Mechanical behavior of structural steel clad by wire arc thermal spraying

Abstract

Thermal spraying is a surface modification technique in which molten particles are deposited to form protective or functional coatings. This study investigated the mechanical behavior of structural steel components strengthened by wire arc thermal spray cladding. The thermal spraying process was performed using martensitic stainless steel wire to achieve a target cladding thickness of approximately 5 mm. Tensile, compression, and bending tests were conducted to evaluate the mechanical performance of the cladding under various loading conditions. The cladding exhibited a Young's modulus of 70 GPa, approximately one-third that of bulk steel. The tensile strength of the cladding was estimated at 231 MPa, with brittle fracture occurring at a strain of 0.3 %. Despite its limited tensile ductility, the cladding contributed to an increase in axial stiffness in the elastic range. In contrast, under compression, the cladding exhibited ductile nonlinear behavior and failed by vertical cracking. The 0.2 % proof stress of the cladding in compression was 1.3 times that of the substrate, indicating adequate load-bearing capacity under compressive stress. In bending tests, the maximum load of clad steel plates was five times that of unclad steel plates, although cracking and debonding of the cladding were observed. These findings suggest that cladding applied by thermal spraying has mechanical characteristics suitable for structural applications, particularly under compressive stress.