Hoogovens Groep B.v.

Centre De Recherches Metallurgiques-centrum Voor Research in De

Cockerill Sambre S.a.

N.v. Sidmar

Erik B Van Perlstein

Huibert W Den Hartog

Stephan H Wilmotte

Michel Dubois

Robert F Gadellaa

Huibert Den Hartog

Simon Vandenbruaene

Michel Beguin

A method and apparatus for continuously treating a strip of hot dip-galvanized steel. The method comprises the steps of rapidly reheating the strip to a predetermined temperature between 460.degree. C. and 600.degree. C., with a heating flux greater than 180 kWatts per meter squared based for each face of the strip; maintaining the strip at a substantially constant temperature for a predetermined period of time lasting between 10 and 30 seconds; and subsequently cooling the strip rapidly to a temperature below 420.degree. C., using a cooling flux of a magnitude greater than 100 kWatts per meter squared for each face of the strip. The step of rapidly reheating is performed following a drying operation conducted on the strip as it exits from a zinc bath. The apparatus comprises various elements for performing the method, as well as a vessel containing the zinc bath, redirecting rolls which define an upward and substantially vertical trajectory for the strip and a drying mechanism disposed along the trajectory downstream of the vessel's exit. Preferably, the rapidly heating of the strip is accomplished using an induction furnace operating at a frequency between 100 and 500 kHz, and the rapid cooling is provided by nozzles which, in turn, deliver a mist or fine spray of water and air.

Method and apparatus for continuous treatment of a strip of hot dip

In the manufacture of formable steel in the form of a strip with a final thickness of between 0.5 and 1.5 mm, in a number of continuous successive process stages, molten steel is continuously cast into a slab of less than 100 mm thickness and the slab is rolled into the strip. To simplify the apparatus required, and improve process control, the slab is cooled down to a rolling temperature of between 300.degree. C. and a temperature T.sub.t at which at least 75% of the material is converted into ferrite, and the rolling of the slab into strip comprises at least one reduction stage with a thickness reduction of over 30%. The rolling exit speed is less than 1000 m/min. After recrystallization, the strip is coiled.

Method for the manufacture of formable steel

In the manufacture of formable steel strip having a thickness between 0.5 and 1.5 mm, the following process steps are performed sequentially in a continuous process:

Method and apparatus for the manufacture of formable steel strip

A non-ageing low-alloy hot-rolled strip-form formable steel has a carbon content of between 0.02 and 0.10 wt. % and a thickness of between 0.5 and 5.0 mm. In order to bind N so as to achieve a non-ageing steel, while permitting direct entry of the steel to rolling from casting, the contents of titanium, nitrogen and sulphur in wt. % satisfy the conditions:

Non-ageing low-alloy hot-rolled strip-form formable steel

Method for the manufacture of formable steel strip

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Beverwijk, Netherlands

Erik B Van Perlstein