CN1023024C - Production of silicon steel with proper structure of various sizes of crystal grains by use of pre-ageing method - Google Patents

Abstract

The present invention relates to the production of silicon steel prepared from large and small crystal grains with a preageing method. Strip steel processed through smelting, pouring, hot rolling and normalizing slow cooling through a technology of general cold rolling oriented silicon steel with low iron loss and high magnetic induction is used as a raw material. Before the cold rolling, the preageing treatment of the strip steel is maintained for more than 5 seconds and less than 10 hours at 80 to 350 DEG C, the processes of ageing-cold rolling-ageing-cold rolling-ageing, etc. are formed, and the oriented silicon steel with the finished product thickness, low iron loss and high magnetic induction is obtained, and the silicon steel is prepared from large and small crystal grains. The technology of the present invention is simple, and therefore, all silicon steel plants having ageing rolling facilities can carry out the technology, and the produced silicon steel is especially suitable for making large-sized transformers and electrical machines.

Description

Production of silicon steel with proper structure of various sizes of crystal grains by use of pre-ageing method

The present invention relates to the oriented silicon steel of a kind of low-iron loss high-magnetic strength with the production of preageing method, CRYSTALLITE SIZES configuration, it belongs to the silicon steel production method.

The cold-rolled orientation silicon steel sheet is a material of making iron core such as high-power transformer, and the good more power consumption of magnetic is fewer, and volume is littler, and weight is lighter, and longer and transformer cooling oil of life-span is more economized, and current energy shortage is pursued high magnetic and seemed more urgent.

Before the present invention, (contriver: Song Benwenfu) " cold rolling process of the high magnetic effect orientating-sensitive sheet of characteristic good " (spy opens clear 50-16610) just like the Nippon Steel application, this method is: hot rolling raw material plate-cold rolling-timeliness-cold rolling-timeliness ... cold rolling (final thickness of slab), they think the technology that cold rolling and timeliness is arranged in pairs or groups, can further improve the magnetic of finished product, but lay special stress on: if before cold rolling beginning, carry out ageing treatment, finished product magnetic is worsened, must avoid.Its weak point is iron loss＞1.05W/Kg, and iron loss is too high.Also on steel disc, constitute 1.96～11.77Pa unrelieved stress with tension film below 0.25 millimeter in that sheet is thick just like (contriver: rock mountain strong third-class) " low iron loss single orientation silicon steel plate and manufacture method thereof " (spy opens clear 60-59045) this method of Nippon Steel application, obtained to have the crystal grain of specific dimensions and distribution, its weak point is to possess the low iron loss that 5 conditions that its proposes could realize silicon steel simultaneously.

The objective of the invention is to adopt the low silicon steel of magnetic strength height, iron loss of preageing method production CRYSTALLITE SIZES configuration, overcome the deficiency of " must possess the CRYSTALLITE SIZES configuration that 5 conditions could realize the low-iron loss high-magnetic strength of silicon steel simultaneously ", also corrected above-mentioned " carrying out preageing before once cold rolling can make magnetic worsen " prejudice.

Purpose of the present invention can reach by following measure: promptly make raw material with the band steel of the smelting of common high-magnetic induction, low-iron loss cold-rolled orientation silicon steel technology, casting, hot rolling and normalizing slow cooling; silicon steel through cold-rolling practice production; it is characterized in that cold rolling preceding maintenance was less than 10 hours ageing treatment in advance more than 5 seconds, constitute timeliness-cold rolling-timeliness-cold rolling-timeliness ... be rolled to final finished thickness.

Ageing treatment is that N, C atom precipitation between cold rolling pass accumulate in microdefect places such as dislocation between passage, form cottrel air mass pinning dislocation, make the deformation difficulty, produced the special deformed microstructure " striation " that helps secondary recrystallization, thereby formed the secondary recrystallization core, macrograin is diminished.It is to form the cottrel air mass on the hot rolled strip that microdefect is few slightly before cold rolling that preageing is handled, and when being with steel after the ageing treatment between cold rolling and passage, has then produced the fabulous non-axle layout type crystal grain that waits of size configure.The silicon steel of this CRYSTALLITE SIZES configuration with IPS automated image analysis system measure as the spy open clear 60-59045 rock mountain be good for the pointed equivalent diameter of third-class patent of invention (

$\mathrm{R\; =}\sqrt{\frac{A}{\pi }}$

; D=2R, A is an area in the formula, R is a radius, D is an equivalent diameter) the little number of die of 2 millimeters of D ∠ accounts for the 15-70% of total number of die, mean distance ND=2.0～8.0 between little crystal grain closes on millimeter.On different band steel raw materials control reasonably in advance aging temp and time carry out interior thickness immediately before the timeliness of each passage rolling, can obtain little crystal grain and be 45～60%, mean distance is the layout type crystal grain of 5 millimeters optimum regime.

