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探讨了30CrMnSiA钢亚温淬火强韧性变化规律和机制。用金相分析和定量金相分析研究了亚温淬火后的各种组织形态,用硬度、冲击、拉伸、断裂韧性试验方法测定了相应的强韧性变化规律,用扫描电镜断口形貌分析和断口剖面金相分析研究了裂纹扩展特点。结果表明,亚温淬火后若经高温回火,针状复合组织中的裂纹系通过相界面和剪断铁素体而交替扩展;小颗粒状组织中的裂纹仅沿相界面而扩展;大颗粒状组织中的裂纹则以解理断裂方式通过铁素体。亚温淬火后若经低温回火,无论对于何种形态的复合组织,裂纹均系通过铁素体本身解理断裂而形成,并以解理方式通过铁素体而扩展。
The change rule and mechanism of the quenching toughness of 30CrMnSiA steel were discussed. Metallographic analysis and quantitative metallographic analysis of various microstructures after sub-temperature quenching, with the hardness, impact, tensile and fracture toughness test method to determine the corresponding changes in toughness, with the scanning electron microscopy fracture morphology analysis and Fracture section metallographic analysis of the crack propagation characteristics. The results show that if the tempered austenite is tempered at high temperature, the cracks in the acicular composite microstructure extend alternately through the interface and cut the ferrite; the cracks in the small granular structure extend only along the phase interface; Tissues in the crack through the cleavage fracture way ferrite. If sub-temperature quenching after tempering at low temperature, no matter what the shape of the composite structure, the cracks are formed by the cleavage of the ferrite itself cleavage and cleavage by way of ferrite and expansion.