Abstract
Free-cutting steel, SAE 1113, in the annealed, and SAE 1115 and SAE 4135 in the cold-rolled condition were studied in orthogonal metal cutting. The feed was varied from 0.002 to 0.010 ipr and the rake angle from 20 to 40 deg, at a surface speed of 30 fpm, using several cutting fluids. This range of rake angles and feeds was in the practical region and permitted obtaining continuous chips. When examining the current theories on the shear angle ϕ, rake angle α, and friction angle β-relationships, it was found that none was in complete agreement with the experimental results. However, the equation λ = ϕ + β − α = const was found to hold approximately for the limited range of variables investigated. It was further found that the friction process on the tool face can be satisfactorily explained as a metal-shearing process, and that the ratio of the shearing stresses on the shear plane and tool face was approximately constant for the experimental data obtained.
