There are two main forms of welding in the processing technology of space frame accessories, one is spray welding; One is spraying. The ultimate purpose of these two technologies is to make the space frame accessories have good impact resistance, wear resistance, corrosion resistance, and mirror-like appearance. Have you ever known the difference between these two techniques? Under what circumstances is the spray welding effect better? Next, let's learn the following specific content together!
Spraying materials are different, spray welding requires the use of self-fluxing alloy powder, and spraying is not high requirements for the self-fluxing of powder, and not necessarily self-fluxing alloy powder, a variety of self-fluxing alloy powder can be used for spray welding and can be used for spraying, but spraying powder does not have self-fluxing can only be used for spraying and not for spray welding process.
In the process of spraying and spraying welding, the preheating temperature before spraying is different, the influence of heat on the workpiece is different, and the organization and performance of the workpiece after spraying are also different.
The coating density is different, the spray welding layer is dense, and there are a few pores in the spray layer.
The ability to bear the load is different, the spray layer can generally withstand a large area of contact, mostly used in the working surface with lubrication conditions, mating surface and other working conditions with small forces, while the spray welding layer can withstand a larger impact force, extrusion stress or contact stress.
Spray welding process should be selected in the following situations:
(1) The surface load of various carbon steel and low-alloy steel is large, especially the impact load, which requires the coating and the matrix to be bonded to the workpiece with the strength of 350-450N /mm2.
(2) Used in corrosive media, requiring dense coating and no porosity.
(3) The original design of the workpiece surface adopts quenching, carburizing, nitriding, hard chromium plating and other processes, requiring a high surface hardness.
(4) The working environment of the workpiece is harsh, such as strong abrasive wear, erosion wear, cavitation and so on.
(5) oxy-acetylene flame alloy powder spray welding process is suitable for surface strengthening or repair of various carbon steel and low alloy steel parts,
Spray welding process cannot be used in the following situations:
(1) Materials lower than the melting point of the alloy, such as aluminum and its alloys, magnesium and its alloys, brass, bronze.
(2) The workpiece is a slender shaft or a very thin plate and does not allow deformation.
(3) The original design of the workpiece is very demanding, and the metallographic organization is not allowed to have any change.
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