Fatigue performance of Q355B steel substrate treated by grit blasting with and without subsequent cold spraying with Al and Cu

Abstract Grit blasting and cold spraying are widely used as surface modification processes to improve the performance of steel substrates. In this study, 80-mesh grits were optimized for grit blasting through a bonding quality evaluation of cold-sprayed Al and Cu coatings on Q3555 steel substrate blocks. Fatigue testing was conducted on Q355B steel specimens treated by grit blasting with and without subsequent cold spraying with Al and Cu to study the fatigue behavior of the treated substrates. The results show that grit blasting with and without subsequent cold spraying can increase the crack length and decrease the crack growth rate, thereby prolonging the fatigue life of Q355B steel substrate, and that grit blasting with subsequent cold spraying with Cu achieves a greater improvement effect than cold spraying with Al. Finally, scanning electron microscopy (SEM) was performed on the fatigue fractures to examine the mechanism by which the fatigue life is prolonged by grit blasting and cold spraying.