回火温度对690MPa级工程机械用钢组织与性能的影响  

Effect of tempering temperature on microstructure and mechanical properties of 690 MPa grade engineering machinery steel

作　　者：蒋长虹[1,2] 惠亚军[1] 赵爱民[1] 赵征志[1] 黄耀[1] 李蕾[1] 李文远[1] 武会宾[1] 

机构地区：[1]北京科技大学冶金工程研究院,北京100083 [2]太原钢铁集团有限公司,山西太原030003

出　　处：《材料热处理学报》2013年第6期103-109,共7页Transactions of Materials and Heat Treatment

摘　　要：设计了一种低碳Fe-Mn-Nb-Cu-B系屈服强度690 MPa级工程机械结构用钢,利用扫描电镜(SEM)和透射电镜(TEM)等仪器研究了不同回火温度对实验钢的组织和性能的影响。结果表明:回火温度对屈服强度和抗拉强度均有较大影响,都呈现出先降低再升高再降低的规律。600℃回火时的综合力学性能较好,屈服强度比未回火时增加了145 MPa;并且屈强比和硬度随回火温度的变化趋势同抗拉强度和屈服强度的变化规律是相同的。分析认为:回火前后力学性能的变化的主要原因是与回火后有更多弥散的尺寸在20 nm以下的新的细小(Nb,Ti)(N,C)粒子析出以及发生位错的回复和M-A岛的分解有关。A low-carbon Fe-Mn-Mo-Nb-Cu-B 690 MPa grade structural steel for construction machinery was designed and the effects of tempering temperature on microstructure and mechanical properties of the steel were investigated by means of scanning electron microscopy （ SEM ） and transmission electron microscopy （ TEM ）. The results show that tempering temperature has considerable influence on both the yield strength and the tensile strength. The yield strength and the tensile strength decrease first, and increases to the maximum value of 840 MPa, and then decline with the increasing tempering temperature. In comparison with the as-received steel, the yield strength of the steel tempered at 600 ℃ increases by 145 MPa. The changing trend of the yield/tensile ratio and hardness with the tempering temperature is the same with the variation of tensile and yield strength. The change of mechanical properties after tempering is relative to the dispersive precipitates with the size of less than 20 nm, the recovery of dislocations and the decomposition of large M-A islands.

关 键 词：低碳Fe-Mn-Nb-Cu-B钢回火温度 显微组织 力学性能 

分 类 号：TG156.5[金属学及工艺—热处理] TG142.4[金属学及工艺—金属学]