单电弧TIG焊咬边影响机理的数值模拟研究

避免咬边是提高焊接速度的关键问题.通过对TIG焊温度场进行数值模拟,找到TIG焊在不同焊接速度时熔池成形规律.研究表明:焊接熔池中熔宽最大的位置滞后于熔深最大的位置,影响咬边产生的关键在于动态深宽比.在对模型校核的基础上,从动态深宽比的角度分析了TIG高速焊接时的咬边问题,指出在焊接电流相同的条件下,随着焊接速度的提高,熔深和熔宽都将减小,但熔深减小更多,所以动态深宽比减小,熔池表面张力向内的合力增大,容易产生咬边.即使在保证熔深相同的前提下,随焊接速度的提高,熔池的动态深宽比也会越来越小,导致咬边倾向增加.

Research on numerical simulation of mechanism of the undercut in single arc TIG welding

Avoiding the undercut is the key factor to raise the welding speed. Numerical simulations on the temperature field of TIG welding were carried out, and the formations of weld pool under different welding speeds in TIG welding were found, and on the base of valid model, the undercut under high speed conditions in TIG welding was analyzed. It is found that under the precondition of the same depth of penetration, with the increasing of welding speed, the ration between dynamic depth of penetration and maximum weld pool width decreases, and the undercut appears when it reduced to a critical value.