Analysis of surface roughness and cutting force in WS₂-Assisted MQL turning of H13 steel

Purpose The main purpose of this work was to compare the turning performance of H13 steel while cutting with carbide tools under dry/MQL conditions. Furthermore, the impact of adding a solid lubricant into eco-friendly sunflower oil was studied, when machining under MQL condition. Design/methodology/approach Experiments were performed as per Taguchi L12 methodology. Cutting speed of 335–525 rpm, feed rate of 0.2–0.3 mm/rev and depth of cut of 0.2–0.3 mm were selected as input cutting parameters. Final outcomes in terms of average surface roughness and tangential cutting force were assessed under dry and MQL machining case. Under MQL case, the microparticles of tungsten disulfide (WS 2 ) were used as a solid lubricant and 1% concentration of it was added to sunflower oil to create nanofluid. Finally, the outcomes from MQL and dry cases were compared. Findings It was noted that using WS 2 mixed oil in MQL machining significantly reduced cutting forces (23.03%). Furthermore, in comparison to dry machining, the machined workpiece’s surface quality was enhanced (4.43%). Optical microscope images of surface roughness indicated fine feed marks with MQL case in contrast to wide feed marks under dry condition. Practical implications MQL turning with the use of WS 2 mixed cutting oil with selected parameters can be used in conventional machining industry to improve turning performance of H13 steel. Originality/value Turning of H13 steel with eco-friendly cutting oil (sunflower oil + WS 2 ) has not been explored earlier.