Soft magnetic alloy and method for producing soft magnetic alloy
View Patent ↗A soft magnetic alloy is provided that consists essentially of 47 weight percent≤Co≤50 weight percent, 1 weight percent≤V≤3 weight percent, 0 weight percent≤Ni≤0.2 weight percent, 0.08 weight percent≤Nb≤0.12 weight percent, 0 weight percent≤C≤0.005 weight percent, 0 weight percent≤Mn≤0.1 weight percent, 0 weight percent≤Si≤0.1 weight percent, remainder Fe.
1. A soft magnetic alloy consisting of 47 weight percent≤Co≤50 weight percent, 1 weight percent≤V≤3 weight percent, 0 weight percent≤Ni≤0.2 weight percent, 0.08 weight percent≤Nb≤0.12 weight percent, 0 weight percent≤C≤0.007 weight percent, 0 weight percent≤Mn≤0.1 weight percent, 0 weight percent≤Si≤0.1 weight percent, up to 0.5 weight percent impurities selected from the group consisting of one or more of Cr, Cu, Mo, Al, S, Ti, Ce, B, N, Mg, Ca, P and mixtures thereof, remainder Fe,
wherein the soft magnetic alloy has a yield strength (0.2% strain) of between 200 MPa and 450 MPa in an annealed state,
wherein the soft magnetic alloy has a resistivity of at least 0.4 μΩm, or an induction B(8 A/cm) of at least 2.12 T, or both, and
wherein in an annealed state, the soft magnetic alloy comprises a yield strength (0.2% strain) that lies within ±10% of a linear function of yield strength (0.2% strain) against annealing temperature at a given annealing time over an annealing temperature range of 730° C. to 900° C.
2. The soft magnetic alloy according to claim 1 , wherein the alloy has a nickel content such that 0 weight percent<Ni≤0.2 weight percent.
3. The soft magnetic alloy according to claim 1 , wherein the alloy has a manganese content such that 0 weight percent<Mn≤0.07 weight percent.
4. The soft magnetic alloy according to claim 1 , wherein the alloy has a silicon content of 0 weight percent<Si≤0.07 weight percent.
5. The soft magnetic alloy according to claim 1 , wherein the soft magnetic alloy has a yield strength (0.2% strain) that is a linear function of annealing temperature over an annealing temperature range of 740° C. to 865° C.
6. The soft magnetic alloy according to claim 1 , wherein the soft magnetic alloy has a resistivity of at least 0.4 μΩm.
7. The soft magnetic alloy according to claim 1 , wherein the soft magnetic alloy has an induction B(8 A/cm) of at least 2.12 T.
8. The soft magnetic alloy according to claim 1 , wherein the soft magnetic alloy has an induction B(8 A/cm) of at least 2.12 T and a yield strength of at least 370 MPa.
9. The soft magnetic alloy according to claim 1 , wherein after annealing at a temperature in the range of 720° C. to 900° C., the soft magnetic alloy has a yield strength in the range of 200 MPa and 450 MPa, and a power loss density at 2 T and 400 Hz of less than 90 W/kg.
10. The soft magnetic alloy according to claim 1 , wherein the yield strength of the soft magnetic alloy is adjustable over a range of at least 130 MPa after having been annealed at 750° C. or at 871° C.
11. A stator for an electric motor, comprising the soft magnetic alloy according to claim 1 .
12. A rotor for an electric motor, comprising the soft magnetic alloy according to claim 1 .
13. An electric motor comprising a stator and rotor, each comprising a soft magnetic alloy according to claim 1 .
14. A method for manufacturing a rotor for an electric motor comprising providing the soft magnetic alloy according to claim 1 and annealing at a temperature of 730 to 790° C.
15. A method for manufacturing a stator for an electric motor comprising providing the soft magnetic alloy according to claim 1 and annealing at a temperature of 800° C. to 880° C.
16. The soft magnetic alloy according to claim 1 , wherein the alloy has a carbon content such that 0 weight percent≤C<0.005 weight percent.
17. The soft magnetic alloy according to claim 1 , wherein the alloy has a carbon content such that 0 weight percent<C≤0.005 weight percent.
18. The soft magnetic alloy according to claim 17 , wherein the alloy has a carbon content such that 0 weight percent<C<0.003 weight percent.
19. The soft magnetic alloy according to claim 1 , wherein oxygen is present as an impurity in an amount up to 0.009 weight percent.
20. A method for manufacturing a soft magnetic alloy, comprising providing a melt consisting of 47 weight percent≤Co≤50 weight percent, 1 weight percent≤V≤3 weight percent, 0 weight percent≤Ni≤0.2 weight percent, 0.08 weight percent≤Nb≤0.12 weight percent, 0 weight percent≤C≤0.007 weight percent, 0 weight percent≤Mn≤0.1 weight percent, 0 weight percent≤Si≤0.1 weight percent, up to 0.5 weight percent impurities selected from the group consisting of one or more of Cr, Cu, Mo, Al, S, Ti, Ce, B, N, Mg, Ca, P and mixtures thereof, remainder Fe;
cooling and solidifying the melt and forming a blank;
hot rolling the blank followed by
cold rolling the blank, and subsequently
annealing at least a portion of the blank at a temperature in the range of 730° C. to 880° C. for a time sufficient to obtain a soft magnetic alloy having a yield strength (0.2% strain) of between 200 MPa and 450 MPa in an annealed state, either a resistivity of at least 0.4 μΩm, or an induction B(8 A/cm) of at least 2.12 T, or both, and wherein in an annealed state, the soft magnetic alloy comprises a yield strength (0.2% strain) that lies within ±10% of a linear function of yield strength (0.2% strain) against annealing temperature at a given annealing time over an annealing temperature range of 730° C. to 900° C.
21. The method according to claim 20 , wherein at least a portion of the blank is annealed at a temperature in the range of 740° C. to 865° C.
22. The method according to claim 20 , wherein at least a portion of the blank is annealed at a temperature in the range of 730° C. to 790° C. or in the range of 800° C. to 880° C.
23. The method according to claim 20 , wherein the hot rolling of the blank produces a thickness reduction in the blank of 90%.
24. The method according to claim 20 , wherein the hot rolling of the blank includes rolling at a temperature in the range of 1100° C. to 1300° C.
25. The method according to claim 20 , further comprising, after hot rolling, cooling the blank to a temperature of above 730° C. and then quenching to room temperature, or cooling the blank and reheating to a temperature above 730° C., and then quenching to room temperature.
26. The method according to claim 20 , further comprising pickling the blank before cold rolling.
27. The method according to claim 20 , wherein the cold rolling of the blank produces a thickness reduction in the blank of 90%.
28. The method according to claim 20 , wherein after cold rolling, the blank has a thickness in the range of 0.3 mm to 0.4 mm.
29. A method for manufacturing a semi-finished part comprising forming a blank according to the method according to claim 20 and separating a portion of the blank to produce a semi-finished part.
30. The method according to claim 29 , further comprising assembling a plurality of semi-finished parts manufactured by the method according to claim 28 and forming a laminated soft magnetic article.