Composition for Anticorrosive Treatment of Parts of Threaded Connections

Abstract

Introduction. A review of studies on the protection of threaded connections from corrosion shows that they have leaks that contribute to the development of crevice corrosion, which leads to a decrease in the mechanical strength of threaded connections and complicates dismantling. Modern lubricants and chemical thread fixatives do not provide corrosion protection and disassembly of threaded connections over a long service life, so the development of a more effective lubricant composition is an urgent task. Aim of the Article. Is to develop an effective lubricant composition to protect against corrosion and improve the disassembly of threaded connections. Materials and Methods. The parts of the M10 threaded pair with a thread pitch of 1.5 mm made of St3 steel, connecting two products, (prototypes) were lubricated with grease Zh-SKa 2/6-2, lithol-24, grease + oligomer D-10TM 5% by weight, composition of litol-24 + oligomer D-10TM 5% by weight, tightened to the moment of tightening force 80 N‧m, immersed in a 3% hydrochloric acid solution at a temperature of 22‒24°С. After 8 hours, the samples were removed from the solution and left in the air for 16 hours, which represented one cycle. According to the lubrication options, the number of parallel experiments was 5. Exposure duration – 24; 48; 96; 240; 480; 720 hours, after the expiration of which 5 samples of each lubricant option were disassembled, the value of the moment of the release force was recorded, the corrosion damage was assessed, and the coefficient of friction was calculated. Results An effective lubricant composition has been developed for processing parts of threaded connections, which increases their corrosion resistance and improves dismantling. Discussion and Conclusion. When adding oligomer D-10TM 5% by weight in litol-24, there is a significant increase in the length of time before the appearance of foci of corrosion on the details of threaded connections and an improvement in their dismantling. Implementation of the obtained results allows to increase the reliability of threaded connections.