DD140568A6 - METHOD FOR PRODUCING SILICLE-SIZED STEEL STRIP - Google Patents

Description

209 252

Verfabren for the production of silicon-containing steel strip field of application of the invention

The invention relates to a method for producing a silicon-containing steel strip of grain-oriented silicon steel for electromagnetic use, according to patent 117 084.

Characteristic of the known technical solutions

It is known to produce steels with a "cube-on-the-tip" weave or Miller indices with a (110 lb. 001) weave, such steels are primarily used as core materials for transformers or other electrical machines. They are characterized by high magnetic permeability combined with low core loss at a given flux density.

These magnetic properties could be further optimized if a process was chosen in which individual grains within a polycrystalline steel sheet are oriented so that the crystal directions giving the best magnetic properties are in the sheet metal.

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level and parallel to the rolling direction.

A "known method for the production of grain-oriented steel sheets is based on the recognition that a finely divided precipitation of manganese sulfide is the cause of the production of a final, well-oriented grain structure.

Object of the invention

It is the object of the invention to provide a steel in a certain form of use, with which in particular the application properties are improved.

Explanation of the essence of the invention

The invention has for its object to provide a process for producing a silicon-bonded steel strip of grain-oriented silicon steel for electromagnetic use, in which a steel melt produced by basic oxygen or open hearth fresh with manganese and with at least one carbide or nitride is seeded, the amount of added Bildners is chosen so that during subsequent treatment of the steel obtained by the melt, the carbides or nitrides form precipitates that promote a preferred formation of some grains in the steel to provide patent 117 084, in which the manganese sulfide dispersion is supported by an excretion of vanadium nitride and the magnetic properties of a steel strip made from a starting material having these two precipitates is improved by an appropriate choice of process parameters.

, 19th ^. 1979

209 252 - 3 - - AP G22C / 209 252

According to the invention the object is achieved in that a silicon steel strip for electromagnetic purposes from a "slab with a Massengebalt of 2 % " to 4% silicon, 0.05 % to 0.1 % manganese, 0.02 % to 0.035% sulfur, 0 , 02% is hot rolled to 0.1% of vanadium in conjunction with minor accompanying elements and the hot strip is cold rolled with a final reduction of at least 70% before the decarburization, at a in the range of 9 ^{(temperature.}

at a temperature in the range of ⁰ to 1050 C 9OO tem-

It is a transformation of the form of the invention that the cold reduced strip is entkohlungsgeglübt at a temperature in the range of 9OO to 1050 ⁰ C temperature, and the decarburization sglühen at 950-1050 ⁰ C side temperature is performed, wherein the decarburization annealing is carried out as a continuous Glihen ,

According to a further embodiment of the invention, the cold reduction takes place in a single stage, the hot strip is annealed and selectively cooled before cold reduction, wherein the annealing of the hot strip takes place at a lying between 9OO and 1100 ⁰ C temperature, and in the practice of the invention, the annealing of Hot strip is carried out at a temperature between 950 and 1075 -C temperature.

The invention is particularly configured to selectively cooling at a rate of 5 to 16 carbon per second up to a lying in the range of 75O to 9OO ⁰ C temperature is carried out, wherein the selective Abkühlen- rapid cooling until almost follows room temperature and the rapid cooling is carried out by means of a natural air flow or compressed air, gas flow or water jet.

19 ^ .1979

2 O 9 2 5 2 ~ ⁴ ~ ^{ΔΡ C22C} / ² ° 9 252

The invention is characterized designed such that the Kaltabnabme is carried out in two stages with an intermediate annealing followed by selective cooling and occurs intermediate annealing at a temperature between 900 and 1100 ⁰ O temperature.

It is a form of practice of the invention that the intermediate annealing be carried out at a temperature in the range of 950 to 1075 ⁰ C, wherein the selective cooling at a rate of 5 to 16 C per second up to a between 750 and 9OO ⁰ C. temperature is followed and that the selective cooling is followed by a rapid cooling to about tree temperature, further to the rapid cooling by means of natural air flow or compressed air, gas flow or water jet is performed.

