Enhancement in the Hardness and Corrosion Resistance of Mild Steel Surfaces by Nickel-Chromium Addition and Rapid Cooling After Welding

Abstract

In a corrosive environment, it is crucial to increase the hardness and corrosion resistance of mild steel bucket excavators. Making a hard layer of nickel-chromium (NiCr) alloy by the deposition method is one of the many approaches to achieve this. In this research, a hard layer was deposited on the upper surface of mild steel using manual metal arc welding (MMAW). Starting with the addition of NiCr alloy during welding, the process continued with a quenching technique using different cooling media. In order to examine elemental composition, crystal structure, and microstructure, Optical Emission Spectroscopy (OES), X-ray diffraction (XRD), and optical microscopy (OM) are employed. The evaluation of hardness values, material deterioration, and electrochemical behaviour of the deposited layer involves hardness tests, digital balances, and potentiostats. Due to its improved hardness and corrosion resistance, NiCr has been successfully added to deposition layers. The increase was attributed to the presence of martensite and ferrite phases generated by the quenching technique and NiCr on the surface layer. The hardness value and corrosion resistance of samples coated with NiCr after being rapidly cooled in an oil medium are found to be suitable for excavator buckets, according to experimental findings.

Keywords

• corrosion resistance
• nicr
• welding
• hardness
• oil
• quenching