Development of an aggregate indicator to assess the machinability of steels

A methodology for the machinability assessment of steel is proposed based on the direct measurement of cutting forces and surface roughness, along with the development of an aggregate machinability indicator. Experimental work for the verification of the validity of this testing scheme was carried out at different cutting condition combinations using three grades of steel, namely, 1018 (Low Carbon, Cold-Rolled Steel), 304 (Austenitic Stainless Steel), and 4140 (Low-Alloy Steel) and uncoated carbide inserts as the tool material. Mathematical models are developed for predicting the forces acting on the tool for different cutting conditions and materials. The test results show that the developed indicator provides a number of advantages: (1) an adequate estimate of a material’s machinability; (2) a cost effective method for machinability testing.