Interfacial behaviour and stress transfer mechanism of additively manufactured laser cladding sheet-covered steel plates

Abstract

Laser cladding (LC), a metal additive manufacturing process, is employed to strengthen steel plate which has benefits over traditional steel structure retrofit approaches. In this study, the interfacial behaviour between the substrate and LC sheet of laser cladding sheet (LCS)-covered steel plates is investigated, through a series of mechanical tensile coupon tests by considering the effects of the scanning pattern and the thickness and length of the LC sheet. Double-shear pull tests, metallographic tests and microindentation hardness tests are also carried out to reveal the microstructure of the interfacial zone. It is observed from the macro and micro experimental results that the stresses in the LCS-covered plates in tension can be transferred effectively through the interface between the substrate and LC sheet, and perfect interfacial bonding behaviour with no slip could be assumed. A series of finite element (FE) analyses are further undertaken to calibrate such an assumption. Based on the fully bonded interface assumption, for convenient engineering application, a theoretical model is developed to describe the elastic stress/strain distributions of LCS-covered steel plates subject to tension, by following the equilibrium considerations and plane strain elastic theory. The theoretical model is validated by comparing its predictions with the experimental and FE analysis results. The proposed theoretical model would provide baseline solution for future elastic strain/stress analysis of the LCS-covered steel plates.