Sandvik Ab

Sandvik Intellectual Property Ab

Per Gustafson

Ake Ostlund

Leif E Akesson

Per Lindskog

Ulf Oscarsson

Bj&ouml;rn Ljungberg

Björn Ljungberg

Marco Zwinkels

Leif Kesson

Per Mårtensson

&angst;ke &Ouml;stlund

Anders Karlsson

Åke Östlund

Mikael Lagerquist

Chris Chatfield

Gunilla Anderson

Peter Björkhagen

Ulf Oskarsson

The present invention relates to a method of making cutting tools comprising a substrate having a hard phase and a binder phase, the method comprising forming green powder compacts using powder metallurgical techniques, charging the green powder compacts, placed on one or several trays, in a furnace and sintering the green powder compacts wherein the furnace comprises an insulation package, at least three individually controlled heating elements located inside the insulation package including a vertical heating element, an upper horizontal heating element arranged in an upper part of the furnace, and a lower horizontal heating element arranged in a lower part of the furnace, wherein operating the at least three heating elements such that an average controlled cooling rate from a sintering temperature down to at least a solidification temperature of the binder phase is 0.1-4.0&#xb0; C./min, and a sintering furnace operable to obtain a controlled cooling rate.

Sintering furnace and method of making cutting tools

The present invention discloses coated cutting tool inserts particularly useful for turning of nodular cast iron preferably at high speeds, comprising a cemented carbide substrate comprising from about 5 to about 9 wt-% Co and from about 1 to about 5 wt % cubic carbides and balance WC of 86-94 wt-%, and a coating comprising a first layer of TiCNOwith equiaxed grains, a layer of TiCNOwith a thickness of less than about 10 to about 15 &#x3bc;m with columnar grains, a layer of TiCNOwith a thickness of from about 0.1 to about 2 &#x3bc;m and with equiaxed or plate-like grains, a layer of &#x3b1;-AlOwith thickness from about 3 to about 8 &#x3bc;m, an outer layer of a multilayered structure of TiN+TiC with TiC being the outermost layer and a total thickness of from about 0.5 to about 2 &#x3bc;m and wherein the outer coating layer has been removed in the edge line and on the rake face so that the &#x3b1;-AlOlayer is on top along the cutting edge line and on the rake face and the outer TiC layer is the top layer on the flank face.

Coated cutting tool insert

A coated turning insert particularly useful for turning in stainless steel is disclosed. The insert is characterized by a WC&#x2014;Co-based cemented carbide substrate having a highly W-alloyed Co-binder phase and a coating including an inner layer of TiCNOwith columnar grains followed by a layer of fine-grained, &#x3ba;-AlOand a top layer of TiN. The layers are deposited by using CVD methods.

Coated turning insert and method of making it

The present invention relates to method of making a cemented carbide insert, comprising a cemented carbide substrate and a coating. The substrate contains WC and cubic carbonitride phase in a binder phase based of Co and/or Ni and has a binder phase enriched surface zone essentially free of cubic phase. The binder phase enriched surface zone prevails over the edge. By sintering in an atmosphere essentially consisting of nitrogen the thickness of the binder phase enriched zone can be controlled.

Method of making cemented carbide with binder phase enriched surface zone

A coated turning insert particularly useful for turning in stainless steel is disclosed. The insert is characterized by a WC&mdash;Co-based cemented carbide substrate having a highly W-alloyed Co-binder phase and a coating including an inner layer of TiC,N,O,with columnar grains followed by a layer of fine-grained &kgr;-Al,O,and a top layer of TiN. The layers are deposited by using CVD-methods.

The present invention discloses a method of sintering of cemented carbide or cermet bodies lying on graphite trays. By using graphite trays coated with a covering layer of Y.sub.2 O.sub.3 containing .ltoreq.20 wt-% ZrO.sub.2, or corresponding volumetric amount of other refractory oxides, e.g., Al.sub.2 O.sub.3 or combinations thereof, with an average thickness of .gtoreq.10 .mu.m, the life of the trays between regrindings and recoatings can be largely extended.

