Influence of Compositions in Hob Material on Viscosity Effect of Base Oil and on Lubricity of Additives in Cutting Oil for Hobbing.

Abstract

This paper deals with investigating the relationship between compositions of hob materials and the viscosity effect of base oil, and the influence of compositions in hob material on lubricity of additives in base oil with a variety of viscosity. Experiments were carried out using a fly tool. Tool wear and finished surface roughness trended to be smaller with higher viscosity of base oil for all hob materials tested. Powder metal high-speed steel containing high vanadium and high cobalt with the high viscosity base oil showed the best performance in terms of reducing tool wear and improving surface roughness. Chlorinated fatty acid ester and tricresyl phosphate as additives were effective for hob materials containing low vanadium and low cobalt, and polysulfide and sulfurized fatty oil were effective for hob materials containing high vanadium and high cobalt.