Research on Novel Soft Variable Polarity Plasma Arc Welding Technology for Aluminum Alloys in Horizontal Position

doi:10.3901/JME.2015.24.075

Abstract

Abstract: Considering the imperative need of horizontal welding technology for aluminum alloys with medium thickness and its bottleneck problems, keyhole mode variable polarity plasma arc(VPPA) welding technology is studied. Ordinary VPPA horizontal welding experiments for aluminum alloy thickness 8 mm plates are carried out. It is found that the keyhole is very difficult to be established. The forces acting on keyhole and the fluid flow in weld pool are analyzed to seek the cause of the problem. An inequality equation is induced to describe the relationship of surface tension, arc pressure and the gravity. When the inequality equation is satisfied, the closure of keyhole can be achieved. Based on the above theory, a novel soft VPPA is proposed. Under the keyhole mode welding condition, the decrease of arc pressure makes the critical radius of keyhole on back side larger and promotes the stable establishment of keyhole. Using this novel technology, keyhole mode horizontal welding of 2219 aluminum alloy plates thickness 8mm is achieved and its weld formation is very good. Porosity welding defect can be eliminated mostly by preheating method and scraping oxide film before welding.

Key words: aluminum alloy, arc pressure, horizontal position welding, soft arc, stability of keyhole

ZHANG Qinlian, YANG Chunli, LIN Sanbao, SUN Shixuan, LI Zhanhui, LIU Zheng, JIANG Yukang, LIU Juan, MA Jianbo. Research on Novel Soft Variable Polarity Plasma Arc Welding Technology for Aluminum Alloys in Horizontal Position[J]. Journal of Mechanical Engineering, 2015, 51(24): 75-81.

References

[1] 刘欣，王国庆，李曙光，等. 重型运载火箭关键制造技术发展展望[J]. 航天制造技术，2013(1)：1-6. LIU Xin，WANG Guoqing，LI Shuguang，et al. Forecasts on crucial manufacturing technology development of heavy lift launch vehicle[J]. Aerospace Manufacturing Technology，2013(1)：1-6.
[2] 陈克选，李鹤岐，李春旭. 变极性等离子弧焊研究进展[J]. 焊接学报，2004，25(1)：124-128. CHEN Kexuan，LI Heqi，LI Chunxu. Progress in variable polarity plasma arc welding[J]. Transactions China Welding Institution，2004，25(1)：124-128.
[3] TOMSIC M，BARHORST S. Keyhole plasma arc welding of aluminum with variable polarity power[J]. Welding Journal，1984：63(2)：25-32.
[4] NUNES A C. Variable polarity plasma arc welding on the space shuttle external tank[J]. Welding Journal，1984，63：27-35.
[5] CAMPBELL S W，GALLOWAY A M，MCPHERSON N A. Arc pressure and weld metal fluid flow while using alternating shielding gases. Part 1：Arc pressure measurement[J]. Science and Technology of Welding and Joining，2013，18(7)：591-596.
[6] ZHANG Q L，YANG C L，LIN S B，et al. Horizontal welding of aluminium alloys by soft plasma arc[J]. Proceedings of the Institution of Mechanical Engineers Part B：Journal of Engineering Manufacture，2014，228(11)：1481-1490.
[7] 张勤练，杨春利，林三宝，等. 2A14铝合金变极性等离子横向焊缝成形特点[J]. 焊接学报，2013，34(9)：79-82. ZHANG Qinlian，YANG Chunli，LIN Sanbao，et al. Characteristics of weld formation in variable polarity plasma arc horizontal welding of 2A14 aluminum alloy[J]. Transactions China Welding Institution，2013，34(9)：79-82.
[8] 韩永全，陈树君，殷树言，等. 大厚度铝合金变极性等离子弧穿孔立焊技术[J]. 机械工程学报，2006，42(9)：144-148. HAN Yongquan，CHEN Shujun，YIN Shuyan，et al. Variable polarity plasma arc welding process for thick aluminum alloy[J]. Chinese Journal of Mechanical Engineering，2006，42(9)：144-148.
[9] 吕耀辉，陈树君，殷树言，等. 维弧对铝合金变极性穿孔型等离子弧行为的影响[J]. 机械工程学报，2003，39(11)：141-143. LÜ Yaohui，CHEN Shujun，YIN Shuyan，et al. Effect of pilot arc on the behavior of variable polarity plasma arc used in welding aluminum[J]. Chinese Journal of Mechanical Engineering，2003，39(11)：141-143.
[10] 王后孝，杨春利，魏艳红，等. 变极性等离子弧立焊穿孔熔池的稳定建立[J]. 机械工程学报，2007，42(12)：59-64. WANG Houxiao，YANG Chunli，WEI Yanhong，et al. Establishment of stable keyhole pool during variable polarity vertical-up plasma arc welding process[J]. Chinese Journal of Mechanical Engineering，2007，42(12)：59-64.

