Electrical steel processing without a post cold-rolling intermediate anneal

Patent metadata

Field	Value
Publication number	US-11220720-B2
Application number	US-201916362332-A
Country	US
Kind code	B2
Filing date	Mar 22, 2019
Priority date	Jan 12, 2012
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

Embodiments of the present invention comprise; annealing steel sheets (e.g., hot rolled steel sheets or thin cast strip steel); cold rolling the sheets in one or more cold rolling steps (e.g., with annealing steps between multiple cold rolling steps); and performing one or more of tension leveling, a rough rolling, or a coating process on the sheets after cold rolling, without an intermediate annealing step between the final cold rolling step and the tension leveling, the rough rolling, or the coating process, or the customer stamping or final customer annealing. In order to achieve the desired properties for the steel sheet, stamping and final annealing is performed by the customer. The new process provides an electrical steel with the similar, same, or better magnetic properties than an electrical steel manufactured using the traditional processing that utilizes an intermediate annealing step after cold rolling and before the stamping and final annealing.

First claim

What is claimed is:

1. A stamped part formed from a motor lam electrical steel, comprising:
the motor lam electrical steel comprising:
silicon (Si) in a range of 2.2-3.5% weight;
aluminum (Al) in a range of 0.15-1% weight;
manganese (Mn) in a range of 0.005-1% weight;
carbon (C) less than or equal to 0.04% weight; and
antimony (Sb) or Tin (Sn) less than or equal to 0.1% weight;
wherein a remainder comprises unavoidable impurities and iron;

wherein the motor lam electrical steel is produced by:
hot rolling steel in one or more hot rolling passes into a steel sheet to a post hot rolling thickness of less than 0.1 inches;
annealing the steel sheet in a first anneal after hot rolling, wherein the annealing after the hot rolling is a post hot rolling batch anneal, and wherein the annealing after the hot rolling is performed at a post hot rolling annealing temperature that is greater than or equal to 1550 degrees Fahrenheit;
cold rolling the steel sheet in one or more first cold rolling passes after the first anneal to a post first cold rolling thickness less than 0.05 inches;
annealing the steel sheet in a second anneal after the one or more first cold rolling passes, wherein the annealing in the second anneal after the one or more first cold rolling passes is a post first cold rolling batch anneal, and wherein the annealing in the second anneal after the one or more first cold rolling passes is performed at a post first cold rolling annealing temperature that is greater than or equal to 1550 degrees Fahrenheit;
cold rolling the steel sheet in one or more final cold rolling passes after the second anneal to a post cold rolling thickness of less than 0.015 inches to form the motor lam electrical steel; and
wherein the motor lam electrical steel is stamped into the stamped part and thereafter final annealed without an intermediate anneal after the one or more final cold rolling passes, and before the stamping and the final annealing, and wherein the final annealing after stamping is performed at a post stamping annealing temperature that is greater than or equal to 1550 degrees Fahrenheit; and
wherein the stamped part has a permeability greater than or equal to 4500 G/Oe and a core loss less than or equal to 70 W/kg when tested at 1.0 T at 1000 Hz after the annealing after the stamping in all directions in the stamped part.

2. The stamped part formed from the motor lam electrical steel of claim 1 , wherein the stamped part has a surface roughness less than or equal to 15 microns.

3. The stamped part formed from the motor lam electrical steel of claim 1 , wherein the motor lam electrical steel comprises:
silicon (Si) is in the range of 2.8-3.5% weight;
manganese (Mn) in the range of 0.2-0.4% weight; and
aluminum (Al) in the range of 0.5-0.75% weight.

4. The stamped part formed from the motor lam electrical steel of claim 1 , wherein the motor lam electrical steel is further produced by sending the motor lam electrical steel to a customer for the stamping into the stamped part and the final annealing after the stamping.

5. The stamped part formed from the motor lam electrical steel of claim 1 , wherein the post hot rolling annealing temperature is greater than or equal to 1600 degrees F., and the post first cold rolling annealing temperature is greater than or equal to 1600 degrees F.

6. The stamped part formed from the motor lam electrical steel of claim 1 , wherein the permeability is greater than or equal to 6000 G/Oe and the core loss is less than or equal to 20.0 W/kg when tested at 1.0 T at 400 Hz after the annealing after the stamping in all directions of the stamped part.

