【摘要】 研究淬火后回火温度对ZG40Cr组织和力学性能的影响。结果表明,ZG40Cr淬火后随回火温度的升高,力学性能呈下降趋势,450℃回火冲击值最低,出现回火脆性,超过450℃回火冲击值随回火温度的提高上升幅度较大。ZG40Cr淬火、200℃回火组织为回火马氏体,具有较高的强度和较低的冲击值,超过300℃回火组织中析出碳化物。随回火温度的提高,析出的碳化物有积聚粒状化趋势,650℃回火组织为索氏体组织,具有较高的强韧性。淬火后200℃回火的冲击断口形貌为准解理断裂,伴随一定塑性变形的撕裂棱;450℃回火的冲击断口形貌主要为沿晶断裂特征;650℃回火的冲击断口形貌为韧窝断裂,存在大量塑性变形。更多还原

【Abstract】 The effects of tempering temperature on the microstructure and properties of ZG40Cr steels quenched at 860℃ were studied.The results show that the mechanical properties decrease with increase of the tempering temperature lower than 450 ℃.The tempering embrittlement occurs at 450 ℃ where the impact toughness gets its minimum value and the impact property substantially increases when the tempering temperature is higher than 450 ℃.ZG40Cr Steels tempered at 200 ℃ has high strength and low impact toughness with tempered martensite.When the tempering temperature exceeding to 300 ℃,the carbides precipitated in the tempered structure and the granular carbides gradually forms with the increase of the tempering temperature.ZG40Cr steels tempered at 650 ℃ has the microstructure of tempered sorbite with high strength and toughness.The impact fracture morphology has the characteristic of quasi-cleavage fracture with tear ridges,intergranular fracture and dimple fracture when ZG40Cr steels are tempered at 200 ℃,300 ℃ and 650 ℃,respectively.更多还原