Abstract:
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° C./min, and a sintering furnace operable to obtain a controlled cooling rate.
Abstract:
According to the present invention there is provided a method of making a finegrained tungsten carbide—cobalt cemented carbide comprising mixing, milling according to standard practice followed by sintering. By introducing nitrogen at a pressure of more than 0.5 atm into the sintering atmosphere after dewaxing but before pore closure a grain refinement including reduced grain size and less abnormal grains can be obtained.
Abstract:
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.
Abstract translation:本发明公开了一种烧结石墨盘上硬质合金或金属陶瓷体的方法。 通过使用涂覆有含有 = 20重量%ZrO 2的Y 2 O 3的覆盖层或相当体积量的其它难熔氧化物(例如Al 2 O 3或其组合)的平均厚度为≥10μm的石墨盘, 再生料和重涂剂之间的托盘寿命可以大大延长。
Abstract:
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.
Abstract:
According to the present invention there is provided a method of making a finegrained tungsten carbide—cobalt cemented carbide comprising mixing, milling according to standard practice followed by sintering. By introducing nitrogen at a pressure of more than 0.5 atm into the sintering atmosphere after dewaxing but before pore closure a grain refinement including reduced grain size and less abnormal grains can be obtained.
Abstract:
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.
Abstract:
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.
Abstract:
A coated turning insert particularly useful for turning in stainless steel is disclosed. The insert is characterized by a WC—Co-based cemented carbide substrate having a highly W-alloyed Co-binder phase and a coating including an inner layer of TiCxNyOz with columnar grains followed by a layer of fine-grained &kgr;-Al2O3 and a top layer of TiN. The layers are deposited by using CVD-methods.
Abstract:
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.
Abstract:
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.