| 摘要 |
PROBLEM TO BE SOLVED: To prevent a tip of an inner cylinder from being projected while in use by interposing a friction reducing material between an outer cylinder of a sleeve and the inner cylinder of the sleeve. SOLUTION: An inner cylinder 2 made of ceramics material is shrink fitted into a metallic outer cylinder 1 of a sleeve to make the sleeve for die casting. Boron nitride of <=10μm in mean grain size and <=100μm in thickness is interposed between the outer cylinder 1 and the inner cylinder 2 to reduce the friction. The residual stress in shrink fit can be reduced. The metallic material of the outer sleeve 1 is 1-5*10<-6> / deg.C in the mean coefficient of thermal expansion at 20-300 deg.C, and >=5*10<-6> / deg.C at 20-600 deg.C. The metallic material is preferably the metal in which the precipitated reinforcing element is added to Fe-Ni-Co alloy. The ceramics material is preferably the silicon nitride or silicon nitride sintered body. The inner cylinder 2 is pressed in the axial direction through fixed rings 3, 4, and held. The service life of the inner cylinder 2 is improved, the number of exchange is reduced, and the productivity is improved. |
