| 摘要 |
PROBLEM TO BE SOLVED: To improve milling machining performance of stainless steel by making a covering cemented carbide body including a EC-Co base of a specific composing region, the extreme inner thin TiN layer, a TiAlN layer having a periodical change of a Ti/Al ratio vertically on a base/coating interface and the extreme outside TiN layer of WC crystal grains of specific size. SOLUTION: A high speed covering cutting tool insert for milling machining stainless steel at high speed cutting speed/containing a cemented carbide body with WC-Co as its main component containing a small amount of Cr and having 10-12 mass % of Co., favourably 10-11 mass % of Co, 0.3-0.6 mass % of Cr, favourably 0.4-0.5 mass % of Cr and WC-Co composition with the remainder made of WC is provided. At this time, average WC crystal grain size is within a region of 1.0-1.6μm, favourably 1.1-1.4μm. Crystal grain size of WC receives remarkable influences by Cr density. A cemented carbide base is devised to have a CW ratio of 0.89-0.93 to improve cutting performance. |
