Oil Drill Pipe Joint Surface Metal Ceramic Membrane Preparation And Its Performance Study

For the requirement of wear and corrosion resistance of drill pipe joints, and to improve the service life, this article chose metal ceramic materials which have excellent wear and corrosion resistance composed of nitrides, carbide and oxide of Ti, Cr and Al as the coating materials, and prepared multi-layer metal ceramic films on the surface of drill pipe joint materials (37CrMnMo). The micro-structure, bonding property, friction and wear performance, and corrosion resistance of the metal ceramic samples were investigated by the combination methods of testing and material modern analysis and testing technology.Dense and homogeneous metal ceramic films have been generated on the surface of drill pipe joint materials by chemical vapor deposition (CVD). The metallographic structure of the coating sample matrix (JR) without quenching and tempering treatment is proeutectoid ferrite and pearlite; and the metallographic structure of the coating sample matrix (JZ) with normalizing before coating is the single slice layer pearlite; while, the metallographic structure of the quenching and tempering sample (JRR) matrix is tempered sorbite, this structure can reduce the influence of high temperature during CVD process on matrix structure, which ensure the metal ceramic samples have a good comprehensive performance after CVD. After the CVD metal ceramic coating treatment, the metal ceramic coatings with the total thickness of about10μm have generated on the drill pipe joint material. The films are muti-layer metal ceramics, and each film contains a little amount of Cr. The phase structures of muti-layer metal ceramics are Al2O3, Al1.92Cro.o8O3, CrAl17, C0.7N0.3Ti and TiC.The scratch test reveals that the comparison relationship of bonding property of different samples is showed as follows:JRR> JR> JZ. There is no shedding on the edges of scratches, which shows the good bonding property.The results of friction wear property test reveal that the quenching and tempering sample numbered as JRR has the good wear resistance, and it can even replace the wear-resisting belt of drill pipe.The results of slow strain rate test (SSRT), electrochemical test and high temperature pressure corrosion test reveal that hardening and tempering after coating is beneficial to improve the corrosion resistance of coating materials. And the corrosion resistance after coating is more superior to the samples without coating; the excellent corrosion resistance of samples was in the order of JRR>JR>JB. After CVD treatments, dense and homogeneous ceramic films were generated on the surface of joint materials. Dense ceramic films are without cracks or other defects of organization structure, and it has a good bonding property, so it can effectively prevent harmful atoms or ions from contacting directly with the matrix. Especially, metal ceramic films can effectively prevent hydrogen evolution reaction of H2S, CO2and the steel, which would generate harmful hydrogen atoms. Even if hydrogen atoms have produced, ceramic films can effectively prevent from hydrogen blistering and hydrogen induced cracking by separating hydrogen atoms from metal substrate.