CN104962816B - A kind of very thin directional silicon steel and its short route manufacture method - Google Patents

Abstract

An ultra-thin oriented silicon steel plate and its short-process manufacturing method, the composition of the steel plate is C 0.002-0.08%, Si 2.8-3.4%, Mn 0.05-0.30%, S 0.015-0.04%, Als 0.005-0.05% by mass percentage , N 0.003~0.010%, Cu 0~0.6%, Sn 0~0.2%, O<0.004%, P<0.01%, the balance is Fe; its product thickness is 0.05~0.15mm; the manufacturing method includes: (1) Smelting molten steel; (2) continuous casting to obtain cast strip; (3) hot rolling and coiling after cooling; (4) controlled cooling after normalization treatment; (5) cold rolling once after pickling; then intermediate annealing; (6) ) secondary cold rolling after pickling; then decarburization annealing; (7) coating annealing separator; (8) purification annealing after high temperature annealing. The method of the invention greatly simplifies the production process flow of the ultra-thin oriented silicon steel, and the production method is simple and effective, and has the characteristics of short flow process, easy control and low energy consumption.

Description

An ultra-thin oriented silicon steel plate and a short-process manufacturing method thereof

technical field

The invention belongs to the field of electrical steel manufacturing, and in particular relates to an ultra-thin oriented silicon steel plate and a short-flow manufacturing method thereof.

Background technique

Grain-oriented silicon steel (including ordinary grain-oriented silicon steel and high magnetic induction grain-oriented silicon steel) is a soft magnetic material containing about 3% silicon. Due to its strong {110}<001> Gauss texture, it has a very low Iron loss and very high magnetic induction intensity, mainly used in the manufacture of transformer cores; it is the only product in the iron and steel industry that uses the secondary recrystallization phenomenon, and is a relatively successful application of texture control technology in industrial production; by reducing the orientation The iron loss of silicon steel and saving a lot of electric energy is the goal that people pursue unremittingly. Reducing the thickness of grain-oriented silicon steel products has become the main method to achieve low iron loss of grain-oriented silicon steel.

However, the production of oriented silicon steel by the conventional secondary recrystallization method has a thickness limit of the finished product, which is generally about 0.15mm. When the thickness is lower than this thickness, the secondary recrystallization of the finished product is not perfect, or secondary recrystallization cannot occur. As a result, the magnetic properties are very poor, and the required service performance cannot be achieved; in order to obtain oriented silicon steel thin strips with a thickness of ≤0.15mm, people now use the three-time recrystallization production process as follows: First, use the traditional production process to obtain 0.20~0.35mm thick The secondary recrystallized oriented silicon steel is cold-rolled to a target thickness of 0.15mm or less after removing the glass film and insulating film on the surface of the finished plate, and then annealed at 750~1000°C to obtain an extremely thin strip of oriented silicon steel by triple recrystallization; the above The defects in the production process are: the thin strip is easy to crack and break during cold rolling, and the cold rolling efficiency is low; moreover, the current process needs to use the finished plate of oriented silicon steel as raw material, and the traditional production process of oriented silicon steel has many product defects. , low yield, high energy consumption, serious environmental pollution and other shortcomings.

Contents of the invention

The object of the present invention is to provide a kind of ultra-thin grain-oriented silicon steel plate and its manufacturing method with short process; The present invention makes full use of twin-roll strip continuous casting technology and secondary recrystallization method, has obtained ultra-thin grain-oriented silicon steel product, and this method has short The characteristics of process flow, easy control and low energy consumption.

The composition of the ultra-thin oriented silicon steel of the present invention is C 0.002-0.08% by mass percentage, Si 2.8-3.4%, Mn 0.05-0.30%, S 0.015-0.04%, Als 0.005-0.05%, N 0.003-0.010%, Cu 0~0.6%, Sn 0~0.2%, O<0.004%, P<0.01%, the balance is Fe.

The magnetic induction B ₈ of the above-mentioned ultra-thin grain-oriented silicon steel is 1.72~1.83T.

