APPLICATIONS & WELDING
Stainless steels find a large range of applications due to their excellent corrosion and oxidation resistance. They exhibit also, depending on their type, other interesting properties like toughness, heat resistance, wear resistance, etc.
As example, stainless steels are mainly used in the following areas:
- cutlery industry, exhaust systems for automotive made of ferritic grades;
- storage tanks for liquefied natural gas (LNG) made of austenitic grades,
- shafts and valves of martensitic grades
- heat exchangers and pumps for seawater desalination of duplex grades
- aircraft parts of precipitation hardening grades
The weldability of stainless steels is different from one series to another one. Among the inherent problems to the weldability of these materials, we quote:
- overheating and grain coarsening in ferritic and duplex grades,
- 475°C embrittlement in ferritic and duplex grades,
- Cold cracking for martensitic and some precipitation hardening grades ;
- Hot (solidification) cracking in austenitic grades (3xxx and PH series) ;
- Precipitation of brittle intermetallic phases in duplex grades and in the weld metal of austenitic grades containing delta ferrite;
- Sensitization or intergranular corrosion in austenitic grades ;
- Heat tint and oxidation of the root pass and HAZ for the whole stainless steel series.
