Tata Steel Nederland Technology B.v.

Tata Steel Nederland Tubes Bv

Tata Steel Ijmuiden B.v.

Steven Celotto

David Neal Hanlon

Arjen Kamp

Gerardus Jacobus Paulussen

Robertus Flipsen

Basjan Berkhout

Jacques Pierre Jean Verberne

A method for manufacturing of steel tube from a long steel strip, including providing a length of steel strip material to the process, forming a tube of the steel strip material, welding the formed tube in longitudinal direction, giving the tube a heat treatment wherein the mentioned steps are performed in one continuous in-line manufacturing line and the heat treatment includes a heating regime such that in successive cross-sections of the tube a microstructure is achieved which holds at least 50 vol % austenite and a cooling trajectory to re-introduce ferrite, and/or bainite in desired volume fractions.

Method for the in-line manufacturing of steel tube

Disclosed is a process for the heat treatment of metal strip material providing mechanical properties that differ over the width of the strip, wherein the strip is heated and cooled and optionally over-aged during a continuous annealing process. At least one of the following parameters in the process differs over the width of the strip: heating rate, top temperature, top temperature holding time, cooling trajectory after top temperature; or, when over-aging is performed, at least one of the following parameters in the process differs over the width of the strip: heating rate, top temperature, top temperature holding time, cooling trajectory after top temperature, over-aging temperature, over-aging temperature holding time, lowest cooling temperature before over-aging, re-heating rate to over-aging temperature. Also, at least one of the cooling trajectories follows a non-linear temperature-time path. Also disclosed is strip material thus produced.

Process for the heat treatment of metal strip material

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Heiloo, Netherlands

Steven Celotto