SU840143A1 - Method of annealing isotropic electroengineering steel - Google Patents

Description

The invention relates to metallurgy, in particular, to the search for a method for the heat treatment of isotropic electrical steel used for the manufacture of magnetic conductors of electrical machines, devices and instruments. Methods are known for the manufacture of isotropic electrical steel, which are based on the formation of the structure and, consequently, the magnetic properties in the process of decarburization annealing. In this case, decarburization is carried out both before Hopo, IS rolling, and in the cold strip (strip. There is a known method of thermal treatment of electrical steel, in which decarburized annealing at 65 ° -9OO ° C for 6-6 O hours is subjected to hot rolled iron, and cold bath at 600-600 ° C is subjected to hot rolled iron, and cold bath at 6-6 O h is subjected to hot rolled iron, and cold bath at 6-6 O h is subjected to hot rolled iron, and cold bath at 6-6 O h is subjected to hot rolled iron, and cold bath at 6-6 O h is subjected to hot rolled iron, and cold bath during cold cooking at 6-6 O h, hot rolled iron is removed, and cold bath is heated by cold stripping at 65 ° -9OO ° C for 6-6 O h, hot rolled iron is poured, and cold bath is heated by cold rolling at 65 ° -9OO ° C for 6 to 6 O h, hot rolled iron is poured, and cold bath is heated by cold cooking at 65 ° C to 9 ° C during 6 to 6 ° H, hot rolled iron is removed. The strip is annealed in a continuous furnace at 800–1175 ° C for no more than 5 min. l However, the known method requires two decarburizing anneals. The closest to the proposed PS technical essence and the pe-i pulp achieved is of a graded iron-silicon sheet, which provides for single cold rolling of a metal with a content,%: silicon 0.5-3.8, carbon 0, O2-0, O8 and aluminum up to 0.5 for the final thickness and two-time decarburization annealing of Metal, First The decarburization annealing is carried out in a continuous unit at 1065-1205 ° C to a carbon content in steel O, O1O, O25%. The second decarburizing annealing to a carbon content in metal less than O, O1% is carried out at a temperature of 76 ° C-927 ° C. The surface of strip 2 is etched between the first and second decarburization anneals. The disadvantages of this method are low magnetic properties, since the structure obtained during the decarburization process is unevenly coarse-grained from the surface and fine-grained in the middle of the strip thickness. Kromr, the known method is more time consuming since between the two decarburization anneals, strip etching is necessary.

After processing by a known method, electrical steel with a silicon content of 3, O5% has the following magnetic properties.

Unit loss

Р 1.5 / 50, W / kg3.37

Magnetic induction

2590

1.57 Anisbtropi magnetic 0.1

induction .t

The purpose of this invention is to improve the magnetic properties.

This goal is achieved by the fact that in the annealing method, which includes decarburization annealing at 100 ~ 1100 ° C, holding, cooling to 7 ° -40 ° C, holding, heating to 920-99 ° C, holding, and cooling at ZOO-58O speed deg / min, and heating - at a speed of 30-60 degrees / min.

To carry out the method, a hot-rolled strip with a silicon content of 0.83, 5%, carbon O, O15-O, OV% and aluminum 0.01-0.6% after etching the scale is subjected to one-time cold rolling for final tolgcine and decarburization annealing, starting with heating up to the temperature range lOOO-llOO C, being kept at this temperature for 30 ° C, then cooled at a speed of 3OO-580 C / min to an intermediate temperature of 800 ± 4 ° C, kept at

this temperature for 30–6 ° C and again is continuously heated at a speed of 30–60 C / min to a temperature range of 920–990 0, is held at this temperature for 30–20 s.

When the temperature of the onset of decarburization is 10OO-1100 0 within 30-120 s from the surface to the middle of the strip thickness, it starts at the expense of J — about 1% rotation, ferritic columnar growth of x grains. With

after the next cooling at the rate of ZOO-bVO-C / min to an intermediate temperature of 80 ° -40 ° C, carbon remains in the solid solution, which ensures continuous columnar growth of ferritic grains

in the case of a continuous transition from a speed of KOZO60 s / min from the intermediate temperature to the final temperature range of decarburization, 92O-990 ° C. As a result of this non-spinning decarburization process, the structure of the steel treated by the proposed method is characterized by a large columnar ferritic grain.

Heat treatment of electrical steels, the chemical composition of which is given in table. 1, is carried out in accordance with the proposed method in a moist protective atmosphere containing 25% hydrogen and 75%

nitrogen.

Table 1

10.027 O, 22 3.05 0.005 0.010 2O, O42 O, 22 O, 85 0, O07 O, OO9

Metal decarburization starts from heating to the temperature range of 10 UNO C, then continues at intermediate temperature C and ends in the temperature range of 920-99 ° C. Cooling rate to intermediate

temperature is 300.440 and

5800С

per minute, and the transition to the final temperature range is carried out at a rate of 30.45 and 6 ° C per minute.

Claims (2)

The magnetic properties of electrical steel, processed by the proposed method, are given in table. 2. 0.08 0.07 ODO O, 37 O, O6 0, O9 0.1 O OD7 The proposed method for the heat treatment of isotropic electrical steel reduces the specific losses and increases the magnetic induction, which ensures a reduction in power losses and a reduction in the dimensions of the electromachine The invention method of annealing an isotropic electrical steel, including decarburizing annealing at 1000-1, table 2 and cooling to 760-84 ° C, holding, heating to 92 ° C-990 ° C, holding, characterized in that, with a chain of improved magnetic properties, cooling n botfly at a rate zoo; 580 deg / min, and heating - with ss osgue ZO-6O hail-min. The sources of information are gfinty in consideration during the examination 1.Patent of France No. 1318791, cl. From 21D 1/78, published. 1963. 2. The patent of Germany No. 1259923, cl. 18 On 1/78, 1971.