SUPER HARD ABRASIVE GRAIN GRINDSTONE FOR HIGH SPEED GRINDING

摘要

PURPOSE:To reduce the specific gravity to reduce the centrifugal force in the case of rotating a grindstone at high speed and to increase safety by using a porous silicon nitride ceramic for a grindstone main body. CONSTITUTION:A grindstone main body is formed of silicon nitride ceramics whose apparent porosity is 15-25%, whose flexural strength is =10kgf/mm2 at a room temperature and whose thermal expansion coefficient is (2.5-3.5)X10-6/ deg.C at a room temp.-1000 deg.C. A multiporous type grinding layer consisting of the super hard abrasive grain of a cubic boron nitride or diamond, etc., and a vitrified binder is then provided on the outer peripheral surface of this grindstone main body and a desired super hard abrasive grain grindstone for a high speed grinding is obtained.