Sintering tray

A cemented carbide insert with improved toughness and resistance against plastic deformation containing WC and cubic phases of carbide and/or carbonitride in a binder phase based on Co and/or Ni with a binder phase enriched surface zone is disclosed. The binder phase content in the insert is 3.5-12 weight-%. In a zone below the binder phase enriched surface zone, the binder phase content is 0.85-1 of the binder phase content in the inner portion of the insert and the content of cubic phases is essentially constant and equal to the content in the inner portion of the insert. The insert is formed by sintering a cemented carbide containing a nitrogen-containing material in a vacuum or inert atmosphere and heat treating the sintered insert in nitrogen at 40-400 mbar at a temperature of 1280.degree.-1430.degree. C. for a time of 5-100 min.

Process for making a cemented carbide with binder phase enriched surface

The present invention relates to a cemented carbide insert, comprising a cemented carbide substrate and a coating. The substrate contains WC and cubic carbonitride phase in a binder phase based of Co and/or Ni and has a binder phase enriched surface zone essentially free of cubic phase. The binder phase enriched surface zone prevails over the edge. As a result, an insert according to the invention has improved edge toughness and resistance against plastic deformation and is particularly useful for machining of sticky work piece materials such as stainless steel.

Cemented carbide with binder phase enriched surface zone

There is disclosed a new process for binder phase enrichment. The process combines binder phase enrichment by dissolution of cubic phase with the requirements that cause formation of stratified layers, resulting in a unique structure. The new structure is characterized by, in comparison with the ones previously known, deeper stratified layers and less maximum binder phase enrichment. The possibility of combining dissolution of the cubic phase with formation of stratified layers offers new possibilities to optimize the properties of tungsten carbide based cemented carbides for cutting tools. The new process offers possibilities to combine the two types of gradients. The dissolution of cubic phase moves the zone with maximum mount of stratified binder phase from the surface to a zone close to and below the dissolution front. By controlling the depth of dissolution, the interstitial balance and the cooling rate, a cemented carbide with a unique combination of toughness and plastic deformation resistance can be achieved.

A cemented carbide insert with improved toughness and resistance against plastic deformation containing WC and cubic phases of carbide and/or carbonitride in a binder phase based on Co and/or Ni with a binder phase enriched surface zone is disclosed. The binder phase content in the insert is 3.5-12 weight-%. In a zone below the binder phase enriched surface zone, the binder phase content is 0.85-1 of the binder phase content in the inner portion of the insert and the content of cubic phases is essentially constant and equal to the content in the inner portion of the insert.

Cemented carbide inserts are available containing WC and cubic phases of carbide and/or carbonitride in a binder phase based on cobalt and/or nickel with a binder phase enriched surface zone. The binder phase content along a line essentially bisecting the rounded edge surfaces increases toward the edge and cubic phase is present. As a result, the edge toughness of the cutting inserts is improved.

Cemented carbide with binder phase enriched surface zone and enhanced

There is disclosed a new process for binder phase enrichment. The process combines binder phase enrichment by dissolution of cubic phase with the requirements that cause formation of stratified layers, resulting in a unique structure. The new structure is characterized by, in comparison with the ones previously known, deeper stratified layers and less maximum binder phase enrichment. The possibility of combining dissolution of the cubic phase with formation of stratified layers offers new possibilities to optimize the properties of tungsten carbide based cemented carbides for cutting tools. The new process offers possibilities to combine the two types of gradients. The dissolution of cubic phase moves the zone with maximum amount of stratified binder phase from the surface to a zone close to and below the dissolution front. By controlling the depth of dissolution, the interstitial balance and the cooling rate, a cemented carbide with a unique combination of toughness and plastic deformation resistance can be achieved.

Growing community of inventors

Huddinge, Sweden

Per Gustafson