Outer diameter of sink roll varies from 400mm to 800mm. Currently there are three types of sink roll, including none grove, spiral groove and straight groove. If there are gorrves on sink roll surface, there will be less dregs on it. Lifetime of sink roll would be longer and galvanizing quality of strip could be better. Length of roll face is determined by inner of annealing furnace. Roll thickness is up to strip thickness. It’s produced by centrifugal casting, then machined on both surfaces and annealed.