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以珠光体钢为研究对象,在不同盐浴温度下等温获得不同特征的珠光体组织。进行了力学性能测试与准静态断裂韧性(J0.2BL)测试,在扫描电子显微镜(SEM)下观察了微观组织与裂纹扩展路径。研究结果表明,珠光体片层间距与铁素体量对断裂韧性具有显著影响,裂纹扩展阻力由珠光体片层间距以及先共析铁素体含量共同决定,根据不同组织对裂纹扩展阻力的贡献值珠光体钢裂纹扩展总阻力可用表达式δ(SUM)=k’δ(P)+kδ(F)来进行描述,随着等温温度的增加,珠光体片层间距与先共析铁素体量增加,珠光体钢裂纹扩展总阻力呈先上升后下降的趋势,与J0.2BL实验结果具有一致的趋势。
Taking pearlite steel as the research object, different characteristics of pearlite were obtained at different temperature of salt bath. Mechanical properties and quasi-static fracture toughness (J0.2BL) tests were carried out. The microstructure and crack growth path were observed under a scanning electron microscope (SEM). The results show that the interlamellar spacing of pearlite and the amount of ferrite have a significant effect on the fracture toughness. The crack propagation resistance is determined by the spacing of pearlite sheets and the content of pro-eutectoid ferrite. According to the contributions of different tissues to the crack propagation resistance The total crack propagation resistance value of pearlite steel can be described by the expression δ (SUM) = k’δ (P) + kδ (F). As the isothermal temperature increases, the pearlite layer spacing is proportional to the pro-eutectoid ferrite The total resistance of pearlite steel increases firstly and then decreases, which is consistent with the experimental result of J0.2BL.