Sandvik Ab

Sandvik Intellectual Property Ab

Leif E Akesson

Ake Ostlund

Per Gustafson

Susanne Norgren

Carl-Johan Maderud

Ulf Oscarsson

Anders Stenberg

Elias Forssbeck Nyrot

Jan Engqvist

Mats E Sjostrand

Jan N Lindstrom

Asa K Nystrom

Ulf Oskarsson

A cutting tool made of a cemented carbide substrate of WC, a metallic binder phase and gamma phase is provided. The cemented carbide has a well distributed gamma phase and a reduced amount of abnormal WC grains. The cutting tool has a more predicted tool life and an increased resistance against plastic deformation.

Cutting tool

A coated cutting tool of a cemented carbide substrate made of WC, a metallic binder phase and a gamma phase has a well distributed gamma phase and a reduced amount of abnormal WC grains. Further, the coated cutting tool is provided with a CVD coating of TiCN and an &#x3b1;-AlOlayer, wherein the &#x3b1;-AlOlayer exhibits a texture coefficient TC(0 0 12)&#x2265;7.2 and wherein in the ratio I(0 0 12)/I(0 1 14)&#x2265;1. The coated cutting tool has an increased resistance against plastic deformation. whilst maintaining toughness.

Coated cutting tool

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

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.

Cemented carbide with binder phase enriched surface zone

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.

A coated body consisting of a substrate that can be decarburized during a carbide, nitride or carbonitride coating process comprising a first (innermost) carbon diffusion retarding coating of MetCO, MetCON, MetON adjacent to the substrate and a second (next innermost) wear resistant coating of MetC, MetN and/or MetCN, where Met is Ti, Hf, V, Zr, Si, B or other metals of subgroup 3-7 of the periodic table of the elements, or a mixture thereof. The intermediate coating has been found beneficial in order to reduce or even eliminate the formation of eta phase in the substrate.

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Alvsjo, Sweden

Leif E Akesson