According to one embodiment of the invention, the hot strip is annealed before the cold picking and annealed particularly advantageous at a lying between 9OO and 1100 ⁰ G temperature, wherein the hot strip annealing is carried out at a lying in the range of and IO75 ⁰ O temperature.

The invention provides that the slab is tempered and hot rolled to a thickness ranging from 1.90 to 3.00 mm, or hot rolled to an approximate thickness of 2.30 to 2.85 mm.

The invention is further embodied in such a way that the geglühte.Warmband at a rate of 5 "is cooled to 16 ⁰ C per second up to a temperature in the range of 75O to 9OO ⁰ C temperature.

19.4.1979 209 25 2 - 5 - AP 022C / 209

It is an advantage of the invention if the cold draw is preferably done in a single step. In this case, the hot strip is best annealed at a temperature in the range of 900 to 1100 ⁰ C temperature and selectively cooled. On the other hand, a two-stage cold reduction with an intermediate annealing can be applied. Then, the intermediate annealing as well as the V / bender annealing should be carried out, followed by the same selective cooling, and the hot strip annealing may possibly be omitted. The second cold decrease should be at least 70 % . The slab is best reheated and rolled hot to a thickness in the range of 1.90 to 3.00 mm, preferably 2.30 to 2.85 mm, whereby a greater cold reduction during rolling to the commercial final dimensions in the range of 0.28 to 0.35 mm is possible. The hot strip is then trimmed and annealed continuously for 2 to 5 minutes at a temperature between 9OO and 1100 ⁰ . A preferred range is 95O to 1075 ⁰ C.

It has been found that the choice of the Küblgeschwindigkeit after this annealing in vanadium-containing steel. Is important in order to achieve the best final magnetic properties. A cooling rate of 5 to 16 ⁰ O per second up to a temperature between 750 and 9OO ⁰ C leads to optimal results, if a faster cooling to about hem temperature follows, for example by natural air flow, compressed air or gas flow cooling or cooling by water jets, ie a two-stage Küblzyklus is applied. This may be associated with the need for excretion of vanadium nitride in a particular morphology after the hot strip

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but with a further coarsening of particles must be prevented, which can occur during prolonged cooling to tree temperature.

After the hot strip, the steel is pickled and cold rolled to the final dimension with or without a low temperature during rolling in a manner in which the final cold reduction is between 70 and 95%. After · cold rolling the steel in a continuous annealing line in an atmosphere of wet nitrogen or a mixture of wet nitrogen / hydrogen and at 900-1050 ⁰ C, preferably in the range of 95O to 1050 ⁰ O, lying temperature for about 4 · Decarburized for minutes. This temperature range for decarburization is significantly higher than the range of 800 to 850 ^° C commonly used for the production of grain oriented steel. It has been found advantageous to thereby eradicate the difficulties otherwise associated with achieving complete secondary recrystallization of this material when the conventional and relatively lower decarburization temperature was used. After decarburization, the tape is coated with magnesia and 24 hours box annealed at a temperature of over 1100 ⁰ O.

Exemplary embodiment

The invention will be explained in more detail by means of exemplary embodiments.

example 1

A molten steel obtained by means of SM-Frischverfabren

Λ9Λ. 1979 209 25 2 - 7 -. AP C22C / 209252

contained in the pan an addition of vanadium such that the total composition was 0.022% carbon, 0.026 % sulfur, 0.0056% nitrogen, 0.092 % manganese, 2.86 %. Silicon and 0.062% vanadium, otherwise iron and had minor accompanying elements. Slabs from blocks obtained with this composition were reheated to 14-00 ⁰ O and rolled at a finishing temperature of 960 ⁰ C to form a hot strip with a thickness of 2.85 mm. The hot strip containing distributed precipitates of manganese sulfide and vanadium now as grain growth inhibitors, was annealed for 5 minutes at 1050 ⁰ C, cooled at a durcbschnittljkhen speed of 10.5 ⁰ C per second to 85O ⁰ C and quenched with oil up to the room temperature , The material was then cold rolled to a final dimension of 0.35 mm. During rolling, it was subjected to aging annealing at 200 ^° C. for 5 minutes for 6 equal-sized thicknesses. After Kaltabnabme the strip was decarburized for 4 minutes at 1050 ⁰ C in hydrogen with a dew point of + 60 ⁰ C before the coating and Kastenglüben • carried out in a conventional manner. A steel produced by this method had a core loss of 1.30 W / kg at 1.7 T and 50 Hz and a permeability of 1.92 T at H s 1.0 kA / m.

