US 6,053,996 AGranted

Method for the manufacture of a strip of formable steel

AssigneeHoogovens Staal BV

InventorsCornelis Pronk, Huibert Willem Den Hartog, Marcus Cornelis Maria Cornelissen

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Abstract

A method for the manufacture of a strip of formable steel comprises the steps of (i) forming liquid steel by continuous casting into a slab having a thickness of not more than 100 mm, (ii) rolling the slab in the austenitic region into an intermediate slab having a thickness in the range 5 to 20 mm, (iii) cooling the intermediate slab to below the Ar.sub.3 temperature, (iv) holding the intermediate slab in an enclosure for temperature homogenisation, (v) rolling the intermediate slab into strip, with at least one rolling pass applying a thickness reduction of more than 50%, at a temperature below T.sub.t and above 200.degree. C., wherein T.sub.t is the temperature at which 75% of the steel is converted into ferrite, and (vi) coiling said strip at a temperature above 500.degree. C. Advantages of simplicity of the method and the plant required for it are obtained.

Claims7

Dependent claims

A method for the manufacture of a strip of formable steel, comprising the steps of, in the following order:

(i) by continuous casting, forming liquid steel into a slab having a thickness of not more than 100 mm,
(ii) rolling said slab, while still hot from its casting and in the austenitic region, into an intermediate slab having a thickness in the range 5 to 20 mm,
(iii) cooling said intermediate slab of step (ii) to a temperature which is below the Ar.sub.3 temperature of the steel,
(iv) holding said cooled intermediate slab in an enclosure for temperature homogenization thereof,
(v) rolling said held intermediate slab into a strip, with at least one rolling pass applying a thickness reduction of more than 50%, said held intermediate slab during rolling being at a temperature in the range from above 200.degree. C. to below a temperature T.sub.t at which 75% of the steel is converted into ferrite,
(vi) coiling said strip at a temperature above 500.degree. C.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/981,612Filed 15 Apr 1998
Priority: NL 100069429 Jun 1995
Granted: 25 Apr 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

B21B 1/463
For rolling metal immediately subsequent to continuous casting: in a continuous process, i.e. the cast not being cut before rolling
C21D 8/0426
Characterised by the working steps: hot rolling
C21D 9/0081
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor: for slabs; for billets
C21D 9/68
Furnaces for treating strips or wire: furnace coilers; Hot coilers