Spray forming of supermartensitic stainless steel for oil exploration pipes coating

Abstract

The oil industry, since the early 90s, has encouraged the development of corrosion-resistant alloys, economically viable for use in risers and pipes for oil extraction. The major flailure cause in a riser drilling is associated with the wear of its internal wall, caused by the contact between the connections, drill pipes and the risers inner walls. DEMa has a project in development, "Hardness and wear resistance of alloys based on iron amorphous / nanostructured used for coating equipment for the oil industry". Petrobras support it with resources, coordinated by the supervisor of this proposal, which aims at a comprehensive study about corrosion-resistant alloys resistant and simultaneously wear it to application in offshore structures, in particular, the pre-salt. This work fits in this context and aims to evaluate the wear resistance, both abrasive and adhesive, of a supermartensitic stainless steel (a good mechanical properties alloy, with corrosion resistant and considerably cheaper than steels with high contents of Ni and Cr, as duplex and superduplex, for example) conformed by spray. It will be studied also the influence of adding boron in the steel composition, which are expected an improvement in abrasive wear resistance due to dispersed phases of high hardness (borides) formation. The spray forming will be made in the Laboratório de Fundição (LabFun) equipment in the Materials Engineering Department (DEMa) at the Federal University of Sao Carlos. The deposits obtained will be characterized by chemical analysis, optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and hardness. The wear resistance will be measured on rubber wheel type (abrasive wear tests), and the testing pin-on-disc (adhesive wear), according to the ASTM G65-04 and ASTM G99-05, respectively. (AU)