Steam Tempering

Steam tempering creates a thin, dark magnetite layer on the steel surface that adheres well and protects against corrosion. If you want to weld such a part, you must completely grind off the layer in the welding area, otherwise you'll get porosity and lack of fusion. The heat from welding will ruin the tempered structure near the weld, so you need to watch out. If you steam temper after welding, it acts like a tempering treatment and relieves stresses, which is good for toughness. For that, the surface must be clean and free of grease, and let the part cool down slowly.