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摘要: 針對穿孔深熔氬弧焊(K-TIG)工藝焊接8 mm厚Q235低碳鋼板時焊接過程不穩定、焊接工藝窗口小等突出問題，首次提出在焊接工件背部鋪加保護焊劑的方法改善焊接過程。采用對接焊的方式，在不開坡口、焊接過程不添加焊絲的情況下，達到單面焊雙面成形的效果。最終成功的采用430～480 A范圍內的直流電流對8 mm厚的Q235低碳鋼進行了焊接，將焊接電流窗口擴大到50 A同時也顯著的提高了焊接過程的穩定性。同時，在擴大焊接電流窗口之后，系統研究了不同焊接電流下焊接接頭的組織性能。研究結果表明：在不同焊接電流下得到的焊接接頭中，組織分布以及力學性能分布呈現出相同的狀態。焊縫區的組織均由鐵素體+珠光體+魏氏組織組成；熔合區由魏氏組織組成；熱影響區由鐵素體+少量的珠光體組成；此外隨著焊接電流的增加，焊接接頭背部的熔寬有略微增加；在焊接接頭中，熔合區處硬度值最高，其次是焊縫區，之后是熱影響區，母材的硬度值最低；焊接接頭最終的拉伸斷裂位置是在熱影響區處。Abstract: The welding of 8-mm thick Q235 low-carbon steel plates by keyhole tungsten inter gas welding (K-TIG), a deep penetration argon arc welding technique with tungsten electrode, is associated with many problems, including an unstable welding process and a small welding current window. To solve these prominent problems, the method of adding shielding flux on the back of the welding workpieces was proposed for the first time in this paper. This method can improve the stability of the welding process. The butt welding method was used to achieve the result of single-sided welding and double-sided forming without adding welding wire or prefabricating groove during the welding process. The results show that direct current (DC) in the range of 430–480 A is successfully used to weld the 8-mm thick Q235 low-carbon steel. The welding current window is expanded to 50 A, and the welding process stability is significantly improved. After expanding the welding current window, the microstructures and properties of welded joints obtained under different welding currents were systematically studied. The results show that the distribution of microstructures and the mechanical properties of the welded joints under different welding currents present the same states. The microstructures of the weld zone are composed of ferrite + pearlite + widmanstatten structure; the microstructures of the fusion zone are composed of Widmanstatten structure; the structures of the heat-affected zones are composed of ferrite + a small amount of pearlite. In addition, with the increase in the welding current, the fusion width of the back of the workpiece increased slightly. In the welding joint, the hardness value of the fusion zone is the highest, followed by the weld zone, and the heat-affected zone. The base material has the least hardness, and the final tensile fracture position of the welded joint is in the heat affected zone.
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Key words:
- low-carbon steel /
- process window /
- welding flux /
- K-TIG /
- joint microstructure
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圖 2 焊接接頭表面外觀形貌。（a）焊接接頭正面成形；（b）焊接接頭背面成形
Figure 2. Surface appearance of the welded joints: (a) front forming of welded joints; (b) back forming of welded joints
圖 6 焊縫區微觀組織。（a）鐵素體+珠光體；（b）魏氏體組織
Figure 6. Microstructure of weld zone: (a) ferrite + pearlite; (b) widmanstatten
表 1 Q235鋼的化學成分（質量分數）%
Table 1. Chemical composition of the Q235
C Mn Si S P Fe 0.17 1.48 0.35 0.08 0.21 Bal. 
