厚板双TIG打底焊缝根部熔合的数值模拟

建立了厚板双面双TIG打底焊有限元模型,并通过焊接试验验证该模型的合理性及准确性.在此基础上分别对不同错边及钝边的坡口形式下厚板打底焊温度场进行了模拟.结果表明,随着预留间隙的增大,双弧打底焊可熔化的钝边量增大,可允许的错边范围先增大后减小;在厚板打底焊时,当钝边及错边之和不超过4 mm时预留2~4 mm的间隙能够得到根部熔合良好的焊缝;存在的错边及钝边量之和超过6 mm将产生未焊透缺陷;当钝边及错边之和在4~6 mm之间时打底焊缝根部熔合情况随着间隙改变而变化.

Numeral simulation of root fusion in double-sided TIG backing welding of thick plate

A finite element model for double-sided TIG backing welding of thick plate was established, and the reasonableness and accuracy of the model were verified by welding experiments. Then, the temperature fields in backing welding thick plate were simulated for different groove designs with different sizes of misalignment and root face, respectively. The results show that, with the increase of the reserved groove gap, the allowable range of root face increased using double-sided TIG backing welding, and the allowable range of misalignment increased first and then decreased. In backing welding of thick plate, when the sum of root face and misalignment was less than 4 mm, the weld with good root fusion could be obtained with reserved 2-4 mm groove gap. When the sum of root face and misalignment was more than 6 mm, incomplete penetration occurred. When the sum was between 4 mm and 6 mm, the root fusion changed with the reserved groove gap.