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【Plite Fasteners】U-shaped bolt surface technology. We may not know much about U-shaped bolts. U-shaped bolts are one of the commonly used fasteners, but we know very little about the surface technology of bolts, so next, Prolite Fasteners will explain the surface technology of bolts to everyone. [U-shaped bolt surface treatment process] One of the most effective methods for U-shaped bolts is galvanizing. Galvanizing refers to a surface treatment technology that coats the surface of metal, alloy or other materials with a layer of zinc for aesthetics and rust prevention. The main method used is hot dip galvanizing. Galvanizing has a wide range of applications, such as steel nails, iron nails, fasteners, various hardware fittings, scaffolding fasteners, etc. 1. Several common galvanizing methods for U-shaped bolts. According to the different surface colors and functions after galvanizing, there are eight common galvanizing methods: electroplated white zinc, blue and white zinc, multicolored zinc, black plating, chrome plating, hot dip galvanizing, Dacromet plating, and natural color. 2. What are the common factors that affect galvanizing of U-shaped bolts? The common factors that affect galvanizing mainly include the following.: (1) The pretreatment is not thorough. There is an oxide film on the surface of the workpiece, which affects the normal deposition of zinc. (2) Poor conductivity. The current is consumed in the wire and the current distributed to the surface of the workpiece is too small. (3) The workpiece contains high carbon content. High carbon steel, cast iron, etc. will reduce the hydrogen evolution potential, accelerate hydrogen evolution on the surface of the workpiece, and reduce the current efficiency. (4) The workpieces are tied too densely. During galvanizing, the workpiece is partially shielded, causing the coating to be too thin. (5) The temperature of the plating solution is low. When the temperature of the plating solution is low, the current density distributed decreases accordingly, and the deposition speed of the plating layer also inevitably decreases. (6) The sodium hydroxide content in the plating solution is high. When the sodium hydroxide content is high, the current efficiency decreases accordingly. (7) The additive content in the plating bath is low. Low additive content will affect the dispersion ability and the coating will appear to be too thin in some areas. (8) The area of the plated parts is insufficiently estimated, and the current density delivered during plating appears to be too small. (9) The workpiece hanging method is improper and the distance between the workpiece and the zinc anode is too large. The position should be adjusted. (10) The workpiece is over-corroded. Reducing the hydrogen evolution potential, the hydrogen evolution acceleration current efficiency on the workpiece surface is reduced, thus affecting the zinc deposition rate. An appropriate amount of corrosion inhibitor should be added to the pickling solution. If the local oxide scale is too thick, it should be removed mechanically first. Check more during the pickling process. (11) Anode passivation. The effective area is reduced, affecting the normal distribution of current. (12) The sodium hydroxide content is low. If the sodium hydroxide content is low, the current density cannot be increased and the anode will be passivated.