Tool Steel Weldability

Cemented carbide is simply not weldable by conventional methods, it is composed of ceramic particles held together with a metal binder. It is extremly brittle and its capable of withstanding thermal shock of the type that occur in welding procceses.
Cooling from the welding temperature is the same as a quench from a hardening temperature. Some material are very prone to cracking with drastic quenches. Mass effect cooling can produce the equivalent of a liquid quench. The brittle structure that result from the rapid quench is strained by the shrinkage stresses from the weld solidification and this produces a combination of effect that tend to crack tool steel when they are welded.