Tool wear investigation whilst turning BS970-080A15 carbon steel using TiCN-Al_2O_3 CVD coated carbide tooling in gaseous and liquid nitrogen environments

摘要

Purpose - The purpose of this work is to investigate the performance of non-contaminating metal cutting environments and investigate the associated tool chip interface conditions. The work benchmarks flood coolant characteristics and considers gaseous cutting environments as possible alternatives. Design/methodology/approach - Cutting trials were undertaken for a range of cutting environments. Flood coolant was investigated as was dry cutting, compressed air, room temperature nitrogen and liquid nitrogen environments. A range of cutting variables was measured in order to document the effect of cutting environment. Findings - The gaseous component of the liquid nitrogen environment limited the adhesion on the tool face to a region along the flank edge of the tool, shifting rake face conditions from seizure to that of sliding. Tighter chip curl, shorter contact lengths, reduced adhesion and lower feed forces are evidence that liquid nitrogen is acting as a "liquid inert barrier" beneath the chip within the tool/chip interface. Research limitations/implications - Only one tool work combination has been investigated. More tool work combinations will need to be investigated. Practical implications - The work demonstrated that it is possible to use environmentally safe environments during metal cutting operations. This reduces the exposure of the environment and machine tool operatives to compounds which have been shown to have detrimental effects on the environment and human health. Originality/value - The work has led to presenting a hypothesis that liquid nitrogen acts as a "liquid inert barrier" beneath the chip within the tool/chip interface.