Bethlehem Steel Corporation

Johnson Shipman

Herbert L Gilles

Breakouts due to insufficient skin thickness exiting below caster mold are prevented. Minimum mold heat removal rate is defined in terms of casting speed, mold faces, mold size, material grade and tundish superheat, then calculated, indicated and compared to actual measured values of heat removal rate. As a result of the comparison, caster preset speed correction is taken to automatically maintain the mold heat removal rate above the minimum level where breakouts occur.

Method and apparatus for controlling caster heat removal by varying

Strand surface temperature is measured accurately at multiple stations in spray cooling region of a continuous metal caster where environmental conditions are severe. Each station includes a pyrometer having a light pipe with a tip aimed at the strand and provided with both air and water wash streams. Control devices, operating in response to sequence timers, periodically resets measuring circuits, interrupts each strand cooling spray and light pipe wash water stream, and turns on the air wash stream, all during a short temperature sampling period. Selection of sampling period is governed by light pipe location, pyrometer response time, and strand reheat properties when spray is off. The peak temperature measured at each station is stored as the true strand temperature for that location. Thereafter strand and light pipe cooling are restored while the air wash is interrupted. Stored temperature signals may be recorded and analyzed to define caster operating parameters and cooling practices.

Method and apparatus for measuring product surface temperature in a

Heat removal in a continuous metal casting machine may now be gauged by new normalized thermal parameters instead of the conventional coolant temperature differential parameter. One new thermal parameter is caster mold heat removal rate per unit length of peripheral mold face. This enables a direct comparison of mold sizes and designs. A second new parameter is mold face specific heat removal as a function of the first new parameter and casting speed. The second new parameter is indicative of strand skin growth without actually measuring skin thickness. Third and fourth new parameters are derived by independently ratioing the first and second new parameters so as to reference to a base mold face with the other mold faces. All of the new thermal parameters may also be used to gauge heat removal from caster spray cooling and roll cooling zones. Instrumentation is provided for computing the new thermal parameters during caster operation.

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Bethlehem, PA, United States of America

Johnson Shipman