Example 2

A product prepared as in Example 1 hot-rolled strip was annealed at 1000 ⁰ 5 minutes Ijang C, cooled at 7.7 ° C / sec at 85O ⁰ C and quenched in oil. After cold rolling to 0.35 n ™ with a similar aging process and decarburizing at 1050 ⁰ C over a period of 5 minutes, the volume in the conventional V / ice was coated and box-

4.1909

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annealed. This steel had a core loss of 1.34 W / kg "at 1.7 T and 50 Hz and a permeability of 1.89 T at H s 1.0

Example 3

A produced as in the preceding examples hot strip material was annealed at IO5O ⁰ C for 5 minutes, cooled at a rate of 11.0 ⁰ C / see to 750 ⁰ C and cold rolled to 0.35 mm, wherein the aging process described above has been applied. After 5 minutes, decarburizing at 1050 ⁰ C, the strip was coated in the conventional manner 'and kästengeglüht. This steel had a core loss of 1.39 W / kg at 1.7 T and 50 Hz and a permeability of 1.89 T at H = 1.0 kA / m.

Example 4.

An example 1 prepared according to the hot strip material was annealed for 2 minutes at 1000 ⁰ C, cooled in air at 15 ° C / sec to 9OO ^P C and then quenched in oil at about room temperature. The annealed hot-rolled strip was then cold-rolled with aging treatment to 0.35 mm, decarburized for 4 minutes at 1000 ⁰ C and 24 hours box annealed at 1200 ⁰ G. The steel produced in this way had a core loss of 1.32 W / kg at 1.7 T and 50 Hz and a permeability of 1.89 T at H = 1.0 kA / m. ,

Example 5

The hot strip was produced as in Example 4, but with the difference that the hot strip after the first

4.1979 20925 2 -9 ~ AP C22C / 209252

Annealing was 6 ⁰ C / sec cooled to 9OO ⁰ C and then quenched in oil to about room temperature. The steel produced in this way had a core loss of 1.34 WAs at 1 »7 pounds and -50 Hz and a permeability of 1.89 T at H = 1.0 kA / m.

Example 6

A product prepared according to Example 1, the hot strip material was annealed for 2 minutes at 1050 ⁰ C and cooled at 8 ⁰ C / see 9OO to ⁰ C before it was quenched in oil at about room temperature. The annealed hot strip was then rolled down to 0.35 mm with aging, decarburized for 4 minutes at 1050 ⁰ C and box annealed at 1200 ⁰ C for 24 hours. The steel produced in this way had a core loss of 1.30 W / kg at 1.7 T and 50 Ez and a permeability of 1.93 T at H = 1.0 kA / m.

Example 7

A product prepared as in Example 1 was initially hot strip annealed at 1025 ⁰ C for 2 minutes, then cooled in air at 16 ⁰ C / see 9OO to ⁰ C and quenched in oil at room temperature. The annealed hot strip was then under. Cold rolled, decarburized for 4 minutes at 1050 ⁰ C and box-annealed at 1200 ⁰ C for 24 hours. The steel produced in this yippee had a core loss of 1.37 WAs at 1.7 T and .50 Hz and a permeability of 1.88 T at H = 1.0. came.

Example 8

The same hot strip material was processed as in Example 7, but the decarburization became 4 minutes long

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"-vorgenommen at 1000 ⁰ C. This steel had a core loss of 1.34 W / kg at 1.7 T and 50 Hz and a permeability of 1.89 T at H = 1.0 kA / m.

Example 9.

A StablprobQ of the material of Example 1 was calcined for 5 minutes at 950 ⁰ G, cooled at 5 ° C / sec to 85O ⁰ C and cooled with compressed air to room temperature / The sample was cold rolled without aging, decarburized for 4 minutes at 1050 ⁰ C. to box for 24 hours at 1200 ⁰ C. The steel produced in this way had a core loss of 1.36 W / kg at 1.7 T and 50 Hz and a permeability of 1.91 T.