The iron loss P _10/400 of the above-mentioned ultra-thin oriented silicon steel is 6.6~8.1W/kg, and the P _10/1000 is 19.2~27.2W/kg.

The thickness of the above-mentioned ultra-thin grain-oriented silicon steel is 0.05-0.15mm.

The short-flow manufacturing method of ultra-thin grain-oriented silicon steel of the present invention is carried out according to the following steps:

The present invention provides a method for manufacturing the above-mentioned ultra-thin oriented silicon steel plate, which comprises the following steps:

1. Smelting molten steel, the composition of molten steel by mass percentage is: C 0.002~0.08%, Si 2.8~3.4%, Mn 0.05~0.30%, S 0.015~0.04%, Als 0.005~0.05%, N 0.003~0.010%, Cu 0 ~0.6%, Sn 0~0.2%, O<0.004%, P<0.01%, the balance is Fe;

2. Using a twin-roll strip continuous casting device, the molten steel is poured through the tundish into a cavity composed of two crystallization rollers and two side sealing plates to form a molten pool, and the upper surface superheat of the molten pool is controlled to be 10-70°C. The molten steel in the molten pool solidifies with the rotation of the crystallization roller and is exported at a speed of 20-60m/min to obtain a cast strip;

3. The cast strip is cooled by the cooling unit at a speed of 20-100°C/s and then hot-rolled. The rolling start temperature is 900-1150°C, the hot-rolling reduction rate is 15-50%, and the final rolling temperature is above 800°C. After hot rolling, cool at a rate of 20~100°C/s to below 650°C and coil to obtain hot rolled coils;

4. Normalize the hot-rolled coil at a temperature of 850-1150°C for 1-10 minutes. After normalization, perform controlled cooling at a cooling rate of 5-50°C/s, and cool to normal temperature to obtain a normalized sheet;

5. Pickle the normalized plate to remove the surface oxide scale, and then conduct a cold rolling with a reduction rate of 40-70%; then perform an intermediate annealing at a temperature of 800-1100°C for 3-10 minutes to obtain intermediate annealing plate;

6. Pickling the intermediate annealed sheet to remove the surface oxide scale, and then carry out secondary cold rolling, the reduction rate of the secondary cold rolling is 70~98%; then carry out decarburization annealing, the temperature is 800~900°C, and the time is 3~ 10min;

7. Coating annealing separator on the surface of the plate after decarburization annealing;

8. Heat the plate coated with annealing release agent to 800±10°C, then raise the temperature to 1200±10°C at a rate of 10~30°C/h to complete high-temperature annealing, and then keep it at 1200±10°C for at least 20 hours to complete the purification Annealing, and finally uncoiling, flattening, stretching annealing and insulating layer coating to make ultra-thin oriented silicon steel plate.

The above-mentioned casting belt has a width of 100-2000mm.

In the above method, the length of the contact arc between the molten steel in the molten pool and the surface of the crystallization roller is 100-250 mm, and the height of the molten pool is 80-220 mm.

In the above method, the atmosphere during the intermediate annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 50%, and the dew point of the mixed gas is 20-45°C.

In the above method, the atmosphere during decarburization annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 50%, and the dew point of the mixed gas is 20-45°C.

In the above method, the atmosphere during high-temperature annealing is a mixed atmosphere of hydrogen and nitrogen, and the volume percentage of hydrogen is 75%, and the atmosphere during purification annealing is a hydrogen atmosphere.

Twin-roll thin strip continuous casting is a technology in which two counter-rotating cooling rolls are used as crystallizers to directly produce thin strips with liquid metal. Utilizing its sub-rapid solidification (10 ² ~10 ⁴ ℃/s) characteristics, more inhibitor-forming elements can be dissolved in the cast strip to obtain more, more dispersed and finer inhibitor particles , improve inhibition. In addition, the thickness of cast slab obtained by thin strip continuous casting technology is usually only 1~5mm, which is much smaller than the thickness of conventional continuous casting slab (50~200mm), which can greatly simplify the hot rolling process. All of these will be beneficial to the preparation of ultra-thin grain-oriented silicon steel sheets. It can be seen that the application of twin-roll thin strip continuous casting technology to the production of ultra-thin oriented silicon steel plate has incomparable advantages.

