Sandvik Intellectual Property Ab

Sandvik Ab

Sandvik Intellectual Property Aktiebolag

Ove Alm

Mats G Waldenstrom

Ake Ostlund

Mats Waldenstr&ouml;m

Susanne Norgren

Alistair Grearson

&angst;ke &Ouml;stlund

Ake &Ouml;stlund

There is disclosed a method of making a ready to press cemented carbide powder with low compaction pressure suitable for the production of submicron cemented carbide by means of powder metallurgical techniques milling, pressing and sintering. The method comprises using from about 1 to about 3 wt-% pressing agent with the following composition, less than about 90 wt-% PEG and from about 10 to about 75 wt-% of blends of high molecular (C12-&#x3c;C20) saturated or unsaturated fatty acids, or salts thereof containing at least one element of Al, Ba, Ca, Co, Cr, Mg, N, Na, V, Zn. Preferably the grain size of the cemented carbide powder is submicron. In a preferred embodiment the method includes a dry pre-milling of the hard constituents mainly WC-powder for about 2-45 hours in ball mills with cemented carbide milling bodies or using other suitable dry milling techniques prior to a wet milling step. The invention also relates to the powder obtained by the method.

Method of making a submicron cemented carbide powder mixture with low compacting pressure and the resulting powder

As there is disclosed a cemented carbide body comprising WC with an average grain size of &#x3c;10 &#x3bc;m in a binder phase. In the cemented carbide body the WC grains can be classified in at least two groups in which a group of smaller grains has a maximum grain size aand a group of larger grains has a minimum grain size band each group contains at least 10 % of the total amount of WC grains. According to the invention b&#x2212;a&#x3e;0.5 &#x3bc;m and the difference in grain size within each group is &#x3e;1 &#x3bc;m.

Cemented carbide body with increased wear resistance

There is disclosed a cemented carbide insert with excellent properties for machining of steels and stainless steels. The cemented carbide comprises WC and 4-25% Co. The WC-grains have an average grain size in the range 0.2-3.5 &#x3bc;m and a narrow grain size distribution in the range 0-4.5 &#x3bc;m. According to the method of the invention a cemented carbide cutting tool insert is made by mixing powders of WC, TiC, TaC and/or NbC, binder metal and pressing agent, drying preferably by spray drying, pressing to inserts and sintering. The method characterised in

Cemented carbide insert for turning, milling and drilling

As there is disclosed a cemented carbide body comprising WC with an average grain size of <10 &mgr;m in a binder phase. In the cemented carbide body the WC grains can be classified in at least two groups in which a group of smaller grains has a maximum grain size a,and a group of larger grains has a minimum grain size b,and each group contains at least 10 % of the total amount of WC grains. According to the invention b,&minus;a,>0.5 &mgr;m and the difference in grain size within each group is >1 &mgr;m.

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Hägersten, Sweden

Ove Alm