CS245859B1 - Cold rolled isotropic strip production method for antimony alloyed silicon steel electrotechnics - Google Patents

Abstract

The method of producing cold-rolled isotropic strips for electrical engineering from antimony-alloyed silicon steel solves the problem of improving the magnetic properties of these strips. The starting semi-finished product is a sheet metal strip, hot-rolled to a thickness of 1.7 to 2.2 mm. The semi-finished product is cold-rolled to a thickness of 0.30 to 0.65 mm and then annealed for 2 to 20 minutes at a temperature of 80 to 180 °C above the Curie temperature of the respective antimony-alloyed silicon steel. Preferably, the strip is annealed in a protective atmosphere for 30 to 180 minutes at a temperature of 800 to 950 °C before cold rolling in a positive correlation of the temperature with the ratio of the silicon content in weight percent to the antimony content in weight percent in the semi-finished product.

Description

245359

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of cold rolled isotropic bands for antimony alloyed silicon steel electrotechnics and solves the problem of improving magnetic properties.

Isotropic cold rolled sheets and strips are widely used in the electrical industry. Their quality is dependent on the basic characteristics of electrical machines, such as efficiency with direct influence on the economical use of electricity. The current technology of sheet isotropic strips is based on the following main operations: steel production in co-converters or other metallurgical steel-making furnaces, mold casting, eventual continuous casting, hot rolling rolling, hot-rolled rolling , pickling and continuous cold rolling on tandem tracks. Further, the end-crimped strip undergoes thermal and chemical-thermal treatment at substantially constant temperatures irrespective of their characteristics. These isotropic cold-rolled sheets and sheets are produced in depths of 0.5 to 0.65 mm in several quality groups. The final heat treatment in the atmosphere and the carrying of the insulating coating is carried out on special so-called so-called dynamic lines. The resulting magnetic properties of the isotropic bands depend on the chemical composition of the steel used, the deformation parameters, the heat treatment parameters and the composition of the annealing atmosphere. The finished product, the isotropic strip, has a homogeneous microstructure formed by crystallographically oriented oriented grains. Accordingly, in the microstructure of the product, grains crystallographically oriented substantially in the direction of magnetization are present and statistically evenly distributed. The scientific publications provide theoretical and experimental evidence that the crystallographic direction, according to Muller indices <111>, is the energy-disadvantageous and most difficult direction of magnetization over the type of material. The technology for producing cold rolled isotropic bands must be designed so that the resulting magnetic properties in all directions are the same - isotropic. At present, the methods of production and technology described above, as well as the chemical composition of the steels used, no longer provide a guideline without further high investment costs to substantially improve the magnetic properties. For isotropic belts made in particular with antimony alloyed silicon steel, this method is already ineffective because the magnetic characteristics of the strips and sheets of them are not optimally achieved. These are antimony-coated silicon steel with a composition based on composition of 0.6 to 2.9% silicon, 0.02 to 0.06% carbon, 0.1 to 0.4% manganese, up to 0.03% phosphorus and to 0.03% sulfur. Other essential modifiers are 0.01 to 0.15% antimony, up to 0.008% nitrogen to 0.08 to 0.4 aluminum.

Other preferred components are 0.01 to 0.05% of chromium, 0.01 to 0.05% of nickel, up to 0.1% of the medium, to 0.15% of zirconium, up to 0.5% of zirconium, up to 0.15% of zirconium. % tin.

The above drawbacks are solved by the problem of cold rolled isotropic belts made of antimony alloyed silicon steel for the electrotechnics of the present invention, which is based on the fact that the strips are cold rolled from semi-commodity with a thickness of 1.7 to 2.2 mm. 30 to 0.65 mm and then annealed for 2 to 20 minutes at 80 DEG to 180 DEG C. under the temperature of the respective antimony alloyed silicon steel. Preferably, the preform is cold rolled at 800 to 950 ° C in a protective atmosphere for 30 to 180 minutes prior to rolling. The advantages of the process according to the invention are mainly in the minimization and / or minimization. limiting the ingress of grain oriented in the bore of the magnet in the produced strip or sheet. In the article, a crystal-graphical and hence a magnetic texture is produced, expressed according to the Muller indices {001} <uvo>, wherein the grain level in the sheet is oriented such that the crystallographic axis [100] is parallel to the plane of rolling. the resulting magnetic properties of the metallic matrix compared to the ple-breeding magnetic properties of random statistical representation. The examples of the process according to the invention are:

Steel produced in the LD Processor converter cast at a temperature of 1534 ° C with a weight composition of elements in the melt analysis: carbon 0.03%, manganese 0.33 ° / o, silicon 2.34 ° / o, phosphorus 0.008 ° (o), sulfur 0.009 ° / o, aluminum 0.120 ° / o, nitrogen 0.008%, oxygen 0.006% amodified by added ferroantimone in an amount of 10 to 25 kg resulting in antimony concentration in the steel in the range 0.02 to 0.05% by weight . after hot rolling, 0.04 to 0.05% by weight. The hot rolled sheet on a 1.8 mm thick strip is stationary annealed, with a temperature of 940 ° C in a protective atmosphere of 120 minutes. Heating is followed by controlled cooling at a rate of up to 300 degrees Celsius / hour. Thereafter, the sea strip is cold rolled with a total deformation of 72.2% at a depth of 0.5 mm. The final processing is carried out on a two-stage line and a decarburization zone at 850 ° C and a technological speed of 38 m / minute. The re-crystallization annealing takes place at a temperature of 920 ° C. A protective shielding atmosphere is used for both annealing.

Claims (2)

1. Method of manufacturing cold rolled isotropic electrical belts of antimony alloyed silicon steel, characterized in that the strip is cold rolled from a blank of thickness 1.7 to 2.2 mm to a thickness of 0.30 to 0.65 mm and they are then calcined for 2 to 20 minutes at a temperature of 80 to 180 degrees Celsius above the Curie temperature corresponding to the antimony alloyed silicon steel. invention 2. A process according to claim 1, characterized in that the blank 1.7 to 2.2 mm thick is annealed at 800 to 950 ° C in a protective atmosphere for 30 to 180 minutes before being cold rolled, the annealing temperature being in a positive correlation with the ratio of silicon content to antimony content in the blank.