摘要
研究了不同微合金化的高Co-Ni超高强度钢A-100在标准热处理以及高温处理(模拟锻造死区状态)的拉伸力学性能及断口形貌.结果表明,在标准热处理条件下材料的综合力学性能优异,高温+标准热处理之后强度变化不大,但断后伸长率和断面收缩率显著下降.加入稀土元素Ce,高温+标准热处理后的塑性损失情况大大改善.高温处理使微观组织从标准热处理下的细小均匀板条马氏体变为粗大的板条马氏体,使拉伸断口由韧性断裂的韧窝状变为脆性沿晶断裂的“冰糖状”.沿晶断裂刻面为大量细小的韧窝,韧窝底部存在大量碳化物颗粒.加入Ce元素后断口出现了部分穿晶断裂,脆性开裂状态有所改善,与力学性能的提高相对应.在进行锻造工艺设计和生产过程中应尽量避免形成不变形的“锻造死区”.
Tensile properties and fracture topography of micro-alloyed high Co-Ni ultra-high strength steel A-100,under standard heat-treatment or high-temperature+standard heat-treatment,simulating the“dead zone”of forging,are studied.The results indicate the excellent comprehensive mechanical properties of the material under the standard heat treatment condition.The elongation and reduction of area decrease significantly after high-temperature+standard heat-treatment,with relatively stable strength.This plastic loss is greatly reduced with the addition of rare earth element Ce.The microstructure of fine and uniform lath martensite under standard heat treatment is transformed to coarse lath martensite,and the tensile fracture of ductile dimple shape to brittle intergranular fracture by high-temperature treatment.The facet of intergranular fracture consists of a large number of small dimples which contain a large number of carbide particles at the bottom.After addition of Ce,the brittle intergranular fracture is slightly replaced by transgranular fracture,corresponding to the improvement of tensile properties.The formation of“dead zone”without deformation should be avoided as far as possible in the process of design and producing of forging.
作者
李杰
向锋
LI Jie;XIANG Feng(College of Mechanical Engineering,Hunan Institute of Engineering,Xiangtan 411104,China)
出处
《湖南工程学院学报（自然科学版）》
2022年第3期26-31,共6页
Journal of Hunan Institute of Engineering(Natural Science Edition)
基金
湖南省教育厅科研资助项目(18C0713).
关键词
超高强度钢
A-100钢
稀土元素
锻造死区
沿晶断裂
ultra-high strength steel
A-100 steel
rare earth
forging dead zone
intergranular fracture
