水蒸气保护电弧焊焊缝的氢质量分数

HYDROGEN ABSORPTION DURING WATER VAPOR SHIELDED METAL-ARC WELDING

水蒸气保护焊主要用于工件的堆焊修复,成本低是其显著的优点,且焊缝不出现气孔,而其焊缝的氢质量分数受到关注。首先测定了水蒸气保护电弧含焊缝的扩散氢质量分数。分析了电弧区水蒸气分解及解离的热效应,利用数值方法计算出电弧非导电区的温度及氢分压分布;对水蒸气保护下电弧焊熔池中氢的吸入机理进行了探讨。解释了水蒸气保护焊焊缝的氢质量分数不高,不出现气孔的原因。

A water vapor shielded metal-arc welding is mainly used for repairing process. Low cost is prominently its advantage, moreover the welds made with water vapor as shielding gas were significantly more of free porosity, so investigations of hydrogen content in weld metal with this process is stimulated. In the present work the diffusible hydrogen content in steel welds made with this process is determined. The dissociation of the water vapor in arc and energy absorbed by dissociating reaction are analyzed. The temperature distribution of arc and partial pressure of hydrogen are estimated by the numerical method. The hydrogen absorption mechanism during water vapor shielded arc welding process is approached. The reason for not high hydrogen content and free porosity in welds with this process is explained.