Bridging the joint gap with wire feed laser welding

Laser welding of carbon and stainless steel using wire feed has been investigated using a 3.0 kW CO2 laser system. A straight thin tube nozzle, attached to the laser beam nozzle, was used to deliver the wire to the weld zone. This technique was found to be able to accommodate larger joint gaps than autogenous laser welding. A gap of up to 1.0 mm for 2.0 mm thick butt joint has been welded successfully. This is a significant improvement over autogenous laser welding. Mixing analysis revealed that the wire is uniformly distributed in the weld metal although a larger joint gap tends to accommodate more wire. The practical implication of these results is that tight ft-up requirements for laser welding can be relaxed somewhat for many demanding industrial applications. (C) 1999 Elsevier Science S.A. All rights reserved.