Abstract
Alloy steel (SNCM5) was cut with carbide tool S2 applying various cutting fluids and wear process on tool face (crater and flank wear) was observed. By observation of wear process, choicing standards for cutting fluids at high speed cutting were obtained. Those areas follows :
1) Lubricating property is more predominant for tool wear than cooling property.
2) Extreme pressure cutting oil is not good since it increases tool wear for its high chemical reaction.
3) Non water soluble oil is generally not good since it smokes very much though it has good lubricating property.
4) Concretely, recommended cutting fluids are emulsion type and soluble type.
