摘要
对球化退火后的5Cr8Mo2Si V刃具钢进行淬火和回火工艺的探究,用SEM和EDS对淬、回火后的显微形貌进行分析,用碳化物电解萃取和XRD分析等研究了5Cr8Mo2Si V刃具钢淬、回火过程中碳化物的析出行为,并用Jmat-Pro模拟回火过程中碳化物析出相的变化。结果表明:5Cr8Mo2Si V钢退火试样在1100℃淬火+520℃回火时有明显的二次硬化现象,球化退火组织中存在VC、Cr_(23)C_6、Cr_7C_3、Fe_3C、Si C和Mo_6C类碳化物。Mo_6C、Si C、Fe_3C、Cr_7C_3和Cr_(23)C_6型碳化物随着淬火温度升高依次溶入马氏体基体,最终只有VC分布在基体上。Mo_2C、VC、Cr_7C_3和Cr_(23)C_6型碳化物在回火过程中从马氏体中析出,且Mo_2C和VC型碳化物在520℃回火析出量出现峰值。结合Jmat-Pro模拟结果发现,5Cr Mo2Si V钢的二次硬化现象是残留奥氏体二次淬火和Mo_2C粒子的第二相强化共同导致,且Mo_2C粒子第二相强化效应符合位错切过机制。
Quenching and tempering heat treatment processes were designed for spheroidized 5Cr8Mo2 Si V steel to obtain the highest hardness. Microstructure of 5Cr8Mo2 Si V steel was observed by SEM and EDS. Carbide precipitation behavior during quenching and tempering process was analyzed by XRD and carbides-extraction method. And the change of carbide-precipitate phases during quenching and tempering process was simulated by Jmat-Pro software. The results show that the secondary hardening peak of spheroidized 5Cr8Mo2 Si V steel appear at 1100 ℃ quenching ＋ 520 ℃ tempering. VC,Cr_（23）C_6,Cr_7C_3,Fe_3 C,Si C and Mo_6 C exist in spheroidized structure. With the quenching temperature increasing,Mo_2 C,Si C,Fe_3 C,Cr_7C_3 and Cr_（23）C_6 successively dissolve into the matrix. Mo_2 C,VC,Cr_7C_3 and Cr_（23）C_6 precipitate from the matrix during tempering process. And Mo_2 C and VC particles precipitate massively at about 520 ℃. Combining with the simulation results of Jmat-Pro,it is found that the secondary hardening phenomenon of 5Cr8Mo2 Si V steel is the combination of the transformation of retained austenite and the Mo_2 C particles precipitation. The second-phase strengthening of Mo_2 C particle accords with dislocations-cut mechanism.
出处
《金属热处理》
CAS
CSCD
北大核心
2017年第3期98-103,共6页
Heat Treatment of Metals
作者简介
黄顶俊（1992-），男，硕士研究生，主要研究方向为5Cr8M02SiV合金钢的热处理优化及耐磨性研究，E—mail：huangdingjun@shu．edu．cn。
通讯作者：杨弋涛，教授，博士，E-mail：yyt@staff．shu．edu．cn
