槽型护轨与道岔对接的超窄间隙焊接工艺方法
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摘要
在有轨电车道岔处,需要将NM400耐磨钢槽型护轨与上部为耐磨钢、下部为低碳钢的道岔进行焊接,现采用焊剂片链约束电弧的超窄间隙焊接方法对其进行对接焊接试验。预置坡口底部宽度为4.2 mm,反变形角度为1.86°,可以保证槽型护轨与道岔焊后的平直度;在多层单道焊接过程中,根据每层焊道宽度的变化,对焊接工艺参数进行相应的调整,其中焊接电流在220～250 A变化;通过52层焊道完成了厚度为180 mm的槽型护轨对接,焊缝的宽度为4～5mm。试验结果表明,焊接接头的焊缝硬度不低于母材,焊接热影响区硬度高于母材;焊缝组织为大量的铁素体与少量的珠光体,道岔侧热影响区组织为晶粒较细的铁素体与珠光体,护轨侧热影响区组织为极细的片状珠光体。
In the turnout of the tramway, the NM400 wear-resisting steel groove type guardrails need to be welded with the turnouts which includes the wear-resisting steel on the upper part and low-carbon steel on the lower part. The butt welding test was carried out by ultra-narrow gap welding method with flux sheet chains constraining the arc. The preset width of the bottom of the groove was 4.2 mm, and the anti-deformation angle was 1.86°, which could ensure the flatness of the groove type guardrail and the turnout after welding. In the multi-layer single pass welding process, according to the change of the width of each bead, the welding process parameters were adjusted accordingly, the welding current was changed in the range of 220-250 A. The 180 mm thick groove type guardrails were welded through 52 layers of welds. The width of the weld was4-5 mm. The weld seam hardness of welded joints is not lower than that of the base metal, and the hardness of the heat-affected zone is higher than that of the base metal. The weld structure is composed of a large amount of ferrite and a small amount of pearlite, and the heat-affected zone at the side of the turnout is fine-grained and pearlite. The heat-affected zone at the side of the guardrail is very fine lamellar pearlite.
In the turnout of the tramway, the NM400 wear-resisting steel groove type guardrails need to be welded with the turnouts which includes the wear-resisting steel on the upper part and low-carbon steel on the lower part. The butt welding test was carried out by ultra-narrow gap welding method with flux sheet chains constraining the arc. The preset width of the bottom of the groove was 4.2 mm, and the anti-deformation angle was 1.86°, which could ensure the flatness of the groove type guardrail and the turnout after welding. In the multi-layer single pass welding process, according to the change of the width of each bead, the welding process parameters were adjusted accordingly, the welding current was changed in the range of 220-250 A. The 180 mm thick groove type guardrails were welded through 52 layers of welds. The width of the weld was4-5 mm. The weld seam hardness of welded joints is not lower than that of the base metal, and the hardness of the heat-affected zone is higher than that of the base metal. The weld structure is composed of a large amount of ferrite and a small amount of pearlite, and the heat-affected zone at the side of the turnout is fine-grained and pearlite. The heat-affected zone at the side of the guardrail is very fine lamellar pearlite.
引文
[1] Bajic D, Kuzmenko G V, Samard觩i I. Welding of rails with new technology of arc welding[J]. Metalurgija,2013,52(3):99-402.
[2]张佐,姜勇,巩建鸣.异种钢焊接接头碳迁移研究现状[J].热加工工艺,2014,43(7):5-9.
[3]龚练,朱亮,杨韬君.坡口宽度对超窄间隙焊接电弧特性的影响[J].兰州理工大学学报,2016,42(4):32-35.
[4]朱亮,王洪涛,符平坡.钢轨对接超窄间隙焊接试验[J].焊接,2012(3):10-13.
[5]符平坡,朱亮,周超,等.钢轨对接超窄间隙焊接的角变形[J].电焊机, 2013, 43(9):41-43.
[6]龚练,朱亮,杨韬君.焊剂带约束电弧超窄间隙焊接方法应用于钢轨的焊接[C]//第二十次全国焊接学术会议论文集.2015.
[7]郑韶先,朱亮,张旭磊,等.焊剂带约束电弧在超窄间隙焊接中的加热特性[J].焊接学报,2008,29(5):60-63.
[8]谢玉伦,朱亮,柴国云,等. X70管线钢超窄间隙焊接工艺试验[J].热加工工艺,2016,45(1):183-185.
[9]柴国云,朱亮,龚练,等.焊剂片链约束电弧超窄间隙根焊缝成形分析[J].热加工工艺,2018,47(5):231-234.
[2]张佐,姜勇,巩建鸣.异种钢焊接接头碳迁移研究现状[J].热加工工艺,2014,43(7):5-9.
[3]龚练,朱亮,杨韬君.坡口宽度对超窄间隙焊接电弧特性的影响[J].兰州理工大学学报,2016,42(4):32-35.
[4]朱亮,王洪涛,符平坡.钢轨对接超窄间隙焊接试验[J].焊接,2012(3):10-13.
[5]符平坡,朱亮,周超,等.钢轨对接超窄间隙焊接的角变形[J].电焊机, 2013, 43(9):41-43.
[6]龚练,朱亮,杨韬君.焊剂带约束电弧超窄间隙焊接方法应用于钢轨的焊接[C]//第二十次全国焊接学术会议论文集.2015.
[7]郑韶先,朱亮,张旭磊,等.焊剂带约束电弧在超窄间隙焊接中的加热特性[J].焊接学报,2008,29(5):60-63.
[8]谢玉伦,朱亮,柴国云,等. X70管线钢超窄间隙焊接工艺试验[J].热加工工艺,2016,45(1):183-185.
[9]柴国云,朱亮,龚练,等.焊剂片链约束电弧超窄间隙根焊缝成形分析[J].热加工工艺,2018,47(5):231-234.