坡口预留间隙对高强度钢厚板打底焊缝成形的影响

Effect of reserved groove gap on backing welding of high-strength steel thick plates

利用MSC.Marc有限元分析软件对低合金高强度钢厚板打底焊热过程进行数值模拟,从温度场角度分析坡口预留间隙大小对焊缝根部熔合的影响,并通过焊接试验对模拟结果进行验证和补充.结果表明,在低合金高强度钢要求的焊接热输入下,当预留间隙小于2 mm时,打底焊缝根部出现未熔合或未焊透缺陷;当预留间隙增大到2-4 mm时,打底焊缝根部熔透,焊缝成形良好;当间隙增大到5 mm以上后,热源不足以熔化较多的侧壁母材金属,可能出现未熔合,实际焊接时需要采用大热输入摆动才能熔合良好.

The finite element simulation of the backing welding of the high strength steel plates was built by using MSC.Marc and the effects of the reserved groove gap on backing weld root fusion was investigated based on the welding temperature field. And the results of simulation were verified and supplemented by the experiments. The results showed that,under the low alloy high strength steel required welding heat input, when groove gap size was less than 2 mm,the backing weld root appears incomplete fusion defects. When the gap increases to 2-4mm,the backing weld has single face welding-double face forming. When the gap increased to more than 5 mm,the heat resource could not reach to the base metal of the groove sidewall and the weld root appeard incomplete fusion,and was necessary to use swing welding with high heat input for good fusion.