Influence of different cooling strategies during hard turning of AISI 52100-part I:thermo-mechanical load,tool wear,surface topography and manufacturing accuracy

摘要

This paper presents a characterization of the turning process for finishing of AISI 52100 in martensitic heat treatment state at various cooling conditions.With regard to the cooling conditions,LN2-cooling,CO2 snow cooling at varied mass flows,sub-zero metalworking fluids(MWF)at varied supply temperatures,and dry machining were examined.The tool temperatures,the process forces,the tool wear,the surface topography as well as the dimensional deviations of the workpiece caused by unintended alterations of the depth of cut due to a thermal expansion or contraction of the workpiece are analyzed.The application of MWF supplied at 20 °C results in an unchanging thermo-mechanical load in the tool-work interface and surface topography as well as in a high manufacturing accuracy.Dry machining leads to an increasing depth of cut of up to 10 %,resulting in radial dimensional errors.Cryogenic machining and using the sub-zero MWF supplied at-30 °C exhibit a different behavior due to high cooling effects:the depth of cut is reduced up to 10 %,also leading to radial dimensional errors.However,even though the depth of cut and thus the undeformed chip cross section is affected by up to 10 % depending the cooling condition,the mechanical load remains approximately constant during single cuts.In part II,the surface and near surface microstructure morphology of the workpieces is characterized.