Abstract:A new type of lubricating oil additive of nitrogencontaining borate ester for aluminium rolling was synthesized.The film strength and friction coefficient of the aluminium rolling lubricating oil with nitrogencontaining borate ester were investigated by a fourball tester.The wear scar morphology was observed through microscope and wear scar diameters was measured.The influences of the type of base oil,the content of extreme pressure additive,the load and rotational speed on the tribological performances of aluminium rolling lubricating oils of nitrogencontaining borate ester were evaluated comprehensively by orthogonal test.The enhancing effects of four parameters on the tribological performances of aluminium rolling lubricating oils were studied synthetically based upon multiobjective optimal design.The results show that the content of extreme pressure additive has the greatest effect on the tribological performance of aluminium rolling lubricating oils,followed by the type of base oil,the rotational speed,and the load.Based on the multiobjective optimal design,the best parameter combination for the tribological performances of nitrogencontaining borate ester aluminium rolling oil was obtained,which is that the content of extreme pressure additive is 1.0%,the type of base oil is D100,the rotational speed is 1 200 r/min and the load is 294 N.The result of the range analysis and variance analysis shows that content of extreme pressure additive and the type of base oil have a significant effect on the tribological performances.