Keep during ageing treatment in advance can causing solid solution N, C atom whole precipitations cold rolling before to separate out more than 10 hours, subsequently the rolling no N of timeliness, C atom are separated out, thereby magnetic degenerates, be kept to less than and cause for 5 seconds solid solution N, C atom precipitation before cold rolling to separate out deficiency again, do not form the splendid layout type crystal grain of size configure.

When timeliness was rolling, the band steel was by " middle thickness of slab timeliness " cold rolling (spy opens clear 50-16610), i.e. first passage ageing treatment not, produce than cold rolling at room temperature little and than this patent big wait axle type crystal grain, cause that iron loss raises.

Carry out " the interior thickness timeliness is rolling " under the situation that band steel preheating temperature cold rolling before is low and warm up time short or the timeliness rolling pass is few, can only obtain the big axle type crystal grain that waits, then iron loss rising, magnetic strength are also low.

Below the present invention is described further in conjunction with the accompanying drawings.

Fig. 1 is the photo with the size configure crystal grain under 3 times of IPS method (terminal band computer) measurement;

The photo that Fig. 2 distributes for the little crystal grain after using IPS method (terminal band computer) with big crystal grain cancellation among Fig. 1 (2 millimeters of D equivalence ∠).

With embodiment the present invention is described in detail below:

Embodiment one:

With being by weight percentage: Si 3.16; Mn 0.09; S 0.028; Al _(sol)0.030; N ₂0.0080; Sn 0.09; Cu 0.096; Mo 0.024 surplus be Fe and inevitably the continuously cast bloom of C, P become 2.2 mm thick band steel in 80 ℃ of water, be incubated 70 minutes at 1380 ℃ of following heating rollings to carry out the preageing processing, be heated to 250 ℃ of insulations 5 minutes after being cold-rolled to 1.5 millimeters, 1.15 millimeters, 0.85 millimeter and 0.55 millimeter then respectively, 0.55 not reheat and insulation below the millimeter, roll into 0.30 millimeter or other finished product thickness continuously, not being coated with the preceding magnetic of tension film is W17/50:0.96 watt/kilogram, B ₁₀: 1.949 teslas, less than 2 millimeters total number of die 53% of grains constitute, 4.5 millimeters of the contiguous average headways of little crystal grain; Average 7 of every square centimeter little crystal grain number.

Embodiment two:

With being by weight percentage: Si 3.2; Mn 0.09; S 0.029; Al _(sol)0.029; N ₂0.0090; Sn 0.07; Cu0.096; Mo0.044; Surplus be Fe and inevitably the continuously cast bloom of C, P through being rolled into 2.2 mm thick band steel; heating is 2.5 minutes in 1120 ℃ protective atmosphere; with 3 ℃/second speed slowly cool to 800 ℃ immerse in 100 ℃ the water again, the pickling de-scaling; before cold rolling in advance the Heating temperature of ageing treatment be 250 ℃ of insulations 6 seconds, and carry out ageing treatment rolling of each passage respectively.Not being coated with and recording magnetic before the tension film is W17/50:0.94 watt/kilogram, B ₁₀: 1.944 teslas, about 55% less than 2 millimeters total number of die of grains constitute, about 5.5 millimeters of the contiguous average headway of little crystal grain, about 7 of every square centimeter of crystal grain number.

Embodiment three:

With containing weight percent be: Si 3.24; Mn 0.08; S 0.028; Al _(sol)0.031; N ₂0.0092; Sn 0.12; Cu 0.10; Surplus be Fe and inevitably the continuously cast bloom of C, P by the processing method hot rolling of embodiment 2, normalizing, cold rolling, continuous annealing, be coated with MgO and high temperature annealing.Not being coated with and recording magnetic before the tension film is W17/50:0.98 watt/kilogram, B ₁₀: 1.940 teslas, about 60% less than 2 millimeters total number of die of grains constitute, about 4.5 millimeters of the contiguous average headway of little crystal grain, about 9 of every square centimeter of crystal grain number.

