X80埋弧焊热影响区的微观组织与局部软化行为分析

朱敏; 张延松

doi:10.12073/j.hjxb.20200929002

X80埋弧焊热影响区的微观组织与局部软化行为分析

朱敏,
张延松^,

上海交通大学，上海市复杂薄板结构数字化制造重点实验室，上海，200240

基金项目: 工信部高技术船舶科研资助项目(MC-201906-Z01)

详细信息

作者简介:
朱敏，博士研究生；主要研究方向为焊接接头的组织及性能分析；E-mail：zhumin118hai@sjtu.edu.cn.

通讯作者:
张延松，教授，博士研究生导师；E-mail：zhangyansong@sjtu.edu.cn.

中图分类号: TG 453.9
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出版历程
- 收稿日期: 2020-09-28
- 网络出版日期: 2021-04-14
- 刊出日期: 2021-04-24

Analysis of microstructure and local softening of heat-affected zone of submerged-arc welded X80 joint

ZHU Min,
ZHANG Yansong^,

Shanghai Key Laboratory of Digital Manufacture for Thin-Walled Structures, Shanghai Jiao Tong University, Shanghai 200240, China

摘要

摘要: 以X80高等级管线钢埋弧焊接头作为研究对象，利用小尺寸拉伸样配合数字图像相关技术(DIC)对其热影响区的局部软化现象和失效行为做了表征，研究接头热影响区的强度退化和组织演变之间的关系. 应用数字图像相关技术的拉伸应变云图表明，单道焊热影响区内的一次细晶区(FGHAZ)及两道焊交叠热影响区内的二次细晶亚区(UAFZHAZ和ICFGHAZ)均发生了明显的软化现象. 微观组织表征结果表明，微区内部位错缠结、位错墙等亚结构消失导致的位错强化效果的下降和M/A组元形态及数量变化导致的析出强化效果的减弱是软化发生的主要原因；在两道焊交叠热影响区，二次细晶亚区的局部软化可以被周围的其它区域有效缓和，对接头的安全服役威胁较小，相比之下，一次细晶区的强度退化更值得关注.
- 热影响区 /
- 数字图像相关技术 /
- 局部软化 /
- 位错 /
- M/A组元
Abstract: X80 pipeline steel was welded by submerged arc welding process. The local softening phenomenon and failure behavior of heat-affected zone (HAZ) of the welding joint were characterized by digital image correlation (DIC) tensile tests using mini-sized flat specimens. The relationship between strength degradation and microstructural evolution was discussed carefully. The DIC results show that the primary fine-grain heat-affected zone (FGHAZ) and the secondary heat-affected zone (UAFZHAZ and ICFGHAZ) are both the softening areas in HAZ of joint. The microstructural characterization shows that the softening is mainly attributed to the dislocation strengthening weakening resulting from the decreasing of dislocation tangles and dislocation walls and the precipitation strengthening weakening due to the changes in form and quantity of M/A. But, the softening of secondary heat affected zone can be effectively alleviated by other surrounding regions which is favorable to joint. On the contrary, the strength degradation of the primary heat affected zone has a greater threat to the service safety of welded joints.
- heat affected zone /
- DIC /
- local softening /
- dislocation /
- M/A

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图 1 焊缝宏观形貌及微区拉伸样的取样方式示意图

Figure 1. Macro-morphology of welding seam and the sampling schematic diagram of DIC tensile tests

下载: 全尺寸图片幻灯片

图 2 不同热影响区样品的DIC拉伸结果

Figure 2. The DIC tensile test results. (a) primary HAZ; (b) secondary HAZ; (c) the initial and fractured samples of primary HAZ; (d) the initial and fractured samples of secondary HAZ; (e) tensile curves of samples

下载: 全尺寸图片幻灯片

图 3 热影响区的扫描组织

Figure 3. The microstructure of HAZ. (a) CGHAZ (first pass); (b) CGHAZ (second pass); (c) FGHAZ; (d) ICCGHAZ

下载: 全尺寸图片幻灯片

图 4 焊接热影响区的透射组织

Figure 4. The TEM microstructure of HAZ. (a) CGHAZ (first pass); (b) ICCGHAZ; (c) FGHAZ (first pass); (d) ICFGHAZ

下载: 全尺寸图片幻灯片

表 1 试验所采用的X80钢材及焊丝的化学成分 (wt.%)

Table 1 The composition of X80 pipeline steel and the corresponding welding wire

C Mn Si P S Cu + Cr + Ni + Mo + Nb + V Fe

X80母材 0.046 1.75 0.20 0.005 0.000 4 0.58 余量
埋弧焊丝 0.04 1.85 0.35 0.003 0.002 0.49 余量

下载: 导出CSV

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