CEMENTED CARBIDE INSERT WITH BINDER PHASE ENRICHED SURFACE ZONE

摘要

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 mu m, preferably 1.3-3.0 mu m and the number of WC-grains larger than 2 times the average grain size is less than 10 grains/cm<2> measured on a representative polished section 0.5 cm<2> large, preferably less than 5 grains/cm<2>, and the number larger than 3 times the average grain size is less than 5 grains/cm<2>, preferably less than 3 grains/cm<2>. The cemented carbide is made by powder metallurgical methods and is in particular characterized in that the cooling rate, CR, from the sintring temperature, ST, exhibits the relationship 10 < CR . (ST-1300) / 1000 < 17