TWI Industrial Member Report Summary 755/2002
S M I Birch and R J Pargeter
High Power CO 2 laser welding of structural and shipbuilding steels has been a competitive process for many applications for many years. Solidification cracking remains an unpredictable, and hence difficult to control, problem, however. Effects of chemical composition on the susceptibility of steels to solidification cracking during welding using a 10kW laser have indicated an effect of carbon, which could be maximised at ~0.09%. It is also known that process parameters which affect solidification pattern and weld bead shape can affect the risk of cracking. The present work aimed to explore the effects of chemical composition, including carbon levels of below 0.09%, using a higher powered laser, and to explore variations in focus position and material strength.
- Investigate the effects of steel composition on solidification cracking susceptibility of laser welds made in C-Mn steels, including those with carbon contents less than 0.09%.
- Determine the effect of steel strength on the solidification crack susceptibility of C-Mn steels welded using laser technology.
- Determine the effects of altering the laser focus position on the solidification crack susceptibility of C-Mn steels welded using laser technology.