Patent ID: 6309482
Filing Date: 2001-10-30
Classification: B21B,C21D

Abstract:
In a steel rolling mill, the in-line combination of(a) a Steckel mill for reversingly rolling a steel product above T.sub.nr to an interim reduced thickness and to obtain a controlled austenite recrystallization of the steel microstructure, and between T.sub.nr and Ar.sub.3 to a target end-product thickness and to pancake the austentite microstructure, the Steckel mill having associated upstream and downstream coiler furnaces for coiling steel product of a suitable thickness and maintaining the temperature of the steel product above T.sub.nr to obtain a controlled recrystallization of the steel;(b) a flying shear in the vicinity of the Steckel mill, for severing the leading edge of the steel product; and for steel product having a weight exceeding the capacity of a limiting apparatus in the combination, also for severing the steel product into a target portion having a weight within the capacity of the limiting apparatus, and a surplus portion; and(c) a controlled cooling apparatus downstream of the Steckel mill and the shear, the controlled cooling apparatus being operational to, in a single pass of the steel product therethrough following the rolling in the Steckel mill, reduce the temperature of the steel product from an entry temperature of about the Ar.sub.3 to an exit temperature of at least about 200.degree. C. lower than the Ar.sub.3, at a cooling rate of about 12.degree. C. to about 20.degree. C. per second, in order to obtain a product having a relatively large amount of bainite and being relatively free of marsenite.