![[ Visit Client Website ]](images/banner.gif)
Gas metal arc welding (GMAW) of zinc coated steel is a difficult process to accomplish. The vapor produced from the boiling of the zinc causes porosity, spatter, and pore surface quality which is magnified when trying to accomplish the welding at high speeds (> 0.7 m/min (20 ipm)). Lasers, which are used to make butt joints in zinc coated steels also suffers from similar issues as arc welding does in lap joint welding especially if there is no egress for the zinc vapors. The potential of using a combination of laser and GMAW in a hybrid process has not proven to have any synergistic effect and suffers from an unstable weld puddle and poor weld quality.
An alternative to these three approaches is to use a laser with hot wire feed. While the combination of lasers and hot wire is not new, recent breakthroughs in specialized power sources in combination with modern high powered fiber delivered lasers have made possible a new process referred to as High Productivity Laser Hot Wire (HPLHW) . Initial tests show this process can be used to make lap welds on hot dipped 1.6 mm plate at speeds in excess of 2 m/min (80 ipm) travel speed with a very good bead shape , no porosity, acceptable mechanical properties, and no spatter. Additionally the heat input was minimal with little to no coating removed from the back side of the weld.
This paper describes the initial tests along with basic DOE used to gain an understanding of the basic process parameters and how they relate to each other. Outputs from the experiment examine spatter levels, porosity, weld bead shape and strength. The paper will conclude with a projection of advantages of the process on targeted applications.