Protection of threaded connections against corrosion

Abstract

The paper presents data on the effect of the addition of D-10TM oligomer in the composition of standard lubricants for processing threaded connections on the degree of corrosion damage, the value of the torque for unscrewing and the value of friction coefficient in threaded connections. The addition of D-10TM oligomer 5% by weight in Litol-24 helps to reduce the torque for unscrewing threaded joints by 1.5-1.7 and 1.3-1.4 times in comparison with G-SKa 2/6-2 Grease and Lithol-24 respectively, therefore, reduces the coefficient of friction in threaded connections by the same amount. When examining the threaded part of fasteners after disassembling the joints pre-treated with the developed composition, traces of corrosion appear only after 720 hours, and in joints treated with G-SKA 2/6-2 Grease and Lithol-24 – after 96 hours. Production tests showed that the developed composition improves the disassembly of the threaded connection by 1.3-1.4 times in comparison with factory processing. The improvement of the protective properties of the composition with the addition of the D-10TM oligomer is explained by the fact that the D-10TM oligomer, having polar urethane groups in the chain and a high molecular weight, exhibits strong intermolecular interactions due to the formation of hydrogen bonds. Its three-dimensional spatial structure provides better filling of cracks and gaps in the threaded joint, seals them, isolates them from aggressive environments and thus provides better protection against corrosion.