Join securely – prevent corrosion
Welding stainless steel is a special challenge. To create clean seams and permanently stable connections with minimal risk of corrosion it is important first of all to determine the stainless steel exactly. After this, the welding method and the welding process must be exactly aligned to this. Welding is usually carried out with TIG, MIG, and manual metal arc welding methods.
Each stainless steel is different
Stainless steel is a collective term that comprises in particular alloyed and unalloyed steels. Frequently, only rustproof steels are designated as stainless steels. The alloy proportion of low- and high-alloy stainless steels is stipulated exactly. These are differentiated as austenite rustproof Cr-Ni steels and ferritic/low corrosion chromium steel. To guarantee that the properties are retained even after welding, the welding method and the welding filler matching the material must be chosen exactly and the welding process (gas volume, heat input, cooling phases) must be adapted accordingly.
MIG, MAG, TIG and manual metal arc welding
Stainless steels can usually be easily welding with the MIG/MAG method. High-alloy steels are very suitable for the MIG process. However, particular attention should be paid here to the oxide layers caused by the process. These remain on and next to the seam and must be removed completely to maintain the material’s corrosion resistance. In addition, when high-alloy steels are welded it is essential that all overheating is avoided.
TIG welding of stainless steels is used in particular to weld root run and small diameter pipelines. Austenitic steels are particularly good for TIG welding and lead to good welding results. However, attention must be paid to overheating because of the low welding speed and the material’s low thermal conductivity.