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The surface of metal parts requires surface treatment, which is not only for corrosion prevention and rust prevention, but also for the aesthetics of the product. There are various forms of metal surface treatment, such as phosphating, electroplating, spraying, embossing, polishing, and wire drawing. The first three belong to the category of coatings, which usually not only ensure the aesthetics of the product, but also protect the metal from corrosion; The latter three only serve as surface treatments on the physical level and do not involve any anti-corrosion effect, so apart from stainless steel, these three surface treatments are rarely seen on other metals.

Phosphating

During phosphating treatment, the metal is immersed in a prepared phosphating solution and undergoes chemical and electrochemical reactions to form a phosphate chemical conversion film, also known as a phosphating film, on the surface of the metal. The purpose of phosphating is to protect metals from corrosion, and the surface of the metal after phosphating treatment can enhance the adhesion of the paint during painting, better playing a role in corrosion prevention; In addition, phosphating treatment can also play a role in reducing friction and lubrication in metal cold working processes, and its friction coefficient is the most stable among all coatings, making it very suitable for areas with high installation torque requirements.

electroplate

Electroplating is the process of using the principle of electrolysis to deposit a layer of other metals on the surface of a workpiece as a coating, thereby improving conductivity, wear resistance, reflectivity, and corrosion resistance. In addition to iron-based cast iron, steel, stainless steel, and other non-ferrous metals, the substrate for electroplating can also be non-metallic materials such as ABS plastic, polypropylene, polysulfone, and phenolic plastics. However, special activation and sensitization treatments are required before electroplating non-metallic materials. The corresponding effects of different coatings are also different. For example, gold plating is to enhance the conductivity of the workpiece and enhance signal transmission ability; The function of copper plating is to provide a base, enhance the adhesion ability of the electroplating layer, and prevent rusting. The only drawback of electroplating is that its coating thickness is uneven. The coating at sharp edges is relatively thick, mainly due to the tip effect. Therefore, caution should be exercised when using products that require consistent film thickness.

spray

This surface treatment uses a spray gun or other tool, through the action of a centrifuge or gravity, to divide the coating into uniform and small droplets, which are sprayed onto the metal surface. The metal after spraying treatment can achieve conductivity, wear resistance, insulation, sealing, lubrication, acid and alkali corrosion resistance, as well as other special mechanical and chemical properties. The most basic spraying methods in processing are air spraying, airless spraying, and electrostatic spraying, but there are other derived methods to choose from based on these three methods. The surface adhesion of sprayed products is relatively poor, so attention should be paid to areas with adhesion requirements, such as gaskets, which have a rotating effect during installation and may scrape off the surface coating.

Embossing

Embossing is a technique that uses uneven molds to create patterns on metal surfaces, achieving a relief like effect. According to the embossing method, it can be divided into flat embossing and roller embossing.

polishing

Polishing is the process of reducing surface roughness through physical or chemical methods to obtain a smooth or mirror surface. Its purpose is to better showcase the material and luster of the metal itself, but it cannot improve the accuracy of the workpiece. The processing methods can be divided into ultrasonic polishing, electrolytic polishing, chemical polishing, mechanical polishing, fluid polishing, and magnetic grinding polishing. It should be noted that different methods result in different surface roughness. When selecting a processing method, information such as cost, time, workpiece size, and required surface roughness can be considered.

wire drawing

The surface treatment process of metal wire drawing involves grinding the metal surface to form lines, giving the metal surface a non mirror metallic luster, similar to satin, with a very high decorative effect. Wire drawing lines can be divided into two categories based on the different surface effects: straight lines and messy lines. For straight line drawing, it can also be subdivided into continuous lines and intermittent lines.

The processing methods for wire drawing include flat pressing sand belt drawing (small area), non woven roller brush drawing (large area), wide sand belt drawing (flat), and centerless grinding drawing (cylindrical).