Hitachi Metals, Ltd.

Itsuo Korenaga

Kiyoshi Furushima

Akira Noda

Shingo Nogami

Toshio Okitsu

Toshinori Yashiro

Takuya Ohsue

Hiroshi Fukuzawa

The crack-resistant compound sleeve roll having a shell portion made of a sintered alloy and a core portion made of steel is produced by (a) charging an alloy powder consisting essentially, by weight, of 1.0-3.5% of C, 2% or less of Si, 2% or less of Mn, 10% or less of Cr, 3.0-15.0% of W, 2.0-10.0% of Mo and 1.0-15.0% of V, the balance being substantially Fe and inevitable impurities, into a metal capsule disposed around a roll core; (b) after evacuation and sealing, subjecting the alloy powder to a HIP (hot isostatic pressing) treatment at 1100.degree.-1300.degree. C. to form a shell portion; (c) after removing the metal capsule, subjecting the sintered shell portion to a heat treatment having hardening at 1140.degree.-1220.degree. C. and annealing at 540.degree.-620.degree. C.; and (d) chamfering edge portions of the roll on both axial ends thereof such that a boundary of the shell portion and the core portion exists in a chamfered surface.

Compound sleeve roll and method for producing same comprising chamfered

Die casting cylinder

Method for correcting deflection of a plastic roll under conditions of use. A drilled roll for processing thermoplastic material such as vinyl or the like is deflected during the use due to a thermal distortion to cause a thickness fluctuation in the rolled products. To extinguish this deflection, the roll is corrected by a process having the steps of heating the roll up to the operating temperature, measuring the amount and direction of the deflection of the heated roll, cooling the roll to the room temperature, mechanically imparting to the roll a deflection of the same amount and direction as those observed in the heated roll, and processing the roll by grinding the roll in the mechanically deflected state. After the processing, the roll exhibits an apparent deflection of the same amount in the opposite direction to those exhibited in the heated state, as it is relieved from the mechanical deflecting force. Then, as the roll is heated to the operating temperature before the rolling work, the roll is thermally deflected to negate the apparent deflection so that the rolling is effected by the roll surface having no apparent deflection.

Method of processing roll

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Kitakyusyu, Japan

Itsuo Korenaga