Back to results
US 4,394,192 AGranted
Method for producing low silicon steel electrical lamination strip
AssigneeInland Steel Company
InventorPrabhat K. Rastogi
Life of this patent
Estimating the term…
Abstract
The chemical composition and processing of a cold rolled steel strip are controlled. Laminations for the core of an electric motor are stamped from the strip and decarburized to produce a lamination having a 1.5 T (15 kG) average core loss value less than about 5.70 W/kg (2.60 W/lb.) and average peak permeability substantially more than about 2000 G/Oe. for a sample thickness of about 0.018 in. (0.46 mm.).
Claims11
In a method for producing cold rolled steel strip for use in electric motor laminations, the steps of:
- providing a steel consisting essentially of the following composition in wt.% before cold rolling:
- ______________________________________ carbon .06 max. manganese .55-.75 silicon .15-.25 aluminum .15-.25 phosphorus .12 max. sulfur .025 max. iron essentially the balance;
- ______________________________________
- hot rolling said steel into steel strip;
- coiling said hot rolled steel strip while the steel is at a coiling temperature in the range 1250.degree.-1400.degree. F. (682.degree.-760.degree. C.) and then allowing said coiled strip to cool;
- cold rolling said steel strip;
- continuously annealing said steel strip at a strip temperature in the range 1250.degree.-1400.degree. F. (682.degree.-760.degree. C.) for about 2-5 minutes, and then allowing said strip to cool;
- and temper rolling said strip to produce a reduction of about 5-7.5%;
- whereby said steel strip, after said temper rolling step, has a grain size and crystallographic orientation which, upon subsequent magnetic annealing at a temperature in the range 1400.degree.-1550.degree. F. (760.degree.-843.degree. C.) for about 1-2 hours in a decarburizing atmosphere, produces an average ferritic grain size of about 3.5-5.0 ASTM and a preponderance of crystallographic planes containing the easiest direction of magnetization.
6 more elements
Dependencies are inferred from the claim text.