IMPROVEMENT OF THE WEAR AND CORROSION-RESISTANCE OF OIL PUMP MATERIALS USING PLASMA IMMERSION ION-IMPLANTATION

A typical oil pump used in oil wells consists of a piston column, pist on sleeve and bail valve. The working environment in an oil held is ha rsh and unforgiving, and the piston column in the oil pump is very vul nerable to wear and corrosion. Hence, improving the wear and corrosion resistance of the piston which is made of 45# steel is critical to th e efficiency and profitability of oil companies. Even though ion impla ntation is an effective means to enhance the surface properties of the materials, the irregular shape and large dimension of the column make conventional beamline ion implantation very difficult. As the techniq ue of plasma immersion ion implantation circumvents this line-of-sight restriction, it is a suitable technique to improve the wear and corro sion resistance of the components in an oil pump. A treatment process involving RF plasma nitriding and ion beam enhanced deposition (IBED) has been developed. The microhardness, mass loss due to wear, and coef ficient of friction of the untreated and treated samples were measured . A salt fog test was also conducted to evaluate the resistance agains t rusting. The results indicate that the treatment improves the wear a nd corrosion resistance of the 45# steel samples significantly, and th at the combined RF plasma nitriding and IBED process is more effective than a single RF plasma nitriding step. (C) 1998 Elsevier Science S.A .