Features and beneficial effects of the present invention are:

(1) Based on the twin-roll thin strip continuous casting technology, a 0.05-0.15mm thick ultra-thin oriented silicon steel plate is prepared by the secondary recrystallization method, which breaks through the traditional triple recrystallization method;

(2) No other elements are added, only conventional AlN and MnS are used as inhibitors, and it is easier to control the number, distribution and size of inhibitor particles under strip continuous casting conditions;

(3) The production process of ultra-thin oriented silicon steel is greatly simplified, the manufacturing method is simple and effective, and has the characteristics of short process, easy control and low energy consumption.

Description of drawings

Fig. 1 is a schematic flow chart of the short-flow manufacturing method of the ultra-thin grain-oriented silicon steel sheet of the present invention.

detailed description

The contact arc length in the embodiment of the present invention and the comparative example is 100-250 mm, and the height of the molten pool is 80-220 mm.

The crystallization roll diameter of the twin-roll continuous casting device used in the examples and comparative examples of the present invention is 500-1000 mm.

The width of the cast strips obtained in the examples of the present invention and the comparative examples is 100-2000 mm.

The magnetic performance data of the products in the embodiment of the present invention and the comparative example are obtained by using a single-chip test method on a MATS-2010M magnetic performance tester.

The annealing separator used in the embodiment of the present invention is magnesium oxide.

In the embodiment of the present invention, the atmosphere during the intermediate annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 50%, and the dew point of the mixed gas is 20-45°C.

In the embodiment of the present invention, the atmosphere during decarburization annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 50%, and the dew point of the mixed gas is 20-45°C.

In the embodiment of the present invention, the atmosphere during high-temperature annealing is a mixed atmosphere of hydrogen and nitrogen, and the volume percentage of hydrogen is 75%, and the atmosphere during purification annealing is a hydrogen atmosphere.

Example 1

The molten steel composition of ultra-thin grain-oriented silicon steel sheet is C 0.04%, Si 3.0%, Mn 0.18%, S0.022%, Als 0.025%, N 0.0095%, O<0.004%, P<0.01%, and the balance is Fe; magnetic induction B ₈ is 1.80T, iron loss P _10/400 is 6.6W/kg, P _10/1000 is 22.0 W/kg, thickness 0.1mm;

The molten steel for smelting has the same composition as above;

A twin-roll strip continuous casting device is used to pour molten steel through the tundish into a cavity composed of two crystallization rollers and two side sealing plates to form a molten pool. The upper surface superheat of the molten pool is controlled at 40°C, and the molten steel in the molten pool Solidified with the rotation of the crystal roll and exported at a speed of 40m/min to obtain a cast belt;

The cast strip is cooled by the cooling unit at a speed of 60°C/s and then hot-rolled. The rolling start temperature is 1000°C, the hot-rolling reduction rate is 33.3%, the final rolling temperature is above 800°C, and the hot-rolling temperature is 60°C/s. Cool at a speed below 650°C and coil to obtain hot-rolled coils;

The hot-rolled coil was subjected to normalization treatment at a temperature of 1000°C for 5 minutes, controlled cooling after the normalization treatment at a cooling rate of 25°C/s, and cooled to normal temperature to obtain a normalized sheet;

Pickle the normalized plate to remove the surface oxide scale, then conduct a cold rolling, the reduction rate of the first cold rolling is 50%; then perform intermediate annealing at a temperature of 950 ° C for 6 minutes to obtain an intermediate annealed plate;

Pickling the intermediate annealed sheet to remove the surface oxide scale, and then performing secondary cold rolling, the reduction rate of the secondary cold rolling is 88%; then performing decarburization annealing, the temperature is 850°C, and the time is 6 minutes;