Claims (22)

Anspruch [en] A process for producing silicon-bonded steel strip of grain oriented silicon rod for electromagnetic use, in which a steel melt produced by basic oxygen or open hearth is manganese-seeded with manganese and at least one carbide or nitride former, with the amount of added former selected in that, during subsequent treatment of the steel obtained from the melt, the carbides or nitrides form precipitates which promote preferential formation of some grains in the steel according to patent 117 084, characterized in that a slab with a mass content of 2 % to 4% silicon, 0.05 % to 0.1% manganese, 0.02% to 0.035 % sulfur, 0.02 % to 0.06 % carbon, 0.002 % to 0.01% nitrogen and 0.01% to 0.1 % vanadium , in connection with minor impurities, is hot rolled to a sheet, and the hot strip with a final decrease of at least 70 % before decarburization at between 9OO and 1050 0 lying cold rolled. 2. The method according to item 1, characterized in that the cold-reduced strip is decarburization annealed at a lying in the range of 9OO to 1050 ⁰ C temperature. 3. The method according to item 2, characterized in that the Entkoblungsglühen at a zi
lying temperature takes place. Decoctivating annealing at between 95Ο and 1050 ^0. 4; 1979 - 14 - AP 022C / 209 4.1979 - 13 - AP C22C / 209252 4. The method according to item 3 or 4, characterized in that the Entkoblungsglühen as a continuous annealing. is carried out. O Γ OU'i üDi) - \ U 7 ti -χ η v 5. The method according to points 1 to 4, characterized in that the cold reduction takes place in a single stage and the hot strip annealed and is cooled selectively before the cold decrease. 6, method according to point 5 »characterized in that the annealing of the hot strip takes place at a temperature lying between 9OO and 1100 ⁰ O, 7 · Method according to item 6, characterized in that the annealing of the hot strip takes place at a temperature lying between 95O and IO75 0. 8. The method according to the items 5 »6 or 71, characterized in that the selective cooling is carried out at a rate of 5 to 16 ⁰ C per second up to a lying in the range of 750 to 9OO ⁰ C temperature. Method according to points 5 to 8, characterized in that the selective cooling is followed by rapid cooling to near room temperature. 10. The method according to item 9, characterized in that the rapid cooling "by means of a natural air flow or compressed air, gas flow or water jet takes place", 11. The method according to items 1 to 4, characterized in that the Kaltabnabme is carried out in two stages with an intermediate annealing and subsequent selective cooling. 209 252 12, method according to item 11, characterized in that the intermediate annealing in a
lying temperature takes place. the intermediate annealing "at between 9OO and 1100 ⁰ G 13. The method according to item 12, characterized in that the intermediate annealing is carried out at a lying in the range of 95O and IO75 ⁰ C temperature. 14. The method according to points 11, 12 and I3, characterized in that the selective cooling is carried out at a rate of 5 to 16 ⁰ C per second up to a lying between 750 and 9OO ⁰ C temperature. 15. Method according to items 11 to 14, characterized in that the selective cooling is followed by a rapid cooling to about room temperature. 16. The method according to item 15, characterized in that the rapid cooling by means of natural air flow or compressed air, gas flow or water jet is performed. 17. The method according to items 11 to 16, characterized in that the hot strip is annealed before the cold take-off. 18. The method according to item 17, characterized in that the hot strip at a zwisc
the temperature is annealed. the hot strip at a between 9OO and 1100 ⁰ C. 19. The method according to item 18, characterized in that the hot strip annealing is performed at a lying in the range of 950 and 1075 G temperature. 19.4-.1979 209 25 2 - 12 - AP C22C / 209 19.4.1979 209 25 2 -H-AP G22C / 209 252 invention claim 20. Method according to points 1 to 19 », characterized in that the slab is tempered and hot-rolled to a thickness lying in the range of 1.90 to 3.00 mm. , 21. The method according to item 20, characterized in that the slab to a between 2.30. and 2.85 mm lying thickness is hot rolled. 22. The method according to points 1 to 21, characterized in that the annealed hot strip is cooled at a rate of 5 to 16 ⁰ O per second to a lying in the range of 750 to 900 ⁰ C temperature.