7. The stamped part formed from the motor lam electrical steel of claim 6 , wherein the permeability is greater than or equal to 7500 G/Oe and the core loss is less than or equal to 16.0 W/kg when tested at 1.0 T at 400 Hz after the annealing after the stamping in all directions of the stamped part.

8. A stamped part formed from a motor lam electrical steel, comprising:
the motor lam electrical steel comprising:
silicon (Si) in a range of 2.2-3.5% weight;
aluminum (Al) in a range of 0.15-1% weight;
manganese (Mn) in a range of 0.005-1% weight;
carbon (C) less than or equal to 0.04% weight; and
antimony (Sb) or Tin (Sn) less than or equal to 0.1% weight;
wherein a remainder comprises unavoidable impurities and iron;

wherein the motor lam electrical steel is produced by:
procuring a steel, wherein a thickness of the steel is less than or equal to 0.1 inches;
annealing the steel, wherein the annealing is a batch annealing, and wherein the annealing is performed at an annealing temperature that is greater than or equal to 1550 degrees Fahrenheit;
cold rolling the steel in one or more cold rolling passes after the annealing into a steel sheet with a post cold rolling thickness less than 0.015 inches to form the motor lam electrical steel;

wherein the motor lam electrical steel is stamped into the stamped part and thereafter final annealed without an intermediate anneal after the one or more cold rolling passes, and before the stamping and the final annealing, and wherein the final annealing after the stamping is performed at a post stamping annealing temperature that is greater than or equal to 1550 degrees Fahrenheit; and
wherein the stamped part has a permeability greater than or equal to 4500 G/Oe and a core loss less than or equal to 70 W/kg when tested at 1.0 T at 1000 Hz after the annealing after the stamping in all directions in the stamped part.

9. The stamped part formed from the motor lam electrical steel of claim 8 , wherein the stamped part has a surface roughness less than or equal to 15 microns.

10. The stamped part formed from the motor lam electrical steel of claim 8 , wherein the electrical steel comprises:
silicon (Si) is in the range of 2.8-3.5% weight;
manganese (Mn) in the range of 0.2-0.4% weight; and
aluminum (Al) in the range of 0.5-0.75% weight.

11. The stamped part formed from the motor lam electrical steel of claim 8 , wherein the motor lam electrical steel is further produced by sending the steel sheet to a customer for the stamping and the final annealing after the stamping.

12. The stamped part formed from the motor lam electrical steel of claim 8 , wherein the annealing temperature is greater than or equal to 1600 degrees F., and the post stamping annealing temperature is greater than or equal to 1600 degrees F.

13. The stamped part formed from the motor lam electrical steel of claim 8 , wherein the permeability is greater than or equal to 6000 G/Oe and the core loss is less than or equal to 20.0 W/kg when tested at 1.0 T at 400 Hz after the annealing after the stamping in all directions in the stamped part.

14. The stamped part formed from the motor lam electrical steel of claim 13 , wherein the permeability is greater than or equal to 7500 G/Oe and the core loss is less than or equal to 16.0 W/kg when tested at 1.0 T at 400 Hz after the annealing after the stamping in all directions of the stamped part.

15. A method of manufacturing a stamped part formed from a motor lam electrical steel, comprising:
hot rolling steel into a steel sheet in one or more hot rolling passes to a post hot rolling thickness of less than 0.1 inches;
annealing the steel sheet in a first anneal after hot rolling, wherein the annealing after the hot rolling is a post hot rolling batch annealing, and wherein the annealing after the hot rolling is performed at a post hot rolling annealing temperature that is greater than or equal to 1550 degrees Fahrenheit;
cold rolling the steel sheet in one or more fi

Assignees

• Nucor Corp

Inventors

• Hill Theodore E
• Gallo Eric E

Classifications

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title

• H01F1/16

  in the form of sheets (H01F1/147 takes precedence) · CPC title

• C21D8/1261

  following hot rolling · CPC title

• C22C38/004

  Very low carbon steels, i.e. having a carbon content of less than 0,01% · CPC title

• C22C38/02

  containing silicon · CPC title