TY JOUR TI INVESTIGATION OF CONTACT AREA AT STEEL C12M CUTTING BY MINERAL-CERAMICS VOK-71 KW turning KW hardened steel KW mineral-ceramics KW contact area KW mechanism of wear JO Bulletin of Bryansk state technical university AU Sekletina, L.S. AU Yanyushkin, A.S. AU Gartfel'der, V.A. AU Yanyushkin, A.R. PY 2019 IS 2019 PB Bryansk State Technical University