Sequential four-ball study of some lubricating oils

A study of several oils was conducted using the Sequential Four-Ball Test ( SQFBT). The SQFBT was-developed to simulate results obtained in a full-scal e hydranlic pump stand test and off-high-way vehicle field tests. The Delta scar, the increase in wear over the Hertz elastic indentation value, was u sed to evaluate wear and scuffing characteristics of the fluids tested. A s eries of ASTM round-robin hydraulic test fluids were evaluated and the resu lts of the SQFBT agreed with pump stand test results, In addition, several commercial oils and some base fluids were evaluated to demonstrate the abil ity of the SQFBT test to be used as a research or screening tool. The base fluids evaluated included synthetic fluids, natural oils, and mineral oils. Some-friction and wear data were evaluated statistically to obtain repeata bility and reproducibility of the SQFBT. Differences in chemical structure are shown to affect friction and wear results.