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

In the paper, it was studied corrosive wear mechanism of various materials against ceramic in molten-zinc. Through analyzing corrosive wear principle and influencing factor, theory basis was prepared for further research and selected champion materials.Firstly, have designed and made a test apparatus to simulate working condition of dip-roll bushing in hot-dip galvanizing. The apparatus was able to approximately simulate actual working condition, measure friction torque to monitor corrosive wear process.Six kinds of selected material was as follow: 1Cr25Ni20Si2, M2, H13, Co-based superalloy, Fe-based superalloy and borided Cr12, and corrosion rate and hardness have been measured. Borided Cr12 excluded from molten-zinc. Corrosion resistance of Co-based superalloy was the best. Due to too low hardness of 1Cr25Ni20Si2 and worse corrosion resistance of M2, the two materials have been eliminated. And then other four materials were slided against Al₂O₃ and Si₃N₄ in molten-zinc. Corrosive wear rate showed that corrosive wear resistance of Co-based superalloy was best in four kinds of metal, whether againat Al₂O₃ or Si₃N₄.Wear process has been illustrated from friction torque. In curve about change of friction torque with time, normal time of Co-based superalloy was longest in four kinds of metal, whether against Al₂O₃ or Si₃N₄. That still proves elemental corrosive wear resistance of Co-based superalloy.When metal was corroded, zinc was diffused to matrix of materials according to analysis about corrosion mechanism, zinc compound generated and dispersed to molten-zinc during the time. Uniform corrosion happened on homogeneous H13. Corrosion resistance of compound phase is better than solid solution phase, whether in Fe-based superalloy or Co-based superalloy .Wear was more important than corrosion in corrosive wear mechanism of metal.Wear mechanism of four materials was grinding abrasion, plastic deformation, brittle fracture, pull-out.Corrosive wear inactivation of mating materials was resulted from crossing action of several wear mechanism. Ratio of microhardness of corrosion products to that of matrix of metal materials, mechanical performance, morphology of material and so on, were the key factors to wear mechanism.