摘要
40CrNi2Si2MoV马氏体钢中大尺寸碳化物存在会影响其力学性能,通过成分设计优化和合理的热处理工艺可以有效提高材料的强韧性。研究了M_(6)C碳化物在不同淬火温度(860~1150℃)下对超高强度钢力学性能及显微组织的影响,并通过SEM、TEM等表征方法对M_(6)C颗粒尺寸、数量及成分的演变进行了研究。结果表明,大尺寸M_(6)C颗粒使超高强度钢韧性降低,880℃淬火试样中的M_(6)C颗粒尺寸较大(~400 nm),容易在大尺寸M_(6)C周围造成应力集中,减弱了基体与M_(6)C碳化物的结合力,易在M_(6)C碳化物周围萌生裂纹,致使材料发生断裂。随着淬火温度升高,试验钢中M_(6)C颗粒尺寸减小、数量降低,且提升了M_(6)C颗粒中Si的浓度,M(Fe、Mo、Ni、Co)6C中原子被Si取代,提升了M_(6)C碳化物的稳定性;1050℃淬火温度试验钢中M_(6)C颗粒尺寸为25 nm,同时抑制原始奥氏体晶粒(8.5μm)长大,试验钢抗拉强度为2227 MPa,伸长率为7.0%,实现良好的强韧性匹配。
The mechanical properties of 40CrNi2Si2MoV martensitic steel are affected by the large size carbides,the strength and toughness of martensitic steel can be effectively improved by optimizing the composition design and reasonable heat treatment process.The effects of M_(6)C carbide on mechanical properties and microstructure of ultrahigh strength steel were studied at different quenching temperatures(860℃-1150℃),and the evolution of M_(6)C particle size,quantity and composition was studied by means of SEM and TEM.The results show that large M_(6)C particles reduce the toughness of ultrahigh strength steel,and the M_(6)C particles in the 880℃quenching sample are large(~400 nm),which is easy to cause stress concentration around the large M_(6)C carbide,weaken the binding force between the matrix and M_(6)C carbide,and easy to crack around M_(6)C carbide,resulting in material fracture.With the increase of quenching temperature,the size and quantity of M_(6)C particles in the test steel decrease,and the concentration of Si in M_(6)C particles is increased,and the atoms in M(Fe,Mo,Ni,Co)6C are replaced by Si,which improves the stability of M_(6)C carbide.The size of M_(6)C particle in the 1050℃quenching temperature test steel is 25 nm,and the growth of the original austenite grain(8.5μm)is inhibited.The strength of the test steel is 2227 MPa and the elongation is 7.0%,achieving a good strength and toughness matching.
作者
唐远寿
张十庆
李方
何钦生
赵振
王宏
邹兴政
王建桥
黄雅丽
Tang Yuanshou;Zhang Shiqing;Li Fang;He Qinsheng;Zhao Zhen;Wang Hong;Zou Xingzheng;Wang Jianqiao;Huang Yali(Chongqing Materials Research Institute Co.,Ltd.,Chongqing 400700,China)
出处
《特殊钢》
2024年第5期108-112,共5页
Special Steel
基金
重庆英才-创新领军人才(CQYC20210301302)。
