Sandvik Ab

Mats Waldenstr&ouml;m

Ove Alm

Mikael Lindholm

Mats Ahlgren

&angst;ke &Ouml;stlund

Leif &angst;kesson

Rolf Svensson

Ake &Ouml;stlund

The present invention relates to a method of making a cemented carbide by mixing powder of WC and possibly other powders forming hard constituents and binder phase and pressing agent, drying, pressing and sintering whereby; the mixing is wet mixing with no change in grain size or grain size distribution of the hard constituent powders; the WC grains are coated with binder metal and deagglomerated prior to the mixing. The sintering is made by microwave sintering at 1325-1410&deg; C. with a holding time of 5-15 min. As a result a cemented carbide with improved properties is obtained.

Method of making cemented carbide

The present invention relates to a coated cemented carbide insert with a binder phase enriched surface zone. The WC-grains have an average grain size in the range 1.0-3.5 &mgr;m, preferably 1.3-3.0 &mgr;m and the number of WC-grains larger than 2 times the average grain size is less than 10 grains/cm measured on a representative polished section 0.5 cm large, preferably less than 5 grains/cm , and the number larger than 3 times the average grain size is less than 5 grains/cm , preferably less than 3 grains/cm . The cemented carbide is made by powder metallurgical methods and is in particular characterized in that the cooling rate, CR, from the sintering temperature, ST, exhibits the relationship 10<CR&middot;(ST-1300)/1000<17.

Cemented carbide insert with binder phase enriched surface zone

One or more metal salts of at least one iron group metal containing organic groups are dissolved in at least one polar solvent and complex bound with at least one complex former comprising functional groups in the form of OH or NR , (R&boxH;H or alkyl). In addition, at least one insoluble, reducible salt of at least one iron group metal is suspended in the solution. Hard constituent powder and, optionally, a soluble carbon source are added to the solution. The solvent is evaporated and the powder mass is heat treated in inert and/or reducing atmosphere. As a result, a powder mixture is obtained which, after addition of a pressing agent, can be compacted and sintered according to standard practice to form a body containing hard constituents in a binder phase.

Method of making metal composite materials

The present invention relates to a method of making a cemented carbide body with a bimodal grain size distribution by powder metallurgical methods including wet mixing, without milling, of WC-powders with different grain size distributions with binder metal and pressing agent, drying, pressing and sintering. The grains of the WC-powders are classified in at least two groups, a group of smaller grains and a group of larger grains. According to the method of the present invention, the grains of the group of smaller grains are precoated with a growth inhibitor with or without binder metal.

Method of making a cemented carbide body with increased wear resistance

The present invention relates to a method of making a cemented carbide with submicron WC grain size with a powder metallurgical technique including milling, pressing and sintering. The method includes milling all components except WC for about three hours, then adding the WC powder and milling for about ten additional hours. In this way a cemented carbide powder with acceptable low compacting pressure is obtained.

Method of making a cemented carbide powder with low compacting pressure

Cemented carbide insert for turning, milling and drilling

The present invention relates to a method of making a cemented carbide comprising WC, 6-12 wt. % Co and 0.1-0.7 wt. % Cr, wherein the WC-grains are coated with Cr prior to mixing and no milling takes place during the mixing step. As a result a cemented carbide with improved properties is obtained.

Method of making a submicron cemented carbide with increased toughness

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.

Growing community of inventors

Bromma, Sweden

Mats Waldenström

Growing community of inventors

Bromma, Sweden

Mats Waldenstr&ouml;m

Mats Waldenström