Cleanliness Enhancement of the Bath Surface within a CGL Snout

Many defects can be attributed to poor quality of the galvanising bath surface within the snout area. As the strip enters the bath any material that is less dense than zinc will float on the bath surface (i.e. dross and zinc oxides) and due to the momentum of the strip can be dragged onto the surface and cause subsequent defects on the finished strip. Corus Research, Development & Technology, Port Talbot, Wales, has been working with their various continuous sheet galvanizing lines with means to lower the afore mentioned defects. The use of pumps within the snout area has been investigated and is reported. Water modelling in a test tank, in conjunction with Metaullics Systems Division, was used to evaluate various pump inlet / outlet designs, the optimum position and flow of the pump outlet/inlet, as well as evaluating the different scenarios of using pumps to pull, push and various combinations of the two. The pumps have then implemented on Corus' ZODIAC galvanising line and have helped to dramatically reduce the volume and severity of snout bath surface related defects.