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利用光学电子显微镜、扫描电镜和透射电镜,以及硬度测试、拉伸试验等手段,对不同焊接参数下微合金高强钢的组织形貌和力学性能进行了研究。结果表明,在低焊速下,微合金钢的焊接接头出现缺陷,随着焊接速度的增加,焊接接头的宽度减小。焊缝区的组织在低焊速下会出现少量的贝氏体和铁素体,但主要组成为板条马氏体。热影响区的组织呈现不均匀状态,其细晶区组织细小,粗晶区组织晶粒尺寸粗大。微合金高强钢的焊接接头硬度峰值位于粗晶区,接头的拉伸断裂位置出现在母材区。
The microstructure and mechanical properties of microalloyed high strength steel under different welding parameters were studied by means of optical electron microscopy, scanning electron microscopy and transmission electron microscopy, as well as hardness test and tensile test. The results show that the welding joints of microalloyed steels have defects at low welding speeds, and the width of welded joints decreases with the welding speed increasing. Weld zone organization at low welding speeds will appear a small amount of bainite and ferrite, but the main composition of lath martensite. The heat-affected zone shows a non-uniform microstructure with fine grain structure and coarse grain size in the coarse grain zone. Micro-alloy high-strength steel welded joints peak hardness is located in the coarse grain zone, tensile splice joints appear in the base metal area.