焊接工艺对高锰钢焊接接头组织和性能的影响

Effect of welding process on microstructure and properties of high manganese steel welded joint

  • 摘要:
    目的 旨在探究不同焊接工艺对高锰钢焊接接头组织和性能的影响,寻找合适的高锰钢焊接工艺。
    方法 利用扫描电子显微镜(Scanning electron microscopy,SEM)、光学显微镜(Optical microscopy,OM)、X射线衍射仪(X-ray diffractomer,XRD)等手段,并通过常温拉伸、常低温冲击以及显微硬度等试验研究了焊条电弧焊(Shield metal arc welding,SMAW)、埋弧焊(Submerged arc welding,SAW)和熔化极气体保护焊(Gas metal arc welding,GMAW) 3种焊接工艺对国产超低温高锰钢焊接接头组织和力学性能的影响。
    结果 结果表明,3种焊接工艺条件下,热影响区组织为奥氏体与少量夹杂物颗粒,熔合线附近晶粒粗大且狭长,焊缝组织为柱状晶;拉伸试验断裂位置均为焊缝,SAW,SMAW,GMAW焊接试样的抗拉强度最大值分别为775.4 MPa,686.7 MPa,749.2 MPa,拉伸性能均能满足工程要求;SAW焊缝−196 ℃冲击吸收能量是80.7 J,GMAW的−196 ℃冲击吸收能量是71.7 J,SMAW的−196 ℃冲击吸收能量为64.0 J,冲击断口均为韧性断裂;3种焊接工艺的焊接接头显微硬度最小值均在焊缝中心,焊缝中心硬度峰值SMAW最小,SAW较大,GMAW最大。
    结论 SAW综合性能最好,GMAW次之,SMAW最差。

     

    Abstract: Objective The aim is to explore the effects of different welding processes on the microstructure and properties of high manganese steel welded joints, and to find suitable welding processes for high manganese steel. Methods The effects of SMAW, SAW and GMAW processes on the microstructure and mechanical properties of domestically produced ultra-low temperature high manganese steel welded joints are studied by using scanning electron microscopy (SEM), optical microscopy (OM), X-ray diffractomer (XRD) and other methods, as well as through experiments such as room temperature tensile testing, low temperature impact testing and microhardness testing. Results The results show that, under the three welding process conditions, the microstructure of the heat affected zone is austenite with a small amount of inclusion particles, the grains near the fusion line are coarse and narrow, the weld microstructure is columnar.The fracture positions in the tensile testing are all welds. The maximum tensile strength of SAW, SMAW and GMAW are 775.4 MPa, 686.7 MPa and 749.2 MPa. The tensile properties meet the engineering requirements. The impact absorbed energy of SAW weld at −196 ℃ is 80.7 J, the impact absorbed energy of GMAW weld at −196 ℃ is 71.7 J, and the impact absorbed energy of SMAW weld at −196 ℃ is 64.0 J. The impact fracture surfaces are all ductile fracture. The minimum microhardness of the welded joints for three welding processes are all located at the center of the weld. The peak hardness of the weld center is the smallest in SMAW, the larger in SAW and the largest in GMAW. Conclusion The comprehensive performance of SAW is the best, followed by GMAW, and SMAW is the worst.

     

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