Process for manufacturing a thin strip made of soft magnetic alloy and strip obtained

A continuously annealed strip in a cold rolled soft magnetic alloy, with a thickness of less than 0.6 mm, consisting of an alloy, the chemical composition of the alloy comprising by weight:

• 18% ≤ Co ≤ 55%
• 0% ≤ V + W ≤ 3%
• 0% ≤ Cr ≤ 3%
• 0% ≤ Si ≤ 3%
• 0% ≤ Nb ≤ 0.5%
• 0% ≤ B ≤ 0.05%
• 0% ≤ C ≤ 0.1%
• 0% ≤ Zr + Ta ≤ 0.5%
• 0% ≤ Ni ≤ 5%
• 0% ≤ Mn ≤ 2%
• the remainder consisting of iron and impurities resulting from elaboration,
• wherein:
• either a structure of the continuously annealed strip is partially crystallized, and such that on at least 10% of a surface of samples observed under a microscope with a magnification of ×40 after chemical etching with iron perchloride, it is not possible to identify grain boundaries;
• or a structure of the continuously annealed strip is crystallized, and such that on at least 90% of a surface area of a sample of said continuously annealed strip observed under a microscope with a magnification of ×40 after chemical etching with iron perchloride, it is possible to identify a network of grain boundaries and,
• among the grains having a surface area from 0 to 60 μm2, there exists at least one first class of grain surface area with a class width of 10 μm2 such that the first class of grain surface area of the continuously annealed strip comprises at least twice as many grains as the first class of grain surface area of a reference statically annealed cold rolled strip having the same composition as the continuously annealed strip and having a coercitive field such that a difference between the coercitive field of the reference statically annealed cold rolled strip and a coercitive field of the continuously annealed strip is less than half of the value of the coercitive field of the continuously annealed strip and,
• among the grains having a surface area from 0 to 60 μm2, there exists at least one second class of grain surface area with a class width of 10 μm2 for which a ratio of a number of grains in the second class of the continuously annealed strip to a total number of grains observed on the sample of the continuously annealed strip is greater by at least 50% than a ratio of a number of grains in the second class of the reference statically annealed cold rolled strip to a total number of grains observed on a sample of the reference statically annealed cold rolled strip,
• and wherein the continuously annealed strip has an elasticity limit Rp0.2 of at least 480 MPa.