| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a binderless ultrafine particle cemented carbide of a WC-MC phase which is alternative to and has same heat expansion coefficient as a cemented carbide formed by using conventional a WC and TiC-WC solid solution composite carbide phase, for improving lens molding accuracy in molding die for aspherical glass lens.SOLUTION: A V addition amount is set to be 30 mass% to 100 mass% based on Ni and a C addition amount is set to be over 300 mass% and 1250 mass% or less based on Ni in a cemented carbide containing tungsten carbide (WC) as a main component and having a Ni amount of 0.12 mass% to 0.3 mass% as a main component. As a result, a MC phase (M:symbol representing metal element) containing W, V, Cr and Ni is dispersed in an alloy structure, so that a transverse rupture strength of 2100 MPa or more and heat expansion coefficient (RT-600°C) of 4.8MKto 5.1MKcan be achieved. Same property is obtained by replacing a part or all of Ni with Co.</p> |
