Ranking of materials by their machinability applying a short term test

Paper i proceeding, 2008

For case hardening steel, the relationship between microstructure and machinability is investigated. To be able to determine the influence of morphology, i.e. grain size, phase distribution and interlamellar spacing in pearlite, homogeneous material is required. However, a homogeneous microstructure can only be guaranteed when small material volumes are used. For that reason the Volvo Standard Machinability Test has been applied, as it allows ranking of materials with respect to their machinability by removing only small amounts of material (~800 mm of a bar with 50 mm diameter for each material). In addition to what is described in the standard of the test, a number of observations and experiences have been made. In this article the observations in connection with the Volvo Standard Machinability Test are critically discussed. Furthermore, the results of the machinability test of the case hardening steels are presented.