Welding Preheat

Advanced automated systems control and document welding preheat to reduce thermal stress in three primary ways. First, it drives off moisture that would release hydrogen that could penetrate the steel and cause porosity and subsequent cracking.

Second, it reduces heat loss to the surrounding metal, minimizing the rate of weld hardening and allowing hydrogen that is present to escape. And finally, it improves the microstructure and durability of the heat-affected
zone.