The difference between thermal spraying and spray welding

       1. The bonding mechanism of the coating is different

The bonding mechanism of thermal spraying includes mechanical bonding, metallurgical chemical bonding and physical bonding. Among them, mechanical bonding is the main bonding method, and the bonding mechanism of spray welding is chemical metallurgical bonding to achieve permanent bonding between atoms.



2. The heating conditions of the workpiece are different

There is no remelting process in thermal spraying, and the surface temperature of the workpiece can generally be controlled below 250 °C. During spray welding, it does not deform or change the structure of the workpiece to melt the coating. The remelting temperature can reach above 900 °C, which will not only cause deformation of the workpiece, but also And will cause annealing or incomplete annealing of most workpieces



3. The bonding state with the substrate is different

The bonding strength of the thermal spray coating and the surface of the substrate is mainly mechanical occlusion. Although there is micro-metallurgical bonding, the bonding strength of the coating is not high. Generally, it forms a metallurgical bond with the surface of the substrate after melting at 30-50MPa, and the bonding strength can reach 343- 440mpa



4. Different spraying materials

Spray welding requires the use of self-fluxing alloy powders, while thermal spraying does not require high self-fluxing alloy powders, nor is it necessarily self-fluxing alloy powders



5. The structure of the covering layer is different

The spray welding layer is uniform and dense, and is generally considered to have no pores, while the thermal spray coating has pores.



6. Different carrying capacity

The thermal spray coating cannot withstand impact load and high contact stress, so it is suitable for surface spraying of various surface contact parts. The spray welding layer can withstand impact load and high contact stress, and can be used for line contact