The present invention compared with prior art has technology novelty, low, the magnetic strength advantages of higher of product iron loss, these advantages from comparative example as seen:

Comparative example one:

The present invention has adopted and novel carried out the method that preageing handles before cold rolling and produce high magnetic orientation silicon steel, has corrected the prejudice that must avoid preageing before cold rolling, obtains the non-equi-axed crystal of the high CRYSTALLITE SIZES configuration of the low magnetic strength of iron loss simultaneously.

Classification cold rolling process macrograin

The spy opens clear hot rolling-cold rolling-timeliness-cold rolling-timeliness ... cold rolling size is approximate

50-16610's (raw material thickness of slab) (final thickness of slab) is large-scale etc.

The axialite grain

Hot rolling-preageing of the present invention-cold rolling-timeliness ... cold rolling CRYSTALLITE SIZES

It is non-that (raw material thickness of slab) (final thickness of slab) disposes

Equi-axed crystal

Comparative example two:

Band steel with the smelting of generally well-known high-magnetic induction, low-iron loss cold-rolled orientation silicon steel technology, casting, hot rolling, normalizing slow cooling is made raw material; undertaken cold rolling by two kinds of methods respectively: it is rolling that (1) opens clear 50-16610 patented method by the spy: be about to 2.2 mm thick hot rolled strips and be cold-rolled to 1.5 mm thick earlier; it is rolling to carry out timeliness in each passage of 1.5 millimeters, 1.15 millimeters, 0.85 millimeter and 0.55 millimeter then, and the Heating temperature of ageing treatment is 250 ℃ of insulations 5 minutes.(2) produce by preageing facture of the present invention: promptly carry out one time ageing treatment before cold rolling earlier, all to carry out ageing treatment the same with each passage of above-mentioned said 1.5 millimeters, 1.15 millimeters, 0.85 millimeter and 0.55 millimeter for other.Two kinds of steel plates all contain TiO in 840 ℃ of continuous annealings, coating ₂MgO solution after dry, under 1210 ℃ through 20 hours high temperature annealings.Not being coated with tension film preceding magnetic and macrograin situation sees the following form:

Class is compiled the crystal grain parameter macroscopic view of 2 millimeters of magnetic D equivalence ∠

W17/50 B ₁₀The little crystal grain crystal grain of the little number of die of little number of die

The total number square centimeter ND type of alias (W/Kg) (tesla)

This 1 0.96 1.9310 50.1062% 6.3477 5.8729 size

2 0.96 1.9430 53.7698% 7.2891 5.4939 configurations

Send out 3 0.97 1.9460 53.4737% 6.8319 5.6521 non-

4 0.98 1.9300 56.7812% 8.4457 5.0192 axles such as grade

Bright 5 0.99 1.9310 49.1425% 5.4601 6.3609 crystal grain

Special 1 1.03 1.9430 31.8435% 1.5700 14.1902 diameter

Open about 10

Clear 2 1.07 1.9210 30.4527% 1.4928 13.3347～15

Millimeter

3 1.08 1.9060 33.3333% 1.6461 12.2699 etc.

Axialite

4 1.08 1.9190 28.1768% 1.1758 14.6595

50-16610

5 1.15 1.9280 32.3529% 1.2680 14.4174

Can find out from table and adopt preageing method of the present invention to produce the oriented silicon steel that silicon steel can obtain the CRYSTALLITE SIZES configuration, iron loss has obviously reduced, magnetic strength B ₁₀Also make moderate progress.

Adopt the orientation silicon steel process of preageing method production CRYSTALLITE SIZES configuration of the present invention simple, the silicon steel factory of all effective rolling facilities all can implement, and the silicon steel of being produced is specially adapted to make high-power transformer and motor.

Claims (1)

1, a kind of method with preageing method production CRYSTALLITE SIZES configuration silicon steel; band steel with the smelting of common high-magnetic induction, low-iron loss cold-rolled orientation silicon steel technology, casting, hot rolling and normalizing slow cooling is made raw material; produce silicon steel through cold-rolling practice; it is characterized in that cold rolling preceding maintenance was less than 10 hours ageing treatment in advance more than 5 seconds, constitute timeliness--cold rolling----cold rolling--timeliness of timeliness ... be rolled to final finished thickness.