Residual melt

Physical-Chemical Mechanism of Action

The residual melt forms when the metal is not fully solidified during cooling. It still contains un-solidified alloying elements and can lead to segregation.

Metallurgical Relevance & Risks in Welding

A residual melt that lasts too long can lead to hot cracking and zinc buildup, since the material does not become sufficiently solid. This increases susceptibility to corrosion and reduces the mechanical properties of the weld.

Workshop Practice & Instructions

To ensure a short residual melt, it is important to provide fast cooling after welding. This can be achieved by using cooling water or special coolants. The maximum time for the residual melt should be kept under 10 seconds.