Laser transformation hardening process and microstructure and properties of 780 MPa grade micro-alloy steel

被引：0
|
作者：
Sun Q. [1 ]
Di H.-S. [1 ]
Li J.-C. [1 ]
机构：
[1] The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang
来源：
Dongbei Daxue Xuebao/Journal of Northeastern University | 2016年 / 37卷 / 06期
关键词：
Laser transformation hardening; Martensite; Micro-hardness; Microstructure; Ultra-high strength steel; Wear resistance;
D O I：
10.3969/j.issn.1005-3026.2016.06.006
中图分类号：
学科分类号：
摘要：
A Nb-Ti-Mo micro-alloyed ultra-high strength hot-rolled low carbon steel was treated by laser induced phase transformation hardening process, using IPG 4 kW fiber laser. The effects of laser power and scanning speed on macroscopic morphology and mirco-hardness were investigated. The microstructure evolution in laser transformation zone was also discussed. The results showed that when the laser power increased or the scanning speed decreased, the width and depth of the laser transformation zone increased. Laser transformation zone can be characterized into three smaller zones in general: micro-melting zone (MZ), hardening zone (HZ) and transition zone (TZ). In this study, the microstructure in the MZ was ferrite, granular bainite and martensite, whereas the microstructure in the HZ was fully martensite, compared to the microstructure in the TZ which consisted of the relatively finer individual martensite and the structure mixed with ferrite and martensite. The average hardness of the HZ reached 320 HV, which was 30% higher than that of the matrix. The wear resistance of the steel was significantly improved by 30% after the laser treatment. © 2016, Science Press. All right reserved.
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页码：785 / 789
页数：4
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