Recent developments in weldability testing

The term "weldability" can be used to describe a wide variety of material characteristics when a material is subjected to welding. These may include the physical and mechanical properties of the material, the ease with which welding can be accomplished from a practitioner's standpoint, or the ability of the material to avoid metallurgical degradation, usually assessed by its susceptibility to cracking during welding or subsequent heat treatment. A number of weldability tests have been developed over the years to evaluate and quantify material weldability. Many of these test techniques have focused on the phenomenon known as "hot cracking". This paper will review the basic concepts associated with hot cracking and other forms of elevated temperature cracking associated with welds and describe some recent advances in the use of testing approaches to quantify susceptibility to these forms of cracking. This description will include the use of the Varestraint test, the cast pin tear test, and the Gleeble(1) thermo-mechanical simulator for quantifying cracking susceptibility and providing comparative measures of weldability among alloys.