Aineenesihitsaus

Aineenesihitsaus, also known as preheating, is a crucial process in welding that involves heating the base metal to a specific temperature before welding begins. This preheating is typically carried out in the vicinity of the joint to be welded. The primary purpose of aineenesihitsaus is to reduce the rate of cooling in the weld zone and the heat-affected zone. By slowing down the cooling process, it helps to prevent the formation of brittle microstructures, such as martensite, which can lead to cracking. This is particularly important when welding high-strength steels, thick sections, or materials that are susceptible to hydrogen-induced cracking.

The required preheating temperature depends on several factors, including the type of material being welded, the thickness of the material, the welding process being used, and the presence of contaminants. Higher preheat temperatures are generally needed for thicker materials and for steels with higher carbon content. The heat can be applied using various methods, such as oxy-fuel torches, induction heating, or resistance heating. Proper monitoring of the preheating temperature is essential to ensure it is maintained within the desired range throughout the welding operation. After welding is complete, a post-weld heat treatment may also be applied to further refine the microstructure and relieve residual stresses.