Stainless steel surface polishing

    Polishing is used for pretreatment of stainless steel. The purpose is to reduce the value of surface roughness (Ra) <0.4μm, so that the surface can obtain a bright and smooth appearance, and prepare for subsequent chemical polishing or electrochemical polishing.

    (1) Polishing principle. The theory of leveling believes that when the polishing wheel rotates at high speed, the surface of the stainless steel rubs against the polishing wheel under the action of force to generate a local high temperature, which increases the plasticity of the metal. The convex part of the microscopic unevenness flows to the concave part at high temperature. Filling occurs, so that the surface of the slight unevenness is improved.

    2) Polishing wheel. Laminated by soft cloth pieces, such as cotton cloth and non-woven cloth, without stitching, the polishing paste is applied under high-speed rotation, and the surface is pressed against the polishing wheel to obtain a bright surface.

    (3) The peripheral speed of the polishing wheel, the peripheral speed used for polishing stainless steel is 30~35m/s. When a polishing wheel with a diameter of D=300mm is used, and its rotation speed is 2000r/min, its peripheral speed=31.4m/s. Use a polishing wheel with a diameter of D=250mm, and its speed is 2400r/min.

    (4) Polishing paste. There are white, yellow, green, red and other polishing paste varieties. Because of the high hardness of stainless steel, green polishing paste is suitable. Green polishing paste contains chromium oxide green abrasive and stearic acid and other binders. During polishing, the heat generated by the friction between the stainless steel surface and the polishing wheel melts the adhesive, so that the chromium oxide has a grinding effect and produces a mirror effect.

(Huiputech)