Advantages and application scope of phosphating technology at room temperature for iron and steel

Characteristics of phosphating film: strong adhesion with base metal, firm combination, dense and porous, strong adsorption on coating Therefore, it can be used as the base of common coatings, so that the phosphating layer and the coating layer have strong adhesion and corrosion resistance In the atmospheric environment, after the post-treatment, its corrosion resistance is better than the oxidation blackening protective layer During cold extrusion of general steel, the temperature rise caused by deformation can reach 300 ℃ far below the thermal boundary of the phosphating film, so the phosphating film has good thermal adhesion resistance In the cold extrusion process, under certain temperature, the phosphating film reacts with lubricant (soap solution or emulsifier), some fatty acid soap reacts with zinc phosphate zn3 (PO4) 2 in the phosphating film, forming zinc fatty acid (rcoo) 2 with strong lubricity, thus strengthening the lubrication The phosphating film has no adhesion to the molten metal and can be used to prevent the parts from adhering to the molten metal with low melting point The utility model can be used for local nitriding parts to prevent tin staining, can also be used for avoiding the adhesion between the die-casting parts and the mold, reducing friction, avoiding or reducing the surface scratch or crack, so as to prolong the service life of the mold Phosphating film also has high electrical insulation performance, which can be used as electrical insulation layer of silicon steel sheet After phosphating treatment, the mechanical properties and magnetic properties of the steel remained unchanged Application scope of room temperature phosphating technology: 1 Room temperature phosphating technology can be widely used on the inner surface of pipes, gas cylinders and steel parts with complex shapes, as well as on the surface of parts that are difficult to obtain protective coating by electrochemical method For example, it can be used in automobile industry, gear, radiator, brake tile, joint, pipe cavity, screw, nut, etc Petrochemical industry, pipeline, various valves, pump casings, shaft sleeves, blades, etc 2 Hardware, mold, machinery manufacturing industry, various molds, hardware decorative parts, washing machine casings, flat plates, measuring tools, fan blades, bicycle parts, sewing machine parts, etc 3 Weapon industry, bearing, gun, pump body on board, metal parts on board, etc 4 Aerospace industry, bearing journal, piston, landing parts, seat frame, pillar, etc 5 Coating industry, increase the adhesion of organic coating Advantages of normal temperature phosphating technology: according to different treatment temperature, there are three kinds of Phosphating Technology: high temperature, medium temperature and normal temperature High temperature phosphating is generally carried out at 90 ℃ ~ 98 ℃ When the solution is working at high temperature, the volatilization is large, the composition changes fast, the phosphating film is easy to be mixed with precipitates, the crystal thickness is uneven, and the energy consumption is huge Middle temperature phosphating is usually carried out at 50-70 ℃, the composition of the solution is complex and the energy consumption is large However, when the temperature is 15-45 ℃, it does not need heating, saving energy, low cost and stable solution The cost is about 5-6 yuan per kilogram of concentrate and 0.35 yuan per kilogram of working solution after dilution The solution is stable, the adjustment and maintenance of the working fluid is simple and convenient, and the service life is long The working fluid can be generally processed up to 2000 square meters / ton, with a long cleaning cycle, and can be continuously industrialized in large quantities.