| 摘要: |
| 采用焊条电弧焊的方法对7N01铝合金焊接试板进行TIG熔修,对熔修前后的试件进行疲劳寿命测试,并对焊接接头的显微硬度变化进行测试,采用扫描电镜对疲劳断口进行显微形貌分析,并对疲劳源区缺陷进行XRD成分检测.结果表明,TIG熔修对焊趾应力集中的降低有限,还可能引入新的焊接缺陷成为疲劳裂纹源;同时TIG熔修使得焊接区域经受二次加热,沉淀强化相的形态和重新分布造成接头组织弱化,降低了焊接接头抵抗疲劳裂纹扩展的能力,多方面作用的结果是:经TIG熔修后铝合金焊接接头疲劳寿命略有降低,所以对于7N01高强铝合金对接接头单纯采用焊趾TIG熔修的方法提高疲劳性能不具备可行性. |
| 关键词: TIG熔修 疲劳 焊接接头 |
| DOI： |
| 分类号: |
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| Effect of TIG-dressing on fatigue properties of 7N01 aluminium alloy welded joint |
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YAN Zhongjie1, LIU Xuesong1, FANG Hongyuan1, WANG Ping1, WANG Ren2, MENG Lichun2
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1.State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China;2.CSR Sifang Locomotive and Rolling Stock Co., Ltd, Qingdao 266111, China
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| Abstract: |
| TIG-dressing of 7N01 aluminium alloy welded joint was carried out by shielded metal arc welding.The fatigue properties and microhardness of specimens were tested before and after TIG-dressing,and the fractography was analyzed with SEM and the composition in defect zone was examined with XRD.Experimental results show that TIG-dressing slightly reduced the stress concentration on the weld toe,however,TIG-dressing could also bring additional weld defects which would initiate fatigue crack.The reheating by TIG-dressing could soften the welded joint and degrade the resistance to fatigue crack propagation.Consequently,the fatigue life of welded joint after TIG-dressing slightly decreased.Therefore,it had no feasibility to improve the fatigue properties of 7N01 high strength aluminium alloy welded joint by TIG-dressing. |
| Key words: TIG-dressing fatigue welded joint |