Coating an annealing separator on the surface of the plate after decarburization annealing;

Heat the plate coated with annealing release agent to 800±10°C, then raise the temperature to 1200±10°C at a rate of 20°C/h to complete high-temperature annealing, and then keep it at 1200±10°C for 20 hours to complete purification annealing, and finally unwind , flat stretch annealing and insulating layer coating, made of ultra-thin grain-oriented silicon steel plate;

Molten steel with different components was used for comparison experiments as above, and the components were C 0.05%, Si 3.1%, Mn 0.04%, S 0.05%, Als 0.01%, N 0.02%, O<0.004%, P<0.01% according to the mass percentage , the balance is Fe; the magnetic induction B ₈ of the obtained silicon steel plate is 1.66T, the iron loss P _10/400 is 11.2W/kg, and the P _10/1000 is 28.5 W/kg.

Example 2

The molten steel composition of ultra-thin grain-oriented silicon steel sheet is C 0.002%, Si 2.8%, Mn 0.05%, S0.015%, Als 0.005%, N 0.003%, Cu 0.3%, Sn 0.1%, O<0.004%, P<0.01%, the balance is Fe; magnetic induction B ₈ is 1.72T, iron loss P _10/400 is 8.1W/kg, P _10/1000 is 19.2W/kg, thickness 0.05mm;

Manufacturing method is the same as embodiment 1, and difference is:

(1) Molten steel for smelting, with the same composition as above;

(2) The superheat degree on the upper surface of the molten pool is 10°C, and the molten steel is exported at a speed of 60m/min;

(3) The cast strip is cooled at a rate of 20 °C/s, the hot rolling start temperature is 900 °C, the reduction rate is 15%, and the hot rolling is cooled at a rate of 20 °C/s;

(4) The normalization treatment temperature is 850°C, the time is 10min, and the normalization treatment cooling rate is 5°C/s;

(5) The first cold rolling reduction rate is 40%; the intermediate annealing temperature is 800°C, and the time is 10 minutes;

(6) The reduction rate of the secondary cold rolling is 98%; the decarburization annealing temperature is 800°C, and the time is 10 minutes;

(7) Heat the plate coated with annealing release agent to 800±10°C, then raise the temperature to 1200±10°C at a rate of 10°C/h to complete high-temperature annealing, and then keep it at 1200±10°C for 24 hours to complete the purification annealing;

Molten steel with different components was used for comparative experiments in the above manner, and the components were C 0.06%, Si 3.0%, Mn 0.4%, S 0.03%, Als 0.03%, N 0.009%, O<0.004%, P<0.01% according to the mass percentage , the balance is Fe; the magnetic induction B ₈ of the obtained silicon steel plate is 1.62T, the iron loss P _10/400 is 11.1W/kg, and the P _10/1000 is 29.7W/kg.

Example 3

The molten steel composition of ultra-thin grain-oriented silicon steel sheet is C 0.08%, Si 3.4%, Mn 0.30%, S0.04%, Als 0.05%, N 0.007%, Cu 0.6%, Sn 0.2%, O<0.004%, P<0.01%, the balance is Fe; magnetic induction B ₈ is 1.83T, iron loss P _10/400 is 7.1 W/kg, P _10/1000 is 27.2W/kg, thickness 0.15mm;

Manufacturing method is the same as embodiment 1, and difference is:

(1) Molten steel for smelting, with the same composition as above;

(2) The superheat degree on the upper surface of the molten pool is 70°C, and the molten steel is exported at a speed of 20m/min;

(3) The cast strip is cooled at a rate of 100 °C/s, the hot rolling start temperature is 1150 °C, the reduction rate is 50%, and the hot rolling is cooled at a rate of 100 °C/s;

(4) The normalization treatment temperature is 1150°C, the time is 1min, and the normalization treatment cooling rate is 50°C/s;

(5) The first cold rolling reduction rate is 70%; the intermediate annealing temperature is 1100 ° C, and the time is 3 minutes;

