Hitachi Metals, Ltd.

Toshio Okitsu

Kiyoshi Furushima

Yoshikazu Sano

Itsuo Korenaga

Shingo Nogami

Toshinori Yashiro

Michio Haga

Die casting cylinder

A compound roll for rollng composed of a shell made of high-chromium cast iron and a core made of cast or forged steel. The shell has a large residual compressive stress. The high-chromium cast iron shell has a composition by weight of 2.0-3.5% C, 0.5-1.5% Si, 0.4-1.5% Mn, 8-25% Cr, 0.5-3.0% Mo, 1.5% or less Ni and the balance being essentially Fe for hot rolling, and 2.5-3.5% C, 0.5-1.5% Si, 0.4-1.5% Mn, 0.5-3.0% Ni, 8-25% Cr, 1.0-5.0% Mo and the balance being essentially Fe for cold rolling. The shell's Shore hardness is 70 or more for hot rolling and 90 or more for cold rolling, and the core's tensile strength and elongation are 55 kg/mm.sup.2 or more and 1.0% or more, respectively. The residual compressive stress of the shell is 20 kg/mm.sup.2 or more and serves to prevent cracks from penetrating into the depths of the shell, thereby preventing spalling effectively. This compound roll can be manufactured by a shell casting method.

High-chromium compound roll

Growing community of inventors

Kitakyusyu, Japan

Toshio Okitsu