Temper coloration is produced when welding without oxidation protection (forming). At these points, the passive layer of the stainless steel has been damaged by the welding process, which can lead to corrosion. The use of forming gases is therefore necessary, especially on the inside of the pipe or on the underside of the root, where the shielding gas from the welding torch cannot create a sufficient gas shroud. This is the best possible way to avoid temper discoloration and oxidation.

Forming is an cost-effective, environmentally friendly, and clean process that prevents temper coloration. In the first step, the air inside the pipe is displaced by shielding gas, also called forming gas. At the same time, the forming gas introduced protects the underside of the weld seam (weld seam root). Argon, argon/hydrogen mixtures, nitrogen, or nitrogen/hydrogen mixtures are used as shielding or forming gases. If forming is carried out correctly, the corrosion resistance of the stainless steel is guaranteed.