| Summary: | 碩士 === 長庚大學 === 機械工程研究所 === 89 === High-carbon tool steel is widely used as the material of cutting-tool, plastic-forming mold, and high strength mechanical parts because the steel can be easily heat-treated to obtain high strength and good wear resistance. In this study, electrochemical polishing and chemical polishing of high-carbon tool steel were conducted with rotating disc electrode (RDE) under different operating parameters. Electrochemical deburring of the edge of the thin plate steel after mechanical punching was also performed and evaluated under the polishing process.
To find a suitable polishing electrolyte, anodic polarization measurement was first conducted in various possible electrolytes and then an anhydrous electrolyte consisted of perchloric acid mixed with alcohol was proposed, in which a limiting current plateau was examined in the anodic polarization. Optimal polishing condition could be achieved when the steel was potentialstatically polished in 8V at -15℃ and the surface roughness (Ra) was 0.026mm. The chemical polishing of the steel was conducted in phosphoric-sulfuric-H2O2 mixed acid in 30℃. With an increasing of H2O2 addition, the overpotential was obviously raised. However, less brightening and leveling effect of chemical polishing was examined than that of electrochemical polishing.
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