Abstract
Coating effects of organic polarity substance, such as carboxylic acid, on the chip formation mechanism of orthogonal cutting have been investigated both for annealed irons and for work-hardened irons. Coating materials are non-polarity liquid paraffin, liquid paraffin containing 0.2mass% oleic acid and pure oleic acid. Cutting speed is 1.67mm/s and cutting depth is 0.02mm. The following results are obtained. 1) For work-hardened irons, 0.2mass% and pure oleic acid are effective for the decrease of cutting force, the improvement of cutting surface roughness, the thinning of chips and the decrease of lamella thickness in shear-type chips. 2) The above-mentioned phenomena are unable to be observed in annealed irons where chips are tear-type. 3) From the infrared spectrum measurement, the chemisorption between oleic acid molecules and Fe atoms is estimated at the area of high dislocation density such as upheaved region in front of cutting chip.
