TWI Industrial Member Report Summary 573/1996
G I Rees
Laser welding is finding increasing application in industry, and the possibility of using lasers to join plates up to 15mm thick is currently being investigated.
In a TWI-led European project investigating the applicability of lasers for welding plates in shipbuilding, many steels were found to be prone to solidification cracking under certain welding conditions. The individual compositional factors usually associated with solidification cracking in other welding processes ( eg S, P & C) were found to correlate poorly with the observed cracking behaviour of these steels. Further trials using the so-called 'wedge test'to investigate the cracking susceptibility of the steels gave a very poor correlation between the results of this test and those from the butt welding studies. This situation revealed that, not only were the fundamental reasons for cracking not understood in these steels, but a test was required which more accurately represented their behaviour in butt welding practice, and was able to rank the steels according to their inherent risk of cracking. This work assesses the suitability of a test for solidification cracking in which a specimen is pre-strained before welding.
- To identify a test which would provide consistent and reliable data on the risk of solidification cracking in laser welds.