Assessment of Hot Crack Properties of Laser Welded Stainless Steel

Crack testing concerning small and fast solidifying laser welds in austenitic stainless steel has been studied. A set of methods has been applied to investigate alloy properties, including (1) Application of known information to predict solidification phases, (2) Weld metal solidification rate measurements for prediction of phases, (3) Various crack tests to assess the crack susceptibility of alloys and (4) A combination of the above for selection of suitable, weldable alloys.

The possibility of using such specific methods for alloys and applications has been investigated and recommendations are given. Results from the solidification rate measurements had high variations. They do not show an expected correlation between the crack resistance and the solidification rate. The employment of pulsed seam welds is assessed not to be usable in the present measurement method.

From evaluation of several crack tests, the Weeter spot weld test has been chosen to form a basis for the development of a practicable method to select specific alloys for welding applications. A new test, the Groove weld test was developed, which has reduced the time consumption and lightened the analysis effort considerably.

The Groove test showed results in good compliance with the Weeter test.