Method of making a cemented carbide powder with low sintering shrinkage and the powder obtained

Abstract

A method of making cemented carbide powder with low sintering shrinkage including WC and 4-15 wt-% Co and up to 20 wt-% cubic carbide forming elements from the Groups 4 and 5 of the Periodic Table of the Elements by the powder metallurgical techniques wet milling, pressing and sintering. According to the method wet milling is performed in a rotating ball mill with a ratio between the weight of milling bodies and powder of 2-5. The milling bodies are shaped either as spheres or cylinders with semi-spherical end surfaces. The spherical bodies have a diameter of 10 to 15 mm and the cylindrical bodies have a diameter and height of 10 to 15 mm. The composition of the milling bodies is WC with 6 to 10 wt-% Co. A powder made according to the method is described.

1 . Method of making cemented carbide powder with low sintering shrinkage comprising WC and 4-15 wt-% Co and up to 20 wt-% cubic carbide forming elements from the Groups 4b and 5b of the Periodic Table of the Elements by means of the powder metallurgical techniques wet milling, pressing and sintering characterised in wet milling in a rotating ball mill with a ratio between the weight of milling bodies and powder of 2-5, the milling bodies being shaped either as spheres or cylinders with semi-spherical end surfaces whereby the spherical bodies have a diameter of 10 to 15 mm and the cylindrical bodies have a diameter and height of 10 to 15 mm and with a composition of the milling bodies of WC with 6 to 10 wt-% Co. 
     
     
         2 . Cemented carbide powder with low sintering shrinkage comprising WC and 4-15 wt-% Co and up to 20 wt-% cubic carbide forming elements from the Groups 4b and 5b of the Periodic Table of the Elements with WC-grains with an average grain size in the range 3-9 μm characterised in that the powder has a sintering shrinkage of 16.5 to 17.5%, preferably of 16.7 to 17.3% at a compacting pressure of 123 MPa.