Abrasive-tool wear and the machinability of high-speed tungsten-free steels

Resumo

The physics of grinding is considered in order to explain the difference in machinability of tungstenfree and tungsten steels. The strength of the most common steels and alloys is studied over a broad range of strain rate and temperature. Analysis of the results established the variation in strength of high-speed tungsten-free and tungsten steels in typical grinding conditions and permits explanation of the difference in machinability of the steels in physical terms. The relation between the machinability of steel and wear of the abrasive tool is investigated in experiments with individual grains (plane angle ϕ = 90°) of different abrasive materials: electrocorundum (24A), zirconium corundum (38A), and Elbor (Borazon). That permits the derivation of a regression equation reflecting the qualitative characteristics of the process, such as the starting point, the presence of an extremum, and the asymptotic behavior.