Steel material for soft magnetic part, soft magnetic part, and method for producing soft magnetic part

Patent metadata

Field	Value
Publication number	US-11248283-B2
Application number	US-201716463172-A
Country	US
Kind code	B2
Filing date	Dec 7, 2017
Priority date	Dec 8, 2016
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

The steel material for a soft magnetic part according to the present invention has a chemical composition consisting of, in mass %, C: 0.02 to 0.13%, Si: 0.005 to 0.50%, Mn: 0.10 to 0.70%, P: 0.035% or less, S: 0.050% or less, Al: 0.005 to 1.300%, V: 0.02 to 0.50%, and N: 0.003 to 0.030%, with the balance being Fe and impurities. The average grain diameter of ferrite grains in the steel material for a soft magnetic part ranges from 5 to 200 μm. Further, in the ferrite grains, the number Sv (number/mm2) of precipitates having a circle-equivalent diameter of 30 nm or more satisfies Formula (1):Sv≤10V×7.0×106  (1)where the V content (mass %) in the steel material for a soft magnetic part is substituted into V in Formula (1).

First claim

The invention claimed is:

1. A steel material for a soft magnetic part having a chemical composition consisting of, in mass %,
C: 0.03 to 0.13%,
Si: 0.005 to 0.50%,
Mn: 0.10 to 0.70%,
P: 0.035% or less,
S: 0.050% or less,
Al: 0.005 to 1.300%,
V: 0.02 to 0.50%,
N: 0.003 to 0.030%,
Cr: 0 to less than 0.80%,
Ti: 0 to 0.20%,
Nb: 0 to 0.20%,
B: 0 to 0.005%, and
Ca: 0 to 0.005%, with the balance being Fe and impurities, wherein
an average grain diameter of ferrite grains in the steel material for a soft magnetic part ranges from 5 to 200 μm, and
in the ferrite grains, the number Sv number/mm 2 of precipitates having a circle-equivalent diameter of 30 nm or more satisfies Formula (1):
Sv ≤10V×7.0×10 6   (1)

where a V content in mass % in the steel material for a soft magnetic part is substituted into V in Formula (1).

2. The steel material for a soft magnetic part according to claim 1 ,
wherein the chemical composition contains Cr: 0.02 to less than 0.80%.

3. The steel material for a soft magnetic part according to claim 2 ,
wherein the chemical composition contains one or more selected from a group consisting of
Ti: 0.01 to 0.20%,
Nb: 0.01 to 0.20%, and
B: 0.0008 to 0.005%.

4. The steel material for a soft magnetic part according to claim 3 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

5. The steel material for a soft magnetic part according to claim 2 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

6. The steel material for a soft magnetic part according to claim 1 ,
wherein the chemical composition contains one or more selected from a group consisting of
Ti: 0.01 to 0.20%,
Nb: 0.01 to 0.20%, and
B: 0.0008 to 0.005%.

7. The steel material for a soft magnetic part according to claim 6 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

8. The steel material for a soft magnetic part according to claim 1 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

9. A soft magnetic part having a chemical composition consisting of, in mass %,
C: 0.03 to 0.13%,
Si: 0.005 to 0.50%,
Mn: 0.10 to 0.70%,
P: 0.035% or less,
S: 0.050% or less,
Al: 0.005 to 1.300%,
V: 0.02 to 0.50%,
N: 0.003 to 0.030%,
Cr: 0 to less than 0.80%,
Ti: 0 to 0.20%,
Nb: 0 to 0.20%,
B: 0 to 0.005%, and
Ca: 0 to 0.005%, with the balance being Fe and impurities, wherein
in ferrite grains in the soft magnetic part, the number Sv number/mm 2 of precipitates having a circle-equivalent diameter of 30 nm or more satisfies Formula (1), and
maximum magnetic permeability is 0.0015 N/A 2 or more:
Sv ≤10V×7.0×10 6   (1)

where a V content in mass % in the soft magnetic part is substituted into V in Formula (1).

10. The soft magnetic part according to claim 9 ,
wherein the chemical composition contains Cr: 0.02 to less than 0.80%.

11. The soft magnetic part according to claim 10 ,
wherein the chemical composition contains one or more selected from a group consisting of
Ti: 0.01 to 0.20%,
Nb: 0.01 to 0.20%, and
B: 0.0008 to 0.005%.

12. The soft magnetic part according to claim 11 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

13. The soft magnetic part according to claim 10 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

14. The soft magnetic part according to claim 9 ,
wherein the chemical composition contains one or more selected from a group consisting of
Ti: 0.01 to 0.20%,
Nb: 0.01 to 0.20%, and
B: 0.0008 to 0.005%.

15. The soft magnetic part according to claim 14 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

16. The soft magnetic part according to claim 9 ,
wherein the chemical composition contains Ca: 0.0005 to 0.005%.

17. A method for producing a soft magnetic part comprising the steps of:
performing cold working on the steel material for a soft magnetic part according to claim 1 to produce an intermediate material; and
performing magnetic annealing on the intermediate material.

Assignees

• Nippon Steel Corp

Inventors

• Egashira Makoto
• Sueno Hidekazu
• Matsumoto Hitoshi

Classifications

• C22C38/06

  containing aluminium · CPC title

• C21D1/04

  with simultaneous application of supersonic waves, magnetic or electric fields · CPC title

• H01F1/147

  Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)} · CPC title

• C22C38/04

  containing manganese · CPC title

• C21D6/00

  Heat treatment of ferrous alloys · CPC title