Welded mechanical parts - Thermal and mechanical treatments

Although fusion welding is currently a high-performance joining technique for metals and alloys used in mechanical engineering, the fact remains that it gives rise to local geometric, structural (metallurgical constituents) and physical (internal elastic equilibrium) modifications, such that in the "as-welded" state, certain welded assemblies cannot fully benefit from the high mechanical and chemical performance conferred on the base material at the end of its manufacturing process. As a result, it becomes necessary either to use special deposition procedures during welding to minimize the impact of thermal cycles, or to subject the structure at the end of manufacture to various thermal or mechanical treatments or finishing operations to restore all or part of the mechanical characteristics affected by the welding operation.

After an essential reminder of the changes that can potentially be observed in the mechanical characteristics of the structure, geometry and internal equilibrium of welded joints, the article describes the effects of the various thermal, mechanical and local finishing treatments used to improve the performance of welded structures with regard to the various failure mechanisms they may encounter throughout their service life.

At the end of the article, readers will find a glossary and table of acronyms and symbols.