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[1]杨立军,孙明升,王金凤,等.DP980超高强钢激光焊接接头组织及性能研究[J].天津大学学报(自然科学版),2017,(03):290-294.[doi:10.11784/tdxbz201511002]
 Yang Lijun,Sun Mingsheng,Wang Jinfeng,et al.Microstructure and Properties of Laser Welding Ultra-High Strength Steel DP980 Joints[J].Journal of Tianjin University,2017,(03):290-294.[doi:10.11784/tdxbz201511002]
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DP980超高强钢激光焊接接头组织及性能研究()
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《天津大学学报(自然科学版)》[ISSN:0493-2137/CN:12-1127/N]

卷:
期数:
2017年03
页码:
290-294
栏目:
材料科学与工程
出版日期:
2017-03-23

文章信息/Info

Title:
Microstructure and Properties of Laser Welding Ultra-High Strength Steel DP980 Joints
作者:
杨立军1 孙明升1 王金凤12 刘桐1
1. 天津大学材料科学与工程学院,天津 300072;2. 湖北汽车工业学院材料科学与工程学院,十堰 442002
Author(s):
Yang Lijun1 Sun Mingsheng1 Wang Jinfeng12 Liu Tong1
1. School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
2. School of Materials Science and Engineering, Hubei University of Automotive Technology, Shiyan 442002, China
关键词:
DP980超高强钢 激光焊接 软化 不均匀变形 力学性能
Keywords:
ultra-high strength steel DP980 laser welding softening inhomogeneous deformation mechanical properties
分类号:
TG456.7
DOI:
10.11784/tdxbz201511002
文献标志码:
A
摘要:
利用Nd:YAG固体激光器对DP980超高强钢进行激光对接焊接, 通过硬度测试、拉伸试验研究DP980超高强钢激光焊接接头力学性能的变化, 采用光学显微镜(OM)、扫描电子显微镜(SEM)等观察显微组织的转变.结果表明:DP980超高强钢经过激光焊接, 焊接接头分为焊缝金属区、完全相变区、不完全相变区、回火区和母材区.焊后焊缝金属区和完全相变区为马氏体组织, 硬度较高; 焊接接头软化现象发生在不完全相变区和回火区:不完全相变区马氏体发生相变使得铁素体含量增加; 回火区组织发生回火, 马氏体析出碳化物, 导致软化.在力学性能方面, 焊接接头抗拉强度略有降低, 延伸率下降明显, 软化区的存在导致在拉伸试验时焊接接头的不均匀变形, 造成了其塑性明显下降; 拉伸试样的断裂发生在焊接接头热影响区, 断口观察发现存在有大小不等、深浅不一的韧窝, 属于塑性断裂.
Abstract:
Ultra-high strength steel DP980 was welded employing Nd: YAG laser. The mechanical properties of welded joints were investigated through hardness test and tensile test,and the evolution of microstructures was observed through optical microscope(OM)and scanning electron microscope(SEM). The results showed that laser-welded DP980 joints could be divided into weld metal(WM) zone,complete phase-transformation zone,incomplete phase-transformation zone,tempered zone and base metal(BM) zone. The weld metal zone and complete phase-transformation zone consisted of martensite,exhibiting higher hardness. The softening of welded joints occurred in incomplete phase-transformation zone and tempered zone. In incomplete phase-transformation zone,the ferrite content increased because of transformation of martensite while in tempered zone carbide precipitated in martensite due to tempering. In terms of mechanical properties,the welded joints witnessed a slight decrease in tensile strength and an obvious decrease in elongation rate due to the inhomogeneous deformation originating from softening of welded joints. The tensile tests revealed that fracture took place in heat-affected zone(HAZ),presenting the characteristics of plastic fracture and different sizes of dimples.

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备注/Memo

备注/Memo:
收稿日期: 2015-11-02; 修回日期: 2015-12-07.
作者简介: 杨立军(1966—), 男, 博士, 教授, yljabc@tju.edu.cn.
通讯作者: 孙明升, famousman@tju.edu.cn.
网络出版时间: 2016-03-10.网络出版地址: http://www.cnki.net/kcms/detail/12.1127.N.20160310.0904.004.html.
基金项目: 国家自然科学基金资助项目(51175374); 先进焊接与连接国家重点实验室开放基金资助项目(AWJ-Z15-03).
Supported by the National Natural Science Foundation of China(No. 51175374)and the Foundation of the State Key Laboratory of Advanced Welding and Joining(No. AWJ-Z15-03).
更新日期/Last Update: 2017-03-10