Laser lap welding of 80Y90T steel with plasma arc augmentation

An experiment is carried out on 80Y 90T steel, a high strength low alloy steel, that is used in lightweight autobody components. Using a CO₂ laser, it is shown that Plasma Assisted Laser Welding (PALW) can provide increased fusion zone width, when compared to conventional CO₂ welding, even in the presence of poor part fit-up. The negative effects of material gap, on PALW and laser only welds, are explained and the methods are compared. The use of plasma arc augmentation to increase the tolerance to gap of a laser welding system is shown. The influence of the plasma torch on the laser welding process is also examined. It is then shown that the plasma arc is able to reduce the effective reflectivity of the metal, when laser welding. Welded samples are sectioned, analyzed and compared according to the dimensions currently used in industry, for laser welds.