(6) The reduction rate of the secondary cold rolling is 70%; the decarburization annealing temperature is 900°C, and the time is 3min;

(7) Heat the plate coated with annealing release agent to 800±10°C, then raise the temperature to 1200±10°C at a rate of 30°C/h to complete high-temperature annealing, and then keep it at 1200±10°C for 22 hours to complete the purification annealing;

Molten steel with different components was used for comparative experiments in the above manner, and the components were C 0.07%, Si 2.9%, Mn 0.032%, S 0.06%, Als 0.11%, N 0.02%, Cu 0.3%, O<0.004%, P<0.01%, the balance is Fe; the magnetic induction B ₈ of the obtained silicon steel plate is 1.67T, the iron loss P _10/400 is 10.7W/kg, and the P _10/1000 is 30.9 W/kg.

Claims (1)

1. A short flow manufacturing method of an ultra-thin oriented silicon steel plate, characterized in that it is carried out in the following steps: (1) Smelting molten steel, the components of molten steel are: C 0.002~0.08%, Si 2.8~3.4%, Mn 0.05~0.30%, S 0.015~0.04%, Als 0.005~0.05%, N 0.003~0.010%, Cu 0~0.6%, Sn 0~0.2%, O<0.004%, P<0.01%, the balance is Fe; (2) Using a twin-roll strip continuous casting device, the molten steel is poured through the tundish into a cavity composed of two crystallization rollers and two side sealing plates to form a molten pool, and the upper surface superheat of the molten pool is controlled to be 10~70°C , the molten steel in the molten pool solidifies with the rotation of the crystallization roller and is exported at a speed of 20-60m/min to obtain a cast strip; the length of the contact arc between the molten steel in the molten pool and the surface of the crystallization roller is 100-250mm, and the height of the molten pool is 80~220mm; (3) The cast strip is cooled by the cooling unit at a speed of 20-100°C/s and then hot-rolled. The rolling start temperature is 900-1150°C, the hot-rolling reduction rate is 15-50%, and the final rolling temperature is above 800°C , after hot rolling, cool at a rate of 20~100°C/s to below 650°C and coil to obtain hot rolled coils; (4) Normalize the hot-rolled coil at a temperature of 850-1150°C for 1-10 minutes. After the normalization, perform controlled cooling at a cooling rate of 5-50°C/s, and cool to normal temperature to obtain a normalized sheet ; (5) Pickle the normalized plate to remove the surface oxide scale, then conduct a cold rolling, the reduction rate of the first cold rolling is 40~70%; then perform intermediate annealing, the temperature is 800~1100°C, and the time is 3~10min, Obtain an intermediate annealing plate; the atmosphere during the intermediate annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 50%, and the dew point of the mixed gas is 20~45°C; (6) Pickling the intermediate annealed sheet to remove the surface oxide scale, and then performing secondary cold rolling, the reduction rate of the secondary cold rolling is 70~98%; then performing decarburization annealing, the temperature is 800~900°C, and the time is 3 ~10min; the atmosphere during decarburization annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 50%, and the dew point of the mixed gas is 20~45°C; (7) Coating an annealing separator on the surface of the plate after decarburization annealing; (8) Heat the plate coated with annealing release agent to 800±10°C, then raise the temperature to 1200±10°C at a rate of 10~30°C/h to complete high-temperature annealing, and then keep it at 1200±10°C for at least 20 hours to complete the purification Annealing, and finally uncoiling, flat stretching annealing and insulating layer coating to make an ultra-thin oriented silicon steel plate with a thickness of 0.05~0.15mm and a magnetic induction B8 of 1.72~ _1.83T ; the iron loss of the steel plate is P _{10 /400} is 6.6~8.1W/kg, P _10/1000 is 19.2~27.2W/kg; the atmosphere during high temperature annealing is a mixed atmosphere of hydrogen and nitrogen, the volume percentage of hydrogen is 75%, and the atmosphere during purification annealing for hydrogen atmosphere.