65Cr5Mo3W2VSiTi钢中下贝氏体/马氏体复相组织韧性的研究

对65Cr5Mo3W2VSiTi(LM2)钢常规淬火组织和部分等温淬火组织的冲击韧性和断裂韧性进行了测试,对比研究了显微组织(主要指 B_l和 A_R 数量)和回火温度对LM2钢下贝氏体/马氏体(B_l/M)复相组织韧性的影响。用连续扫描拉伸技术分析了裂纹的萌生、扩展至断裂全过程与显微组织的关系。通过 U 型缺口试样的示波单冲试验,分析了显微组织对裂纹萌生功和扩展功的影响及其对缺口冲击韧性的贡献。试验结果表明,含有40%～60%B_1的复相组织随后200℃回火,对钢有显著地韧化效果。文中还较详细地探讨了高碳高合金钢中复相组织的断裂机制。

FATIGUE BEHAVIOUR OF M/B DUPLEX STRUCTURE IN A HIGH CARBON Cr-Mo-W STEEL

Determination was carried out of fatigue crack propagation rate of steel 65Cr5Mo3W2VSiTi (LM2)with various bainite contents and M/B duplex structure tempered at various tempera- tures.The threshold value of fatigue for each processing was estimated by experimental data. The mechanism for fatigue crack propagation of M/B duplex structure in steel LM2 seems to be non-continuous.The calculated fatigue crack micro-propagation rates are found to agree with the experimental data.