Sliding bearings are critical components of the internal combustion engine. Friction and wear occur in the contact area between the shaft and the bearing. Significant wear can occur in poor working conditions or after a long service time, leading to the failure of the sliding bearing and affecting the reliability of the machinery. It is essential to investigate the wear performance of sliding bearings, understand their wear mechanism, predict their service life, and select wear-resistant materials and surface treatments. This paper reviews the current status and prospects of sliding bearing wear research, focusing on the classification of sliding bearing wear tests, wear testing machines, wear test research, wear prediction models, and future research prospects.
Oil and gas exploration is a sector which drives the global economy and currently contributes significantly to global economic development. The safety of subsea pipelines is deeply affected by factors such as pipeline buckling, corrosion and leakage. Once a subsea pipeline is seriously leaking or damaged, it will cause a lot of waste of resources at light level, and it will cause explosions in severe cases, resulting in heavy casualties and huge economic losses, and at the same time, seriously damaging the surrounding ecological environment. Therefore, it is necessary to pay attention to problems related to the buckling, corrosion and leakage of submarine pipelines. This paper consists of a literature review of the latest research about buckling, corrosion and leak detection.
The friction reduction mechanism of glycerol monooleate (GMO) was investigated under boundary lubrication with elevated temperature. Tribological performances were tested using reciprocating test rig by adding 5 wt.% GMO into Poly-alpha Olefin (PAO) base oil. Friction coefficient and wear were recorded during experiments. The used oil was evaluated by infrared detection after experiments. Results show that GMO could reduce friction coefficient at both low and high temperature. At elevated temperature, the friction coefficient of PAO-GMO blend climb up gradually, followed by a decrease tendency, and the wear increase gradually with temperature. The results of Quartz Crystal Microbalance show that the physical adsorption film plays the main role in friction reduction at low temperature. While at high temperature, the Infrared Spectrum and X-Ray Photoelectron Spectrum show that the GMO involves into the chemisorption with friction surface, producing Fe(OH)O and Fe3O4. The friction reduction mechanism of GMO transferred from physisorption to chemisorption, which reduced friction coefficient at both low and high temperature.
The friction performance of MoDTP in the existence of ester was investigated. Tribological experiments were performed on reciprocating test rig between CKS piston ring and cast iron cylinder liner. Experimental results show that ester concentration is a key factor that influences the performance of MoDTP, the competitive effects between MoDTP and ester also vary with test temperature and load, and the “V” shape friction coefficient curve is caused by the change in friction surface states. During friction, when the surface roughness decreased and liner surface is covered by the friction layer, fresh metal is less likely to expose to lube oil, which reduces the activity of MoDTP in the existence of high concentration ester.