材料工程与机械制造

辅助加热温度对铝合金厚板FSW焊缝成形的影响

  • 毛育青 ,
  • 赵艺达 ,
  • 江周明 ,
  • 柯黎明
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  • 南昌航空大学 轻合金加工科学与技术国防重点学科实验室, 南昌 330063

收稿日期: 2018-07-18

  修回日期: 2018-08-06

  网络出版日期: 2018-09-19

基金资助

江西省教育厅科技项目(DA201803145);轻合金加工科学与技术国防重点学科实验开放基金(EG201703503);无损检测技术教育部重点实验室开放基金(EW201703508);南昌航空大学博士科研启动基金(EA201803212)

Effect of assisted preheating temperature on weld formation of FSW of aluminum alloy thick plates

  • MAO Yuqing ,
  • ZHAO Yida ,
  • JIANG Zhouming ,
  • KE Liming
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  • National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China

Received date: 2018-07-18

  Revised date: 2018-08-06

  Online published: 2018-09-19

Supported by

Department of Education Science and Technology Project in Jiangxi province (DA201803145); Fund Projects of National Defence Key Discipline Laboratory of Light Alloy Processing Science (EG201703503); Fund Projects of Technology and Key Laboratory of Nondestructive Testing, Ministry of Education (EW201703508); Ph.D. Research Foundation Project of Nanchang Hangkong University (EA201803212).

摘要

对铝合金厚板搅拌摩擦焊(FSW)而言,焊缝底部金属温度低、流动能力差是导致焊缝成形困难的主要原因。为此,本研究采用辅助加热的方式对待焊母材底部进行预热,分析辅助加热温度对厚板搅拌摩擦焊焊缝成形的影响。结果表明,随着辅助加热温度从20℃升高至80℃时,焊缝成形质量先变好后变差,宏观表现为焊缝内部焊核区宽度、高度及面积呈现先增大后减小的趋势,而疏松区面积呈现先减小后增大的趋势。其中,当辅助加热温度为40℃时,焊缝成形质量最好,焊核区尺寸最大,疏松区消失;而当辅助加热温度升高至80℃时,焊缝成形质量最差,疏松区面积最大。研究认为,其主要原因是添加合适的辅助加热温度可显著提高焊核区塑性金属的峰值温度及高温停留时间,塑性金属流动能力明显提高,焊缝成形质量得到极大改善。焊核区塑性金属的迁移方式由沿搅拌针表面向焊缝上部高温区迁移向挤压焊核区周边冷金属横向迁移转变。但是,当辅助加热温度太高时,焊核区塑性金属迁移方式开始转变为原始的沿搅拌针表面向焊缝上部高温区迁移,且此迁移程度有明显增大的趋势,导致焊缝内部疏松区缺陷再次出现。

本文引用格式

毛育青 , 赵艺达 , 江周明 , 柯黎明 . 辅助加热温度对铝合金厚板FSW焊缝成形的影响[J]. 航空学报, 2018 , 39(12) : 422554 -422554 . DOI: 10.7527/S1000-6893.2018.22554

Abstract

For Friction Stir Welding (FSW) of aluminum alloy thick plates, the main reasons of poor weld formation quality are the low temperature of plastic metal in the weld root and its low flowability. Therefore, the assisted heating method was used to preheat the thick plate bottom in this study, and the effect of assisted preheating temperature on weld formation of FSW of thick plates was investigated. The results show that, with the assisted preheating temperature increasing from 20℃ to 80℃, the weld quality improves firstly and then worsens In particular, the width, height and area of nugget zone in the weld show a bulge trend. However, the area of loose zone shrinks first and then expands. When the assisted preheating temperature reaches 40℃, the produced weld has the best quality and the largest size of the nugget zone with the loose zone disappearing into the weld. However, when the assisted preheating temperature raises to 80℃, the obtained weld is the worst and the area of the loose zone is the largest. The study finds that, the enhancement of the flowability and the weld quality are mainly caused by significantly raising the peak temperature and extending high temperature acting time when an appropriate assisted preheating temperature is applied.. The flow pattern of plastic materials in the nugget zone transfers from flowing upward to high temperature zone on the weld top along the rotating pin surface to transverse flow of extruding surrounding cold metal. Nonetheless, when the assisted preheating temperature is too high, the flow pattern of plastic materials in the nugget zone starts to transform into original mode of flowing upward to high temperature zone on the weld top along the rotating pin surface. Also, this transferring degree increases evidently, causing the reappearance of the defects in the loose zone.

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