Journal of Welding Science

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Ziaei Laleh V, Hamed Zargari H, Mahdavi S, Rashedi H. Microstructural engineering of crack-free and corrosion-resistant weld interfaces in gray cast iron surface repairs using IP-GMAW. JWSTI 2026; 12 (1) :35-51
URL: http://jwsti.iut.ac.ir/article-1-531-en.html

Welding is one of the methods of surface repair of cast irons. In this study, surface repair of gray cast iron was first performed by gas metal arc welding method with ER70S-6 welding wire under inter-pulse current, heat input of 393 J/mm and dilution of 17%. Also, to compare the results, two samples were welded with ENi-CI and E6013 covered electrodes. Microstructural studies showed that the microstructure of the interface of the sample is composed of martensite with fine lathes and upper bainite. Despite the presence of cementite (Fe₃C) next to alpha iron (α-Fe) in the interface area, the formation of incomplete mixing zone with bainite lathes in the ferrite zone has led to increased toughness and prevented crack formation. The hardness of the ER70S-6 sample was similar to that of the E6013 sample at the interface, at about 809 Vickers, which is 334 Vickers higher than the hardness of the ENi-CI sample. The results of the open circuit potential and potentiodynamic polarization tests showed that the ER70-CI sample, with a corrosion potential and current of -653 mV and 6.8 μA/cm², had a higher polarization resistance and was more resistant to galvanic corrosion than the ENi-CI sample (-622 mV and 8.9 μA/cm²).