Die-casting sleeve and its production method

Abstract

A die-casting sleeve comprising an outer cylinder made of a low-thermal-expansion metal material, and an inner cylinder shrink-fit into the outer cylinder; an outer peripheral surface of the outer cylinder being provided with a flange for fixing the die-casting sleeve to a stationary die block of a die-casting machine; the inner cylinder being constituted by a front member of a low-thermal-expansion metal material arranged on the injection opening side, and a rear member of silicon-nitride-based ceramics arranged in close contact with a rear end surface of the front member; the outer cylinder having an average thermal expansion coefficient αof 1×10/° C. to 5×10/° C. between 20° C. and 200° C.; the front member having an average thermal expansion coefficient αof 1×10/° C. to 5×10/° C. between 20° C. and 200° C.; the difference between αand αbeing −1×10/° C. to 1×10/° C.; and the axial length L(mm) and inner diameter D(mm) of the front member, and the distance L(mm) from a tip end of the outer cylinder to a rear end of the flange meeting ⅓×D≤L≤L+20.