Development Of Fully Synthetic Non-Stained Bearing Oil-Air Lubricant For Aluminum Rolling Mills

In the process of aluminum rolling,the leakage of high viscosity roll bearing lubricant pollutes the low viscosity rolling process oil,which affects the surface annealing and cleaning performance of aluminum foil and reduces the surface quality of the product.There is a need for a nonstaining roll bearing lubricant to reduce the pollution of rolling process oil due to leakage,which has been studied at home and abroad but has not been completely solved.According to the field research and roll bearing lubrication working conditions,the base oil and additives of the lubricant are analyzed and researched,and a fully synthetic non-stained bearing oilair lubricant for aluminum mills is developed to meet the performance requirements.The main research work is as follows:1)For the performance requirements of the aluminum foil rolling process on the roller bearing lubricant,based on the theoretical analysis of the bearing lubrication base oil performance,the physical and chemical properties and formulation design of two polyether synthetic oil and a mineral base oil,the results show that the polyether synthetic oil has high flash point and high viscosity temperature performance,its viscosity index of 200 or more,polyether synthetic oil physical and chemical properties significantly better than the mineral base oil.It can ensure better fluidity and pumping ability at room temperature,and can form thicker oil film under high temperature conditions in the friction zone,which can reduce the friction and wear of bearings.2)The thermal stability and annealing cleaning performance of the oil samples were investigated by using thermogravimetric-differential scanning volume simultaneous analysis and annealing box method.The results showed that the pyrolysis of semi-synthetic bearing oil and mineral base oil was completed at a temperature of about 400*,and there were1.1%～2.2% residues;while the pyrolysis of polyether synthetic oil was completed at a temperature of 360*,which was 40* lower than that of semi-synthetic bearing oil and mineral base oil,and there were no residues.The oil box annealing method test which mimics the industrial annealing of aluminum foil also shows that the synthetic oil containing polyether has excellent annealing cleanliness on the surface of aluminum foil,and there is no oil spot after annealing of aluminum foil.This indicates that polyether synthetic oil is an ideal base oil for non-stained bearing lubricants.3)The tribological properties of the polyether base oil were analyzed and studied on a four-ball friction and wear tester and a comprehensive material surface property tester.The results showed that the maximum nonsnagging load of polyether base oil was 726 N and the sintering load was981 N,which were 14.0% and 24.9% higher than those of mineral base oil respectively,but they did not meet the requirements of roll bearing lubrication,so it was necessary to increase the extreme pressure anti-wear agent to improve the tribological performance of polyether base oil.Through a small amount of zinc dialkyl dithiophosphate(ZDDP,with friction reduction,anti-wear and antioxidant functions)and HQT9202 compound extreme pressure anti-wear agent can significantly improve the tribological properties of polyether base oil,but the compound extreme pressure anti-wear agent than ZDDP has less dosage,better performance characteristics.Adding only 1.5%wt compound to the polyether base oil,the maximum non-snagging load can reach 1117 N and the sintering load can reach 1962 N,and the wear scar diameter is only 0.34 mm after the long wear test at temperature 75℃,load 392 N and 1 hour,and the tribological performance is obviously better than the existing roll bearing oil-air lubricant.The mechanism of action of the extreme pressure anti-wear additive was analyzed based on energy spectrum analysis,explaining the reasons for the lower dosage and better performance of the additive package.4)Based on the formulation research results,two samples of No.1and No.2 non-staining oil-air lubricants were developed.In the comparison test with domestic high-performance bearing oil,No.2 nonstaining oil had a viscosity index of 190 and a return cleanliness of Class II,with excellent tribological properties.A 4-week industrial trial of polyether No.2 non-stained oil-air lubricant on a domestic high-speed cold rolling mill and aluminum foil roughing mill showed that it could better adapt to the oil-air lubrication needs on a medium rolling mill,reach the level of domestic high-performance roll bearing lubricant,and better extend the process oil change interval,reduce downtime and lower production costs.