Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
There are two main forms of welding in the processing technology of grid accessories, one is spray welding; the other is spray coating. The ultimate goal of these two technologies is to make the grid accessories have good impact resistance, wear resistance, corrosion resistance, and mirror appearance. So do you know the difference between these two technologies?
The spraying materials are different. Spray welding requires the use of self-fluxing alloy powder, while spraying does not require high self-fluxing of powder, and it is not necessarily self-fluxing alloy powder. Various self-fluxing alloy powders can be used for both spray welding and spray coating, but spray powder does not have self-fluxing property and can only be used for spraying but not for spray welding process.
The workpiece is heated differently. In the process of spraying and spray welding, the preheating temperature before spraying is different, the workpiece is affected by heat differently, and the organization and performance of the workpiece after spraying are also different.
The density of the coating is different. The spray welding layer is dense, while there are a few pores in the spray coating.
The ability to bear loads is different. Spray coatings can generally withstand large-area contact and are mostly used on working surfaces with lubrication conditions, mating surfaces and other working conditions with less stress. Spray welding layers can withstand greater impact forces, extrusion stress or contact stress, etc.
Spray welding technology should be used in the following situations:
(1) The surface load of various carbon steel and low-alloy steel workpieces is large, especially the workpieces subject to impact loads, requiring the coating to have a bonding strength of 350-450N/mm2 with the substrate.
(2) When used in corrosive media, the coating is required to be dense and free of pores.
(3) The original design of the workpiece surface uses quenching, carburizing, nitriding, hard chrome plating and other processes, requiring the surface to have a high hardness.
(4) The workpiece works in a harsh environment, such as strong abrasive wear, erosion wear, cavitation, etc.
(5) Oxygen-acetylene flame alloy powder spray welding process is suitable for surface strengthening or repair of various carbon steel and low alloy steel parts.
The following situations cannot use the spray welding process:
(1) Materials below the melting point of the alloy, such as aluminum and its alloys, magnesium and its alloys, brass, and bronze.
(2) The workpiece is a slender shaft or a very thin plate that is not allowed to deform.
(3) The original design requirements of the workpiece are very high, and the metallographic structure is not allowed to change.
(4) Highly hardenable nickel-chromium-molybdenum alloy steel.
