Patent Number: 6,309,482

Title: Steckel mill/on-line controlled cooling combination

Abstract: The in-line combination of a reversing rolling mill (Steckel mill) and itscoiler furnaces with accelerated controlled cooling apparatus immediatelydownstream thereof and associated method permits steel to be sequentiallyreversingly rolled to achieve an overall reduction of at least about 3:1,imparted by a first reduction while the steel is kept at a temperatureabove the T.sub.nr by the coiler furnaces so as to preserve an optimumopportunity for controlled recrystallization of the steel after eachrolling pass, and a second reduction while the temperature of the steeldrops from about the T.sub.nr to about the Ar.sub.3. The second reductionis preferably of the order of 2:1 as a result of which the steel reaches afinal plate thickness. The steel product then passes through theaccelerated controlled cooling apparatus, preferably applying laminar flowcooling at least to the upper surface of the steel passing therethrough soas to reduce the temperature of the steel from about the Ar.sub.3 to atemperature at least about 250.degree. C. to about 300.degree. C. or morebelow the Ar.sub.3 at a cooling rate of at about 12.degree. C. to about20.degree. C. and preferably about 15.degree. C. per second, thereby toachieve a preferred fine-grained predominantly bainite structure affordingenhanced strength and toughness in the final steel product.

Inventors: Dorricott; Jonathan (Davenport, IA), Frank; William R. (Bettendorf, IA)

Assignee:

International Classification:

Expiration Date: 10/32013