Coated cutting insert and method of manufacture thereof
AssigneeSandvik AB
InventorsBjorn Ljungberg, Leif kesson
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Abstract
A coated cutting insert particularly useful for intermittent cutting of low alloyed steel. The insert is characterized by a WC-Co-based cemented carbide body having a highly W-alloyed Co-binder phase and a coating including an inner layer of TiC.sub.x N.sub.y O.sub.z with columnar grains and an outer coating of a fine grained, textured .alpha.-Al.sub.2 O.sub.3 -layer.
Claims20
A cutting tool insert for machining of low alloyed steel, the insert comprising a cemented carbide body and a coating wherein said cemented carbide body consists essentially of, in weight %, WC, 5-11% Co and 0-10% cubic carbides of metals from groups IVb, Vb or VIb of the periodic table and a highly W-alloyed binder phase with a CW-ratio of 0.76-0.93 and said coating comprises a first layer of TiC.sub.x N.sub.y O.sub.z having a thickness of 0.1-2 .mu.m and equiaxed grains <0.5 .mu.m in size, a second layer of TiC.sub.x N.sub.y O.sub.z having a thickness of 2-15 .mu.m and columnar grains of about <5 .mu.m in diameter, a third layer of TiC.sub.x N.sub.y O.sub.z having a thickness of 0.1-2 .mu.m and equiaxed or needle-like grains .ltoreq.0.5 .mu.m in size, and a fourth layer of a smooth, textured, fine-grained .alpha.-Al.sub.2 O.sub.3 -layer with a thickness of 2-10 .mu.m and grain size of 0.5-2 .mu.m.
A method of coating a cutting insert comprising a WC-Co-based cemented carbide body, the method comprising:
- coating the body with a first layer of TiC.sub.x N.sub.y O.sub.z in a thickness of 0.1-2 .mu.m, and such that the first layer comprises equiaxed grains <0.5 .mu.m in size;
- coating the first layer with a second layer of TiC.sub.x N.sub.y O.sub.z in a thickness of 2-15 .mu.m and such that the second layer has columnar grains with a diameter of about <5 .mu.m, the second layer being deposited at a temperature of 850.degree.-900.degree. C. while using acetonitrile as the carbon and nitrogen source;
- coating the second layer with a third layer of TiC.sub.x N.sub.y O.sub.z in a thickness of 0.1-2 .mu.m and such that the third layer has equiaxed or needle-like grains .ltoreq.0.5 .mu.m in size;
- and
- coating the third layer with a fourth layer of a smooth textured .alpha.-Al.sub.2 O.sub.3 -layer textured in the direction (012), (104) or (110) with a thickness of 2-10 .mu.m.
A cutting tool insert for machining of low alloyed steel, the insert comprising a cemented carbide body and a coating, the body comprising a WC-Co-based cemented carbide body and said coating comprising a first layer of TiC.sub.x N.sub.y O.sub.z having a thickness of 0.1-2 .mu.m and equiaxed grains <0.5 .mu.m in size, a second layer of TiC.sub.x N.sub.y O.sub.z having a thickness of 2-15 .mu.m and columnar grains of about <5 .mu.m in diameter, a third layer of TiC.sub.x N.sub.y O.sub.z having a thickness of 0.1-2 .mu.m and equiaxed or needle-like grains .ltoreq.0.5 .mu.m in size, and a fourth layer of a smooth, textured, fine-grained .alpha.-Al.sub.2 O.sub.3 -layer with a thickness of 2-10 .mu.m and grain size of 0.5-2 .mu.m.
Dependencies are inferred from the claim text.