What is Preheating?

Preheating is the process applied to raise the temperature of the parent steel before welding. To slow the cooling rate of the weld and the base material, potentially resulting in softer weld metal and heat affected zone microstructures with a greater resistance to fabrication hydrogen cracking.
What is the purpose of Preheating in welding?
The process of preheating involves heating the area around the weld joint or the entire part to a specified temperature before welding. This reduces the cooling rate of the weld and drives out moisture, which in turn helps prevent hydrogen buildup and the potential for cracking.
A crucial step in many welding applications, preheating slows the rate of cooling in a finished weld, lowers the amount of hydrogen in it, and reduces the risk of cracking. Artificially introducing heat into the base metal by means of an external heat source adds a step to the welding process; however, it can save you time and money in the long term by reducing the potential for a failed weld that requires rework. You have numerous methods for preheating the base material. Each has benefits and drawbacks. The best choice for a specific application depends on several factors, including any code requirements that may apply. Best practices that contribute to proper preheating and a high-quality weld.
Why is Preheating in welding important?
Welding preheat is important in many applications. This reduces the cooling rate of the weld and drives out moisture, which in turn helps prevent hydrogen buildup and the potential for cracking. Several methods can be used for welding preheat, including induction, open flame, resistance heating and convection ovens.
Back