Effect of multiple repair welding on mechanical performance and corrosion resistance of quenched and tempered 30CrMnSiA steel

Abstract

Present study presents the results of multiple weld repairs made in the same area to evaluate and analyze its effects on the microstructural and mechanical performance of quench and tempered 30CrMnSiA steel. The welding was performed by Tungsten Inert Gas (TIG) welding using H18CrMoA filler rod and five repairs were carried out. Specimens of different repair work were then characterized to find out the variations in microstructure, mechanical properties and corrosion behaviour. Mechanical performance was evaluated by tensile testing, Charpy impact testing, bend testing and hardness testing. Microstructural features were analyzed with optical microscopy. Compositional analysis using spark emission spectroscopy and energy dispersive spectroscopy (EDS) of the samples were conducted and correlated with the mechanical and microstructural findings to substantiate the test results. By increasing number of weld repairs, an overall drop in tensile strength along with slight increase in percent elongation was observed. An increase in impact strength was also observed with increasing number of repairs with a varying rate. Variation in chemical composition and microstructures was also observed with repairs. Corrosion resistance of the samples was decreased with the increased repairs.