CS245859B1 - Method of cold rolled isotropic bands production for electrotechnics from antimony alloy silicon steel - Google Patents

Abstract

Process of cold rolled production of isotropic bands for antimony electrotechnics alloyed silicon steel problem of improving magnetic properties these belts. The starting material is a sheet metal sheet, rolled hot, at a ridge of 1.7 to 2.2 mm, The blank is rolled cold to the ridge From 0.30 to 0.65 mm and then calcined for 2 to 20 minutes at 80 to 180 ° C above Curie temperature of the respective antimony alloy silicon steel. Preferably the strip is annealed in a protective before cold rolling atmosphere at 30 to 180 minutes at room temperature 800 to 950 ° C in a positive temperature correlation with a ratio of silicon content by weight perceint to antimony v content percent by weight in the blank.

Description

The invention relates to a process for the production of cold-rolled isotropic strips for electro-technology made of antimony-alloyed silicon steel and to the problem of improving magnetic properties.

Isotropic cold rolled sheets and strips are widely used in the electrical industry. Depending on their quality, the basic characteristics of electrical machines, such as the efficiency with a direct impact on the economical use of electricity.

The current technology of isotropic strips and sheets is based on the following main operations: production of steel in convectors or other metallurgical furnaces for steel production, casting into chillies, eventually on continuous-casting equipment, hot rolling on weakening, hot rolling track, morethe and continuous cold rolling on tandem tracks. The strip rolled to the final depth is further subjected to a thermal and chemico-thermal treatment at substantially constant temperatures without regard to their characteristics. These cold-rolled isotropic strips and sheets are produced in thicknesses of 0.5 to 0.65 mm in several quality groups. The final heat treatment in the atmosphere and on the bearing of the insulating coating is carried out on special so-called. dynamo-lines.

The resulting magnetic properties of the isotropic bands are dependent on the chemical composition of the steel used, the deformation parameters, the heat treatment parameters and the annealing atmosphere composition. The finished product, the isotropic strip, has a h-omogenic microstructure formed by crystallographic randomly oriented dissipations. It follows that grains crystallographically oriented in the t-direction of magnetization are present and statistically evenly present in the microstructure of the product.

The scientific publications provide theoretical and experimental evidence that the crystallographic direction, according to the Müller indexes <111>, is the energy-disadvantageous and most difficult direction of magnetization for this type of material. The technology of cold-rolled isotropic strip production itself must be designed so that the resulting magnetic properties in all directions are rectangular - isotropic. The above-described methods and technologies of production, as well as the chemical composition of the used steels, no longer offer prospects without further high investment costs for substantially improving the magnetic properties. For isotropic belts made especially of antimony-alloyed silicon steel, this method proves to be ineffective since the values of the magnetic characteristics of the belts and of the sheets are not optimally achieved. It is an antimony alloyed silicon steel having a weight basis of compounding of 0.6 to 2.9% silicon, 0.02 to 0.06% carbon, 0.1 to 0.4% manganese, to 0.03% phosphorus and up to 0.03% sulfur. Other essential modifier components are 0.01 to 0.15% antimony, to 0.008% nitrogen, and 0.08 to 0.4 aluminum.

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

The problem is solved by a process for the production of cold-rolled isotropic strips from antimony-alloyed silicon steel for electrical engineering, according to the invention, which consists in that the strips are cold-rolled from a blank of thickness 1.7 to 2.2 mm to a thickness of 0.30 to 0.65 mm and the p-rotations are annealed for 2 to 20 minutes at a temperature of 80 to 180 ° C above the Curie temperature corresponding to the antimony-alloyed silicon steel. Preferably, the blank is annealed at 800 to 950 ° C in a protective atmosphere for 30 to 180 minutes before cold rolling.

The advantages of the method according to the invention are mainly in minimizing, respectively. limitations of the presence of grains oriented in the heavy direction of magnetization in the perforated strip or sheet. In the product, the crystallographic and thus also the magnetic texture is expressed in terms of the Muller indices {001}, with most grains in the plane of the sheet being oriented so that the crystallographic axis [100] is parallel to the rolling plane. This results in an improvement of the resulting magnetic properties of the metal matrix in the p-ornation with the magnetic properties of the sheets with a random statistical representation of the grains.

Examples of the process according to the invention:

Steel produced in the LD converter by the process and cast at a temperature of 1 534 ° C with the mass composition of the elements in the melting 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% and modified by adding ferroantimone to the ingot mold in an amount of 10 to 25 kg to a final antimony concentration in steel r ranging from 0.02 to 0.05 wt. after hot rolling 0.04 to 0.05% by weight. The hot rolled sheet is annealed at a temperature of 940 [deg.] C. in a protective atmosphere for 120 minutes, onto a strip of 1.8 mm thickness. The heating is followed by controlled cooling at a rate of up to 300 degrees Celsius per hour. Then, the strip of seas is sealed and cold rolled by a total deformation of 72.2% to a depth of 0.5mm. The final treatment is carried out on a two-stage line in a decarburization zone at 850 ° C and a technological speed of 38 m / min. The recrystallization annealing is carried out at a temperature of 920 ° C. A conventional protective atmosphere is used for both annealing.

Unmeasured magnetic properties:

P 1.0 / 50 1.46 to 1.66 W / kg B 5 000 1.62 to 1.68 T P 1.5 / 50 3.86 to 4.02 W / kg B 10 000 1.74 to 1.78 T P 1.7 / 50 5.26 to 5.60 W / kg

SUBJECT

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.