Effect of chromium content on Fe(18-x)CrxB2(X=3,4,5) hardfacing electrode on microstructure, abrasion and corrosion behavior

Abstract

In this study, covered electrodes with Fe(18-x)CrxB2 (x=3,4,5) composition have been produced and coating was carried out on AISI 1010 steel by using electric arc welding method. It was observed that the presence of eutectic boride phases formed as in-situ in the final microstructures. In addition, in the compositions showing hypo-eutectic phase distribution, mainly consist of alpha(Fe-Cr), tetragonal (Fe, Cr)(2)B, orthorhombic (Fe, Cr)(2)B and trace amount of (Fe, Cr)(3)(C,B) phases were determined. In the reciprocal wear test against alumina ball, it was determined that the friction coefficient values of the coating layers decreases with increasing load and changed between 0.844-0.65. However, it has been observed that the change of friction coefficient moves independently of the chromium ratio. It was observed that the wear rate decreased with increasing chromium ratio, despite that increased with increasing load. The lowest wear rate was found 2.32x10(-5) (mm(3)/m) in 3N load for the electrode with the Fe13Cr5B2 composition and the highest value was found to be 8.16x10(-5) (mm(3)/m) for electrode with Fe15Cr3B2 composition at 9N load. Potentiodynamic polarization test has been performed to the surface alloyed layers coated with electrodes with Fe(18-x)CrxB2 (x=3,4,5) composition. According to the potentiodynamic polarization test, it was observed that the corrosion resistance increases with increasing chromium content. According to corrosion test, the I-cor value decreased according to the increasing amount of chromium and was measured as 2.166 and 1.615 and 1.242 mu A/cm(2), respectively. It was determined that the E-cor value increased with increasing chrome ratio and reached -473.991, -450.056 and -347.157 mV respectively.