Predicting a Material's Machining Characteristics Using Flow Stress Properties Obtained from High-Speed Compression Tests

Abstract

A theory is given for calculating chip geometry, cutting forces, etc., from fundamental work material properties and cutting conditions. The flow stress properties of the work material (0·16 per cent carbon steel) used in the analysis are taken from high-speed compression test results. The theory predicts the main trends observed in machining experiments and a limited comparison with experimental results shows good quantitative agreement. A possible explanation for the occurrence of a built-up edge, involving the dynamic strain ageing (blue-brittleness) of the chip along the tool-chip interface, is considered and found to be consistent with the results.

Modelling orthogonal machining of carbon steels. Part II: Comparisons with experiments

“…5 is their flow stress at unit strain determined from high-speed compression tests. The portion AB was attributed to blue-brittleness but the more striking feature is the overlapping of the present Zerilli-Armstrong and [10] curves over the T mod range 200-700 K. There are however large differences at higher values of T mod . It draws attention to the need for more understanding of flow stress and friction in this highest temperature range.…”

“…The portion 'de' comes from Gauss points at which the temperature was above T c . The flow stress at unit strain from the previous work by Hastings et al [10] has been added to the figure and is discussed in Section 5.…”

“…In [10] they consider, for a steel of similar carbon content to 070M20, flow in the high temperature conditions next to the rake face, which determines chip/tool friction stresses. The dashed line in Fig.…”

“…There is an earlier analytical machining literature, associated with the name of Oxley [9], with particular researches jointly with Hastings et al [10] particularly relevant to this paper. The present paper's results in relation to these earlier studies are discussed.…”

Towards cutting force evaluation without cutting tests

“…Among the first, in 1950, Lapsley et al [2] tried to use tensile data, but the analysis was done only for one material. Later, Hastings et al [3] compared cutting forces with high-speed compression test data from the literature, and also for a single material. In 1985, Armarego and Whitfield [4] mentioned that many researchers tried without success to eliminate cutting experiments from cutting force prediction, slowing down research efforts in this way.…”