Original paper(Vol.49 No.3 pp.310)
Effect of residual stress on strength of as sprayed coatings
Itoh Yoshiyasu; Andoh Hideyasu; Shindoh Takahiko
Abstract:A thermal spraying process is useful to be able to coat on substrates without any thermal damages. Therefore, it is possible to coat the high melting-point material such as steels, on the low melting-point material such as aluminum. However, it is generally inevitable to develop residual stress due to difference in thermal expansion and temperature between coating and substrate. Therefore, the strength of thermal sprayed coatings is affected by the residual stress in the coating layer.
In this study, the strength behavior of thermal sprayed aluminum with carbon steel and 13% chromium stainless steel was made clear by four-point bending test. The results revealed that the strength of 13% chromium stainless steel sprayed, specimen showed high value in comparison with the carbon steel sprayed specimen using X-ray diffraction method. The compressive residual stress could be measured in 13% chromium stainless steel coatings. On the other hand, the tensile residual stress could be measured in carbon steel coatings. It was confirmed that the good agreement could observed between the residual stress characteristics and the bending strength of coated specimen.
Key Words:Coating strength, 13% chromium stailess steel, Carbon steel, Thermal sprayed coating, Aluminum, residual stress, Finite element analysis