XXX-X-XXXX-XXXX-X/XX/$XX.00 ©20XX IEEE Tribological study of the stainless steel coating multilayer for ball valves application Khaled Chemaa Department of mechanical engineering Yahia Fares University Medea, Algeria Khaledchemaa@yahoo.com Mohamed Kezrane Department of mechanical engineering Yahia Fares University Medea, Algeria mohamedkezrane@yahoo.fr Salim Hassani Center for development of advanced technologies (CDTA) MIL Division Algiers, Algeria shassani@cdta.dz Abstract— Ball valves made by stainless steel alloys are subjected to severe wear and corrosion during their services in aggressive environments. The present study is aimed to study the tribological behavior of stainless steel multilayer coating with number of layers varied from 1 to 4 for future application on ball valves. Surface roughness was reduced when increasing the number of layers from 1 to 4. Tribological analysis showed that both the coatings with 3 and 4 layers have the lowest friction coefficients and that the coating with 4 layers present a low wear. Keywords— Stainless steel, Coatings, Tribology I. INTRODUCTION Ball valves presented in Fig.1 are widely used in oil and gas industry in piping systems to control flowrates and flow directions or to cut off the flow in pipelines [1]. Fig. 1. Ball valve Generally, ball valves are made by stainless steel alloys (mainly 304 and 316 alloys), unfortunately, stainless steel alloys are featured with low wear resistance and hardness which make them not fully suitable to resist at aggressive environments without using some expensive coatings [2]. Figure 2 shows a ball valve with worn surface after just few days of service. Introducing a ball valve manufactured from carbon steel alloy and coated with a wear resistant stainless steel coating will offer an interesting transition in ball valves industry. Due to their low processing cost, while presenting acceptable oxides amount and low porosity [3], twin-wire arc spray process can be considered as the most commercial used thermal spray process [4]. The aim of the present work is to study the tribological properties of stainless steel multilayers coatings on ball valves made from carbon steel alloy with the variation of the number of layers from one to four. Fig. 2. Ball valve with a worn surface II. MATERIALS AND METHODS EN 10025-2 carbon steel was used as substrate with 10 mm of diameter. The substrates were polished and grit blasted with grease cast iron grits with 0.4 mm in diameter. Commercial AISI 304L stainless steel wires with 1.6 mm in diameters were used as feedstock. The nominal composition of the 304L wire is: 0.08 wt% C, 2.00 wt% Mn, 0.030 wt% S, 1.00 wt% Si, 0.045 wt% P, 8.00 wt% Ni, 18.00 wt% Cr and balance of Fe. The stainless steel coatings were produced by twin-wire arc spray system (Metallisation ltd, UK) with an arc spray gun of Arcspray 234 type. The spraying parameters are given in table 1. The coatings phases’ analyses were carried out by X- Ray diffraction (XRD, Bruker D8 Advance, Germany). The coatings cross-sections were analyzed by Scanning Electron Microscopy (SEM, FEI Quanta 650, USA).