焊接电流对X80钢低温焊接接头组织与性能的影响

Effects of Welding Current on Microstructure and Properties of Low-temperature Welded Joints of X80 Steel

通过显微组织分析、硬度测试、拉伸试验、冲击试验、腐蚀试验，利用扫描电子显微镜（SEM）、能谱仪（EDS）和X射线衍射（XRD）等实验手段，研究了焊条电弧焊（SMAW）不同焊接电流对X80钢低温焊接接头组织与性能的影响。结果表明：随着焊接电流增加，热影响区（HAZ）晶粒粗化，并且软化现象更加明显；焊接电流在180～190A的接头综合力学性能最佳，但当电流增加到190-200A时，接头的综合力学性能显著降低；各组接头腐蚀速率相差不大，范围在0．14～0.19g／（m^2·h），腐蚀膜具有较好的致密性，能够阻止腐蚀介质对基体继续进行腐蚀，从而达到较好的耐腐蚀效果。

Influence of different shielded metal are welding （SMAW） current of X80 steel joints under low tern- perature on microstructure and properties were investigated by means of microstructure analysis, hardness test, tensile test, impact test, corrosion test, scanning electron microscopy （SEM）, energy dispersive spectrometry （EDS） and X- ray diffraction （XRD）. The results showed that,with the increase of welding current, grain coarsening in the heat affected zone and softening were more pronounced. The comprehensive mechanical properties of joints were the best under 180-190 A welding current. But when the welding current increased to 190-200 A, the mechanical properties of joints were significantly decreased. The corrosion rate of each joints varied in the range of 0. 14-0. 19 g/（m^2·h）. Corrosion films have good compactness, can protect the corrode substrate from corrosion, which have better corrosion resistance effect.