low alloy steel substrate is tempered sorbite, no micro-cracks are observed on the surface, and obvious fracture characteristics are observed on the impact fracture after failure. The test results of mechanical properties show that the tensile strength, yield strength, elongation and reduction of area of the cast steel matrix decrease after failure, and the decrease of tensile strength and yield strength are 8.62% and 10.63% respectively.