How can improper filler material selection affect welds?

Improper filler material selection significantly affects weld quality and performance. When a filler material is not compatible with the base metals being welded, it can create mismatches in mechanical properties, such as strength, ductility, and brittleness. For instance, using a filler that is too brittle can lead to cracks in the weld or heat-affected zone, compromising the integrity of the joint. Additionally, if the filler does not have similar thermal expansion characteristics, it could introduce stresses during cooling, leading to distortion or failure.

This issue highlights the importance of understanding the mechanical requirements of the welded assembly, including factors like load-bearing capacity and environmental resistance. By choosing the appropriate filler material that matches or complements the base materials, welders can ensure strong, reliable joints that perform well under the intended service conditions.