Metallurgical characterization and corrosion behavior of laser-cladded 310 s + WC alloy coating

Abstract

Metal parts in alkali recovery boilers such as water-cooled wall tubes and primary air nozzles are easily damaged by high temperature alkali corrosion. In this investigation, 310 s steel base alloy powders mixed with WC was applied on the surface of 1020 steel by laser cladding technology to improve surface quality and extend service life. The content of WC in the alloy powder has a pronounced influence on the microstructure and properties of the obtained cladding layer and it was considered as a variable. The microstructures and elements of the cladding layer was investigated by OM, SEM and XRD. In addition, hardness, friction properties, thermal diffusion properties and alkali corrosion resistance of the cladding layer were further investigated. Finally, research results showed that the microstructure of the laser cladding layer has an organization gradient which is subdivided into planar crystal, cellular crystal, columnar crystal and dendrites orderly from the weld junction. The 310 s + 10%WC cladding layer has the highest hardness of 880 HV, and also has the best friction characteristics, wear resistance, thermal diffusion properties and alkali corrosion resistance.