A semi-empirical procedure is developed to determine the presence of white layer formation in AISI 1045 annealed steel. The procedure tries to capture both thermal and mechanical effects on white layer formation. Machining tests are conducted over a wide range of cutting speeds and flank wear. Microstructure and cutting force data are obtained from the tests and analyzed. Analysis of the data indicates a possible correlation between white layer depth, the maximum workpiece surface temperature and the unit thrust force increase due to flank wear. In particular, the onset of white layer formation is found to be dependent on a critical combination of the maximum workpiece surface temperature and the unit thrust force increase. The semi-empirical procedure based on this critical combination of parameters is experimentally verified.