980MPa高强钢TIG焊接接头原位拉伸断裂机理

中国机械工程 ›› 2010, Vol. 21 ›› Issue (22): 2746-2750.

980MPa高强钢TIG焊接接头原位拉伸断裂机理

张晓波1;曹睿1;冯伟2;彭云3;江峰4;陈剑虹1

1.兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州,730050

2.哈尔滨焊接研究所,哈尔滨,150080;

3.钢铁研究总院,北京,100081

4.西安交通大学金属材料强度国家重点实验室,西安,710049

出版日期:2010-11-25 发布日期:2010-12-01
基金资助:
国家自然科学基金资助项目(50905081，50671047)；国家高科技研究发展计划(863计划)资助项目(2006AA03206)；西安交通大学金属材料强度国家重点实验室开放研究项目(201011001)
National Natural Science Foundation of China（No. 50905081，50671047）;

National High-tech R&D Program of China (863 Program) （No. 2006AA03206）

Fracture Mechanism of In-situ Tensile of TIG Welding Joints for 980MPa High Strength Steels

Zhang Xiaobo1;Cao Rui1;Feng Wei2;Peng Yun3;Jiang Feng4;Chen Jianhong1

1.State Key Laboratory of Advanced Non-ferrous Metal Materials,Lanzhou University of Technology,Lanzhou,730050

2.Harbin Welding Institute,Harbin,150080

3.Central Iron and Steel Research Institute,Beijing,100081

4.State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an,710049

Online:2010-11-25 Published:2010-12-01
Supported by:

National Natural Science Foundation of China（No. 50905081，50671047）;

National High-tech R&D Program of China (863 Program) （No. 2006AA03206）

摘要/Abstract

摘要：

对新型980MPa深海用高强钢TIG焊接接头5种不同缺口位置的试样进行了原位拉伸试验,通过试验观察了每个试样的动态断裂过程，并对其断裂机理进行了详细研究和分析，最终确定焊接接头的薄弱环节。试验结果表明:直缺口试样的微观断裂经历了塑性变形、缺口处起裂、裂纹扩展、裂纹尖端钝化，直至试样断裂的过程，并且在裂纹扩展过程中，裂纹尖端重复钝化、扩展、新裂纹产生、再钝化、再扩展的过程;圆弧试样和平板试样在剪切力的作用下经历塑性变形、颈缩、出现微裂纹、微裂纹扩展，直至试样瞬间断裂的过程，并且圆弧试样和平板试样的起裂应力和断裂应力十分接近，表现为突发形式;平板试样中发现最后断裂在焊缝金属处，这说明其薄弱环节为焊缝金属处。

关键词:

贝氏体钢, TIG焊, SEM原位拉伸, 断裂机理

Abstract:

In-situ tensile tests of welding joints of bainite high strength steels with notch specimens were studied.Fracture processes of welding joints of this high strength steel were observed by in-situ tensile tests,and fracture mechanism was also analyzed.By

these studies, the weak link of welding joints was determined.It is found that:plastic deformation is produced at notch tips with applied load increasing.For slight notch specimens, plastic deformation appears at the notch root, a short plastic crack is initiated, propagated, blunted and repeated process are done, finally, the specimens are fractured along notch root. For the specimens with a large arc, at the action of shear stress, plastic deformation appears firstly, and necking are produced, then microcracks are initiated and

propagated. The processes are repeated until the specimen fracture. Initiated stress and fracture stress are almost the same for large arc specimens and smooth specimens, so sudden fracture are produced. In the smooth tensile specimens, fracture is produced at weld metals zone, so weld metals are the weak link of welding joints.

Key words: bainite steel, TIG welding, SEM in situ tensile, fracture mechanism

中图分类号:

TG301]

张晓波, 曹睿, 冯伟, 彭云, 江峰, 陈剑虹.

980MPa高强钢TIG焊接接头原位拉伸断裂机理

[J]. 中国机械工程, 2010, 21(22): 2746-2750.

ZHANG Xiao-Bei, CAO Rui, FENG Wei, BANG Yun, JIANG Feng, CHEN Jian-Gong.

Fracture Mechanism of In-situ Tensile of TIG Welding Joints for 980MPa High Strength Steels

[J]. China Mechanical Engineering, 2010, 21(22): 2746-2750.

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