METHOD FOR MANUFACTURING A STRIP HAVING A VARIABLE THICKNESS AND ASSOCIATED STRIP

摘要

A method for manufacturing a strip having a variable thickness along its length, comprising the steps:
an initial strip of constant thickness is provided;homogeneous cold rolling of the initial strip along its length in order to obtain an intermediate strip of constant thickness along the rolling direction;flexible cold rolling of the intermediate strip along its length in order to obtain a variable thickness strip, having, along its length, first areas with a first thickness (e+s) and second areas with a second thickness (e), less than the first thickness (e+s),continuous annealing of the strip.;The plastic deformation ratio generated, after an optional intermediate recrystallization annealing, by the homogeneous cold rolling and the flexible cold rolling steps in the first areas is greater than or equal to 30%.

主权项

1. A method for manufacturing a strip having a variable thickness along its length, made of an iron-based alloy, the strip being made of an alloy comprising by weight:
34.5%≦Ni≦53.5% 0.15%≦Mn≦1.5% 0≦Si≦0.35% 0≦C≦0.07% optionally: 0≦Co≦20% 0≦Ti≦0.5% 0.01%≦Cr≦0.5% the remainder being iron and impurities necessarily resulting from the elaboration, the method successively comprising the following steps: providing an initial strip of constant thickness (E0), obtained by hot rolling; homogeneous cold rolling of the initial strip along its length in order to obtain an intermediate strip of constant thickness (Ec) along the rolling direction; flexible cold rolling of the intermediate strip along its length in order to obtain a strip of variable thickness along the rolling direction, the variable thickness strip having along its length, first areas having a first thickness (e+s) and second areas (10) having a second thickness (e), smaller than the first thickness (e+s), continuous final annealing of the variable thickness strip in a final annealing oven, wherein the plastic deformation ratio generated, after an optional intermediate recrystallization annealing, by the steps of homogeneous cold rolling and of flexible cold rolling in the first areas of the variable thickness strip is greater than or equal to 30% and in which the difference (Δτ) between the plastic deformation ratio (τ2) generated, after an optional intermediate recrystallization annealing, by the steps of homogeneous cold rolling and of flexible cold rolling in the second areas and the plastic deformation ratio generated, after an optional intermediate recrystallization annealing, by the steps of homogeneous cold rolling and of flexible cold rolling in the first areas of the variable thickness strip is smaller than or equal to 13% if the thickness (E0) of the initial strip is strictly greater than 2 mm and smaller than or equal to 10% if the thickness (E0) of the initial strip is smaller than or equal to 2 mm.