Cubic boron nitride cutting tool

US6090476A · kind A · utility

Assignee

• SANDVIK AB · SE

Inventors

• Michael Thysell · Stockholm, SE
• Torbjorn Selinder · Stockholm, SE

Key dates

• Filing date: Dec 18, 1997
• Grant date: Jul 18, 2000
• Expiry date: Dec 18, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/265
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A multilayer coated cutting tool comprising a cemented carbide body with at least one sintered-on inlay containing polycrystalline cubic boron nitride forming at least one cutting edge. Reduced crater wear of the rake face of the tool is achieved by reducing chemical interaction between tool and workpiece/chip material, and used edges of indexable inserts can be readily identified. The tool is provided with a multilayer coating by thermal CVD, the coating including (1) a first, innermost, layer of TiC.sub.x N.sub.y O.sub.z with x+y+z=1, with y>x and z<0.2, with equiaxed grains with size <0.5 .mu.m and a total thickness <1.5 .mu.m, (2) a second layer of TiC.sub.x N.sub.y O.sub.z with x+y+z=1, preferably with z=0, x>0.3, most preferably x>0.5, having a thickness of 1-8 .mu.m, with columnar grains, and (3) a third layer of a smooth, fine-grained (grain size about 1 .mu.m) layer of (.alpha.-Al.sub.2 O.sub.3 or .kappa.-Al.sub.2 O.sub.3 or mixtures thereof, with a thickness of 2-10 .mu.m.