E级钢调质处理后的组织与性能

通过优化E级钢的调质热处理工艺,找到该钢调质后低温冲击性能提高的内在原因。并用光学显微镜对钢的显微组织进行分析,用拉伸试验机对经不同热处理后E级钢试件的拉伸性能和-40 ℃冲击性能进行检测。结果表明,在910 ℃淬火回火后,得到均匀的索氏体组织,冲击性能最佳。通过对冲击断口的观察和钢中碳化物析出行为的研究,指出E级钢调质处理后的韧性与碳化物的形貌与分布有关,低于550 ℃回火时,钢中的碳化物主要在板条边界和晶界析出,低温冲击性能低;高于550 ℃回火时,碳化物主要在晶内析出,呈粗粒状,且铁素体呈等轴状,冲击性能较高。

Microstructure and properties of grade E steel after quenching and tempering treatment

Through the optimization of quenching and tempering heat treatment process of grade E steel, the internal reason for the increase of low temperature impact properties was obtained. The microstructure of the steel was studied by optical microscope, and the tensile properties and -40 ℃ impact properties of grade E steel after different heat treatments were studied by tensile testing machine. The results show that uniform sorbite structure is obtained after quenching at 910 ℃ and tempering, and the impact properties is the best. Through the observation of the impact fracture and the study of the precipitation behavior of carbides in steel, the results show that the toughness of the grade E steel quenched and tempered is related to the morphology and distribution of carbides. When tempering temperature is below 550 ℃, carbides mainly precipitate at lath boundary and grain boundary, the impact properties of low temperature is low. When tempering temperature is above 550 ℃, carbides mainly precipitate in the grain and are coarse grained and the ferrite is equiaxed, the impact properties is high.