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中文字幕在线观看表 2 K-TIG焊接參數
Table 2. K-TIG welding parameters
Welding voltage/
VWelding speed/
(mm·s?1)Distance between tungsten electrode
and test plate/mmTungsten tip angle /
(°)Type of tungsten
electrodeDiameter of tungsten
electrode/mm20 5 2.5 90 Lanthanum tungsten 6
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參考文獻
[1] Hui L, Liu S Q, Zhou S, et al. Influence of loading direction and weld reinforcement on fatigue performance of TIG weld seam. J Mater Eng, 2018, 46(2): 122 doi: 10.11868/j.issn.1001-4381.2016.001177回麗, 劉思奇, 周松, 等. 載荷方向和焊縫余高對氬弧焊縫疲勞性能的影響. 材料工程, 2018, 46(2):122 doi: 10.11868/j.issn.1001-4381.2016.001177 [2] Dhib Z, Guermazi N, Gaspérini M, et al. Cladding of low-carbon steel to austenitic stainless steel by hot-roll bonding: microstructure and mechanical properties before and after welding. Mater Sci Eng A, 2016, 656: 130 doi: 10.1016/j.msea.2015.12.088 [3] Saha M K, Hazra R, Mondal A, et al. Effect of heat input on geometry of austenitic stainless steel weld bead on low carbon steel. J Inst Eng (India)Ser C, 2019, 100(4): 607 doi: 10.1007/s40032-018-0461-7 [4] Huang Z J, Liu J B, Miao K, et al. Study on the strength of medium steel plate welding. Electr Weld Machine, 2010, 40(7): 49 doi: 10.3969/j.issn.1001-2303.2010.07.011黃治軍, 劉吉斌, 繆凱, 等. 中等厚度板埋弧焊焊縫研究. 電焊機, 2010, 40(7):49 doi: 10.3969/j.issn.1001-2303.2010.07.011 [5] Biswas P, Mandal N R, Saravanan M, et al. Experimental study on square-butt single-pass single-side submerged arc welding of low-carbon microalloyed steel. J Ship Prod Des, 2009, 25(2): 109 [6] Yin R X. Study on submerged arc welding process for 20Mn23Al No magnetic steel and Q235 low carbon steel. Hot Working Technol, 2011, 40(19): 156 doi: 10.3969/j.issn.1001-3814.2011.19.052殷榮幸. 20Mn23Al無磁鋼與Q235低碳鋼的埋弧焊焊接工藝. 熱加工工藝, 2011, 40(19):156 doi: 10.3969/j.issn.1001-3814.2011.19.052 [7] Zhou S L, Tao J, Guo D L. Study on microstructure and mechanical properties of fine grain TC21 alloy in TIG. J Aeron Mater, 2009, 29(6): 53 doi: 10.3969/j.issn.1005-5053.2009.6.011周水亮, 陶軍, 郭德倫. TC21細晶鈦合金TIG焊接接頭組織及力學性能研究. 航空材料學報, 2009, 29(6):53 doi: 10.3969/j.issn.1005-5053.2009.6.011 [8] Rosellini C, Jarvis L. The keyhole TIG welding process: a valid alternative for valuable metal joints. Weld Int, 2009, 23(8): 616 doi: 10.1080/09507110802543237 [9] Fei Z Y, Pan Z X, Cuiuri D, et al. Investigation into the viability of K-TIG for joining armour grade quenched and tempered steel. J Manuf Processes, 2018, 32: 482 doi: 10.1016/j.jmapro.2018.03.014 [10] Feng Y Q, Luo Z, Liu Z M, et al. Keyhole gas tungsten arc welding of AISI 316L stainless steel. Mater Des, 2015, 85: 24 doi: 10.1016/j.matdes.2015.07.011 [11] Fan W F, Ao S S, Huang Y F, et al. Water cooling keyhole gas tungsten arc welding of HSLA steel. Int J Adv Manuf Technol, 2017, 92(5-8): 2207 doi: 10.1007/s00170-017-0234-0 [12] Huang Y F, Luo Z, Lei Y C, et al. Dissimilar joining of AISI 304/Q235 steels in keyhole tungsten inert gas welding process. Int J Adv Manuf Technol, 2018, 96(9-12): 4041 doi: 10.1007/s00170-018-1791-6 [13] Xie Y, Cai Y C, Zhang X, et al. Characterization of keyhole gas tungsten arc welded AISI 430 steel and joint performance optimization. Int J Adv Manuf Technol, 2018, 99(1-4): 347 doi: 10.1007/s00170-018-2257-6 [14] Olivares E A G, e Silva R H G, Dutra J C. Study of keyhole TIG welding by comparative analysis of two high-productivity torches for joining medium-thickness carbon steel plates. Weld Int, 2017, 31(5): 337 doi: 10.1080/09507116.2016.1218603 [15] Liang J D, Guo S M, Wahab M A. Localized surface modification on 1018 low-carbon steel by electrolytic plasma process and its impact on corrosion behavior. J Mater Eng Perform, 2014, 23(12): 4187 doi: 10.1007/s11665-014-1165-7 [16] Zhang R H, Fan D. Weldability of activating flux in A-TIG welding for mild steel. Trans China Weld Inst, 2003, 24(1): 85 doi: 10.3321/j.issn:0253-360X.2003.01.022張瑞華, 樊丁. 低碳鋼A-TIG焊活性劑的焊接性. 焊接學報, 2003, 24(1):85 doi: 10.3321/j.issn:0253-360X.2003.01.022 -
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