Laser melting deposition of duplex stainless-steel coating on high strength low alloy pipeline steels for improving wear and corrosion resistance

Abstract

In this paper, a duplex stainless steels coating was successfully prepared on high strength low alloy (HSLA) pipeline steels by laser melting deposition. The microstructure and phase identification of the obtained coating were identified by scanning electron microscope (SEM) and X-ray diffraction (XRD). The tribological behavior and corrosion behavior were investigated by high-speed reciprocating friction and wear tester, polarization test, Eocp–t curves and electrochemical impedance spectroscopy (EIS). Results show that the obtained coating is bonded metallurgically with the substrate and comprises α, γ, M2B and (Fe, Cr)23C6 phase. In addition, the obtained coating shows nearly 22.5% improvement in wear resistance over the substrate and much better corrosion resistance due to its nobler open circuit potential (Eocp), corrosion current density (i corr) and bigger impedance value than the substrate, confirming that the laser melting deposited duplex stainless steels coating can be a promising candidate for the protective coating of HSLA pipeline steels.