Submersible pump wear protection innovation

In the 1960s and 1970s, China began to apply epoxy resin and its compounds to submersible pumps for anti-abrasion protection. In the 1980s have also developed a composite dragon coating, polyurethane coating imitation ceramic coating and rubber coating and other non-metallic coatings. In addition, there are some non-metallic coatings formed using materials such as quick-acting titanium rubber, rubber, enamel, ceramic, glass and the like, which are less used due to complicated processing techniques and the like. In the 90s of the 20th century, the United States also introduced the United States DEVCON DEV agent, ARC composite coatings, synthetic rubber and other polymer materials. These non-metallic coating materials in pumping station harsh environment, often due to the coating and the metal matrix bonding ability and the material itself is not enough hardness, it is difficult to achieve the desired anti-cavitation, anti-erosion effect. 112 metal coating research [2] In the submersible pump anti-erosion surface protection technology is also widely used metal surface protective layer. The most widely used is electrode surfacing and wire coating. The use of stainless steel electrode surfacing method to ensure that the welding layer and the substrate with a high bonding strength, but the surfacing fade rate, the welding thick and uneven processing margin, the solderability of the work of the substrate material demanding . The surface of the submersible pump blade treated by the surfacing welding method is generally subjected to new cavitation destruction immediately around the surfacing spot until no cavitation damage occurs at the surfacing site until the bottom of the surfacing layer. Wire sprayed stainless steel coating formed by the combination of mechanical particles, not suitable for submersible pump impact load and cavitation repair. For some large submersible pump workpieces, such as large diameter (more than 3 meters in diameter) axial pump impeller chamber, you can inlaid a stainless steel plate on the surface to increase the anti-erosion ability. However, this method requires the workpiece to be sent to a large submersible pump factory specialized processing, turning, setting, welding, expensive, long cycle, non-submersible pump pumping station can be implemented. Alloy powder coating is developed on the basis of wire spraying. Compared with the surfacing method, the molding is smooth, the thickness is easy to control, the fading rate is small, the method is simple, the heat source is easily obtained, and the processing is not limited by the climate and the site. However, since the sprayed layer is formed by regularly stacking alloy powder particles in a semi-molten state sprayed onto the surface of a substrate at a high speed and in a layered structure, the physical properties of the sprayed layer are directional and, in each spraying process, Powder particles appear coagulation, shrinkage, deformation and other phenomena in the coating to develop an internal stress, so the alloy powder coating is generally only used for cavitation and abrasion less serious surface protection of submersible pumps. 12. Surface Protection Materials and Workmanship Requirements 121 Technical Requirements for Surface Protection Materials Anti-wear coatings must have [1]: (1) high strength and hardness to resist cavitation and abrasion damage; (2) Toughness to absorb the impact energy; (3) has a high bond strength to ensure that the coating in the pump 30-35 meters per second under the impact of high-speed flow will not spall; (4) coating materials must be affordable, In order to ensure that large and medium-sized submersible pump stations and a large number of rural small and medium-sized submersible pump stations to promote the use of; (5) coating materials should be non-toxic, non-flammable, explosive materials, easy to custody transport, do not pollute the surrounding environment . 122. Processing Requirements In order to ensure the promotion and application of surface protection technology, the processing technology must be: (1) The process is simple and can be mastered by different operators; (2) The tools (tools) used in the processing should be Easy to get in the market or general pump station maintenance work necessary, and affordable, without special and expensive equipment; (3) the process should not be affected by the season and the surrounding environment, to ensure that the pump station in winter and spring Maintenance period can be carried out; (4) The coating does not require special thermal maintenance, coating quickly solidified or put into use to shorten the same period of maintenance. 2. Progress in alloy powder spray welding Spray protection is a metal surface protection technology developed on the basis of spraying and welding with the successful development of low melting point powder materials. As the spray layer undergoes remelting process, the coating is dense and non-porous, the surface is smooth and flat, with the advantages of material saving, good quality and high efficiency. The surface hardness of the spray coating layer can be up to HRC60-70 and can be extended several times or even ten times Diving, pump over-current components of the service life. 21 Spray-welding Alloy Powder Material Optimization 211 Optimization Tips In order to ensure the quality of spray coating, to prevent the deformation of the workpiece and the generation of coating cracks, coating material research and optimization of the technical route: (1) through the ratio optimization, change the hardened phase Of the particle size, the number of crystal grain size and size, in order to obtain a reasonable organizational structure and distribution status. (2) According to the characteristics of submersible pump cavitation and erosion, adjust the performance of materials in a targeted manner, which not only ensures the excellent abrasion resistance of the material, but also restrain or reduce the generation of cracks and improve the solderability. (3) Determine reasonable technical parameters and process parameters to improve the binding conditions under the conditions of use of the coating.

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