The influence of chromium content on wear and corrosion behavior of surface alloyed steel with Fe(16−x)Crx(B,C)4 electrode

Abstract

In this study, the electrodes containing Fe(16−X)CrX(B,C)4 (X = 3,4,5) were used for surface alloying on an AISI 1010 steel substrate. The alloy structure of the coating exhibits in-situ composite structure with a large amount of reinforcing carbides and borides phases as to be hypoeutectic and hypereutectic structure in the surface alloyed layer. The obtained composition of the alloy shows that it contains much more interstitial hard phases in the alloyed layer than the conventional hardfacing alloys used in the industrial applications for the hardfacing of the steels. The morphological and microstructural properties showed that layer microstructure changed from hypoeutectic to hypereutectic structure with an increase in chromium content. The results of these studies revealed that the microstructure of hardfacing layers consists of interstitial phases of α(Fe-Cr) and (Fe,Cr)23(C,B)6 as major phases, (Fe,Cr)2(C,B) and (Fe,Cr)7(C,B)3 as minor phases in the in-situ composite structure. The composite hardness’ in the alloyed surface layers of the Fe(16−X)CrX(B,C)4 alloys ranged from 711 HV to 1164.3 HV. Wear test against alumina ball shows that the friction coefficients of the surface alloyed layers decreased with increase in applied loads and decrease in chromium content in the Fe(16−X)CrX(B,C)4 alloy composition. Coefficient of friction ranged from 0.55 to 0.79 in the present study. Wear rates of the surface alloyed steels caused to increase with decrease in chromium content and increase in applied loads. The wear rates of the alloyed layer changed between 3.07 × 10 and 5 mm3/m and 6.95 × 10−5 mm3/m. The corrosion resistance of the alloyed layers was measured by a potentiostatic polarization test. Icorr and Ecorr of the coated layers changed from 1.813 to 9.965 µA/cm2 and −704.786 to −745.792 mV, depending on alloyed layer compositions. With increasing chromium content, the corrosion resistance of the coating layer has changed in a nobler side.