Evaluation of mechanical and tribological behavior of galvanized, galvalume and polyurethane-coated steel sheets

Abstract

The current study is performed on three coated steel sheets to evaluate their mechanical and tribological properties. The optical micrograph reveals the dark pearlite structure in the ferrite matrix, whereas the grain size analysis reveals the 4.07 μm mean grain size of the ferrite. The scratch hardness test reveals better scratch-resistant properties for all three experimental samples. The Nanoscratch test reveals a decrease in friction with increasing load from 50 mN to 150 mN for the colour-coated samples. The tensile study shows higher YS and UTS values (410 MPa and 450 MPa, respectively) for the galvalume sample, followed by galvanized and colour-coated steel. In contrast, a higher ductility (~33%) is observed for the colour-coated sample, followed by galvanized and galvalume samples. It is evident and appropriate from the dry heat resistance test that all three steel sheets, viz. galvalume, galvanised and colour coated sheet, can withstand 120C of heat for 24 h. So, all the samples show improved heat resistance properties. Taber abrasion resistance test results reveal that the colour-coated sample shows improved abrasion resistance due to the polyurethane coating followed by galvalume and galvanized steel samples.