[1]	LIN Zhixiong, SHAO Zhen, LIANG Xinyu, CUI Lei, WANG Dongpo, XIE Yan, HUANG Yiming, YANG Lijun. Analysis of the Formation Process of AA 2219-T87 Friction Pull Plug Welding [J]. Journal of Mechanical Engineering, 2024, 60(20): 144-152.
[2]	WANG Gang, GU Zhengwei, YU Ge, LI Xin. Plastic Flow Behavior and Constitutive Model of 7075-H18 Aluminum Alloy Sheet Based on Hot Forming Process [J]. Journal of Mechanical Engineering, 2024, 60(2): 188-196.
[3]	WANG Xiangyu, QIU Wenhao, NIU Jintao, LIU Guoliang, FU Xiuli, GUO Peiquan, QIAO Yang. Simulation and Experimental Study on Temperature in Cryogenic Cutting of Titanium Aluminum Alloy [J]. Journal of Mechanical Engineering, 2024, 60(19): 318-331.
[4]	ZHANG Huijie, KONG Xuliang, YAO Enze, MA Kang, SONG Jianling. Affecting Mechanism of Base Metal’s Relative Position on Microstructure and Property of Dissimilar Friction Stir Welded Joint of High-strength Aerospace Aluminum Alloys [J]. Journal of Mechanical Engineering, 2024, 60(18): 154-162.
[5]	YANG Xiawei, MENG Tingxi, CHU Qiang, FAN Wenlong, SU Yu, MA Tiejun, LI Wenya. Research Progress in Double-sided Friction Stir Welding of Aluminum Alloy [J]. Journal of Mechanical Engineering, 2024, 60(14): 77-96.
[6]	WANG Hao, LIU Kun, LI Jie, YU Wenming, WU Hong, OKULOV Artem. Research Progress on Solidification Cracking of Aluminum Alloy During Welding and Crack Resistance of Filler Materials [J]. Journal of Mechanical Engineering, 2024, 60(12): 207-219.
[7]	CHEN Rui, CHENG Shimin, WEN Shicheng, ZHAO Ziheng, PENG Ruitao, HU Congfang, XIAO Xiangwu. Structural Optimization of 7150-T6 Aeronautical Aluminum Alloy Thin-walled Open Circular Tube Based on J-C Model Modification [J]. Journal of Mechanical Engineering, 2024, 60(11): 95-104.
[8]	GAO Zhuanni, WANG Leilei, LI Xiang, LIU Zhiqiang, Lü Feiyue, LI Yifan, ZHAN Xiaohong. Effect of Thermal Cycle and Temperature Gradient on Solidification Microstructure of Deposition Layer during 7075 Aluminum Alloy Laser Wire Additive Manufacturing [J]. Journal of Mechanical Engineering, 2024, 60(1): 96-118.
[9]	CHEN Yu, LIU Wen-wen, WANG Tao, SHEN Hong-zhuo, CHEN Ke, ZHANG Bin. Study on Influence Mechanism of Prefabricating Corrugation Process on Interface of Steel/Aluminum/Aluminum Alloy Laminated Plate [J]. Journal of Mechanical Engineering, 2023, 59(8): 74-82.
[10]	ZHOU Dan, WANG Pengcheng, ZHANG Tengfei, SONG Shouxu. Correlation Between the Color Difference and Joint Performance of Recycling ZL101A Alloy Repaired by TIG [J]. Journal of Mechanical Engineering, 2023, 59(7): 398-406.
[11]	CHEN Xin, WANG Jianing, YANG Lifei, ZHANG Guanchen. Shear Specimens and Dynamic Shear Mechanical Properties of 6061-T6 Aluminum Alloy Sheets [J]. Journal of Mechanical Engineering, 2023, 59(4): 62-70.
[12]	ZHANG Hanyu, SONG Zhouzhou, LIU Zhao, ZHU Ping. Research on Reliability of Mechanical Properties of Carbon Fiber Reinforced Plastics and Aluminum Alloy Hybrid Joints [J]. Journal of Mechanical Engineering, 2023, 59(24): 334-343.
[13]	LIU Yongda, XU Jie, SHAN Debin, GUO Bin. Tool Deflection Analysis and Optimization of Porthole Die for Micro Heat Pipe in Aluminum Alloy [J]. Journal of Mechanical Engineering, 2023, 59(22): 265-274.
[14]	DUAN Liming, HONG Zhibo, CUI Junjia, LI Guangyao, JIANG Hao. Study on Electromagnetic Punching Quality of AA5182 Aluminum Alloy Sheet [J]. Journal of Mechanical Engineering, 2023, 59(12): 297-305.
[15]	FANG Jinxiu, ZHANG Xingquan, WANG Huiting, XIE Lingling. Dynamic Tensile Properties and Constitutive Model of 5052 Aluminum Alloy [J]. Journal of Mechanical Engineering, 2022, 58(8): 160-169.