Study of the rotating arc on the tribological behavior of hardbanding for oil drilling tubes

In this work, four welded coupons were evaluated with a welding speed of 5, 9, 11 and 13 mm/s. A semi-automatic welding process was used under gas protection, using a 1.6 mm diameter tubular wire. The chemical composition was analyzed on each welded coupon, the dilution percentage was determined, the dimensional of the beads was carried out and the microstructure was characterized by optical microscopy and scanning electron microscopy. In addition, the Vickers microhardness HV 2 in the middle of the bead were measured. It was found that the dilution decreased up to 22% (a decrease of 80% compared to traditional welds). Furthermore, the beads presented less refusion with the base material, increasing their width and penetration. A microstructure formed by an “α matrix” was observed, with complex metallic carbides and carboborides which increased in quantity when considering the effects of the rotating arc method Also, it was observed a microstructure formed by a matrix α with complex metal carbides and carboborides that increased in quantity with the effect of the rotating arc. The hardness of the beads varied between 720 and 780 HV 2 . The weight loss and the friction coefficient decreased with the application of the arc rotation. These changes would be related to the increase in non-metallic phases.