Effect of B Content on Microstructure and Wear Resistance of Fe-3Ti-4C Hardfacing Alloys Produced by Plasma-Transferred Arc Welding

Abstract

The Fe-3Ti-xB-4C (x = 1.71, 3.42, 5.10, 6.85 wt. %) hardfacing alloys are deposited on the surface of a low-carbon steel by plasma transferred arc (PTA) weld-surfacing process. Microstructure, hardness and wear resistance have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Rockwell hardness tester and abrasive wear testing machine, respectively. The results show that the microstructure in all alloys is composed of austenite, martensite, Fe23(C,B)6, Ti(C,B) and Fe2B. The volume fraction of eutectic borides and Ti(C,B) carbides increases with increasing B content. Many brittle bulk Fe2B phase arises when the boron content increases to 6.85%, which causes the formation of microcracks in the hardfacing layer. The microhardness of the hardfacing alloys is significantly improved with the B addition, however, the wear resistance of hardfacing alloys increases firstly and then decreases with increasing of B content. The hardfacing alloy with the 5.10% B content has the best wear resistance, which is attributed to high volume fraction of eutectic borides and fine Ti(C,B) particles distributed in the austenite and lath martensite matrix with high hardness and toughness. The formation of brittle bulk Fe2B particles in the hardfacing alloy with the 6.85% B leads to the fracture and spalling of hard phases during wear, thus, reducing the wear resistance.

Study of Additive Manufacturing of Hastelloy X Using Plasma Arc Welding Technology

“…A similar microstructure was observed with Cobalt-based alloy where Ti-based carbides exist with Cobalt dendrites [67]. In the Fe-3Ti-4C sample, Ti-based carbides distributed in the entire sample and no dendritic structure was reported [68].…”

Effect of Nb Content on the Microstructure and Wear Resistance of Fe-12Cr-xNb-4C Coatings Prepared by Plasma-Transferred Arc Welding

“…On the other hand, formation of these carbides reduces the carbon concentration in the matrix of the hardfacing alloy, which is favorable for improving the toughness. Some meaningful and interesting results have been reported in this area [14][15][16][17][18][19]. For example, Zhang et al [20] investigated the effect of Nb content on the microstructure of Fe-Cr-C coatings, and discovered that Nb can not only promote the formation of equiaxed grains, but also Coatings 2020, 10, 585 2 of 11 make the microstructure become finer.…”

Evolution of the Microstructure and Properties of Pre-Boronized Coatings During Pack-Cementation Chromizing

“…Surface coating techniques (such as hard coatings and solid lubricating coatings prepared by thermo-diffusion, spraying, plating, etc.) are the main means used to improve the surface properties of materials [1][2][3][4][5][6][7]. Thermo-diffusion coating treatments, such as carbonizing, nitriding, boronizing, and chromizing, are effective techniques for the protection of metal materials from wear and/or corrosion [8][9][10][11][12].…”