Research On Corrosive Wear Mechenism Of Dip-Roll Sleeve In Hot-Dip Galvanizing

It was studied corrosive wear mechanism of serial Co-based (Co-Mo-Cr-Si) alloys against ceramic in molten zinc in the paper.Through analyzing major corrosive wear principle,theory basis was prepared for further study and champion materials'selection.Fristly six kinds of Co-based alloys were designed and done some experiments to measure their corrosion resistance and mechanical property.Corrosion resistance and hardness of T2 alloy were the best,while the bend strength of T1 alloy was better than others.Finally T1 and T2 alloy were selected to slide against Si3N4 and Al2O3 in molten zinc and on the air under the same test condition. Wear tests had been done in a test apparatus,which is done by ourselves and can illustrate wear process by measuring friction torque.The conclusion was drawn by the curve about change of friction torque with time and corrosive wear rate.The corrosive wear resistance of T1 alloy is better than that of T2 alloy when sliding against Al2O3 in molten zinc,while the result is reverse when against Si3N4.According to analysis the corrosion mechanism of T1 and T2 in molten zinc,we found that the corrosion resistance of Laves phase is better than that of Co-rich solid solution.Also we can see that zinc was diffused to matrix of materials and zinc compound generated and dispered to molten zinc during the time.Wear mechanism was grinding,brittle fracture and pull-out.Inactivation of mating materials was resulted from interactive action of sevseal wear mechanism.Ratio of microhardness of abrasive materials to that of matrix of materials,mechanical performance,microstructure of materials and so on,were the key factors to the wear mechanism. Comparing wear test on the air and in molten zinc,we know molten zinc plays a role of lubrication and rejection adhesive wear besides corrosion to Co-based alloys.Corrosive wear have the property of contemporaneity,alternation and synergism.