| Q690C低碳粒贝钢多层MAG焊接头组织与性能 |
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| 引用本文： | 郭咏华,张贵锋,杨宗奇,黄超.Q690C低碳粒贝钢多层MAG焊接头组织与性能[J].焊接学报,2015,36(1):96-100. |
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| 作者姓名： | 郭咏华 张贵锋 杨宗奇 黄超 |
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| 作者单位： | 1.河南省电力勘测设计院, 郑州 450007 |
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| 摘 要： | 为提高效率、获得理想断裂位置并改善热影响区韧性,对控扎控冷工艺生产的8 mm厚Q690C低碳粒贝钢,选用等强度匹配的焊丝,采用无预热、低热输入(10 kJ/cm以下)三层全自动MAG工艺施焊.结果表明,无裂纹与成形缺陷;拉、弯与冲击性能均合格.焊缝为针状铁素体,韧性优异;仅在较窄的部分相变区(单道约0.2~0.4 mm)因回火而出现软化,但未对抗拉性能形成危害;因热输入低,拉伸断裂位置距焊缝更远;虽然熔合区与粗晶区为粗大平行上贝板条束+M-A组元,出现了硬化,但低热输入的低过热效果与两次后续焊道对贝氏体基体的明显回火作用改善了熔合区在0℃的冲击韧性.
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| 关 键 词： | Q690C低合金高强钢 等匹配 低碳贝氏体 全自动MAG焊 贝氏体回火 |
| 收稿时间： | 2013/6/25 0:00:00 |
Microstructure and mechanical property of Q690C HSLA steel joint welded by multipass metal active gas (MAG) welding process |
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| GUO Yonghu,ZHANG Guifeng,YANG Zongqi and HUANG Chao.Microstructure and mechanical property of Q690C HSLA steel joint welded by multipass metal active gas (MAG) welding process[J].Transactions of The China Welding Institution,2015,36(1):96-100. |
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| Authors: | GUO Yonghu ZHANG Guifeng YANG Zongqi and HUANG Chao |
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| Affiliation: | 1.Henan Electric Power Survey & Design Institute, Zhengzhou 450007, China2.Institute of Welding Research, State key Laboratory of Xi'an Jiaotong University, Xi'an 710049, China |
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| Abstract: | To increase productivity and improve joint property, 8 mm thick high-strength low-alloy structural steel of Q690C supplied in TMCP condition was welded with 3 pass metal active gas (MAG) welding at low heat input (10 kJ/cm) using equal-matched welding wire without preheating. The joint macrostructure, microstructure and mechanical property were investigated. The results show that no crack and defects were observed, and joint tensile, bending and impact properties are qualified. Each weld metal was acicular ferrite, which had excellent impact toughness. Although intercritical heat affected zone (ICHAZ) became soft due to temper of the base metal, the resultant harmful effect on tensile property was inhibited due to its smaller width (0.2-0.4 mm for one pass). The joint not only at the location further away from fusion line, but also exhibited a passed impact toughness at 0℃, even at coarse grained heat affected zone (CGHAZ) with lath beam microstructure of coarse upper bainite and M-A constituent. The former can be attributed to the lower heat input, which can reduce softening degree. The latter can be attributed to (i) the lower heat input which can reduce the effective grain size (length of lath bainite) of CGHAZ and the fusion zone (consisting of coarse upper bainite lath and M-A constituent) and (ii) temper of bainite by subsequent welding passes. |
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| Keywords: | Q690 HSLA equal-matched low carbon bainitic steel full-automatic metal active gas welding temper of bainite |
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