MANUFACTURE OF IMPINGEMENT PLATE FOR USE IN CENTRIFUGAL IMPACT MILL

PURPOSE:To reduce the occurrence of cracking or nicking of a super hard chip by a method wherein the super hard chip and an impingement face part are brazed together using a silver alloy having copper held between the two sides and a super hard chip and the face part are thereafter annealed at a specific temp. CONSTITUTION:There are provided a rotor chamber 3 rotatable on the axis of a vertical shaft 15 provided in a casing 2 and impingement plates 7a spaced suitably apart and circumferentially around the chamber 3 and having super hard chips 8 detachably attached to their impingement face parts 17, whereby the materials 4 to be crushed delivered from the chamber 3 are caused to collide against the impingement plate 7a so as to be crushed. The super hard chip 8 formed into a nearly square shape with a side length of at least 15mm and a thickness of at least 8mm and the impingement face part 17 are brazed together using the silver alloy having copper held between the two sides, after which the super hard chip 8 and the impingement face part 17 are annealed at an environment temp. of 450-600 deg.C. As a result, the occurrence of cracking or nicking of the super hard chip can be reduced, thus leading to a long lifetime.