焊接熔池中元素分布规律及其影响因素的研究进展

焊接过程中焊接熔池内部的流体流动传热过程对熔池的形状、气体及夹杂物的吸收、聚集和逸出等影响很大,尤其影响元素在熔池中的分布。研究发现,熔池内流体主要受表面张力、浮力和电磁力的作用,其中表面张力对熔池形状起主导作用;焊接热输入、功率、焊接速度均对焊接熔池的形成有不同程度的影响。在焊接过程中,不同材料在交界处会发生元素互扩散,不同的元素扩散系数相差较大,而同种元素在不同扩散深度处的扩散系数却相差不大。由于焊缝中元素分布是否均匀直接关系到焊接接头的质量,因此元素在熔池熔化过程中具体的扩散形式以及在熔池凝固后元素的偏析情况是未来的研究热点。

Influencing Factors of Element Distribution in Welding Pool:A Review

The fluid flow and heat transfer in welding process has a great influence on the shape of welding pool, the absorption and accumulation of gas and inclusions, especially on the distribution of elements in the molten pool. Sufficient researches have showed that the fluid in the molten pool is mainly affected by surface tension, force and electromagnetic force, in which the effect of the surface tension is the key factor on the welding pool shape. The welding heat input and the welding speed also have different effects on the formation of the welding pool. The element interdiffusion phenomenon occurs at the interface between different materials. The diffusion coefficient is obviously distinct for diverse elements at different diffusion depth, but it is similar for the same elements. The uniform distribution of the elements has a significant influence on the quality of the welding joint. In the future, the research will focus on the specific diffusion form and the segregation of elements in the molten pool.