DE1259368B - Process for the production of silicon steel sheets with (100) [001] texture - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C21d

German class: 18 c-1/78

Number:
File number:
Registration date:
Display day:

1259 368
O7006VI a / 18c
October 8, 1959
January 25, 1968

The invention relates to a method for producing silicon steel sheets with a (100) [001] texture.

It is the aim of the invention to provide an economical process for the production of doubly oriented To create silicon steel sheets that have good orientation properties in two mutually perpendicular Have directions in the rolling plane and also have low overall magnetic loss exhibit.

A silicon steel sheet which is easily magnetizable in one direction is known.

There are also known methods for producing silicon steel plates, in which a magnetic Orientation in two perpendicularly crossing directions in the rolled surface Rolling process of iron-silicon alloys in intersecting directions is to be achieved.

According to this known method, an iron-silicon alloy with a silicon content is produced Cold rolled up to 5% in two intersecting directions, whereupon the rolled material is at one temperature is annealed from 600 to 1000 ° C.

Another known method involves multiple cold rolling with intermediate annealing and a subsequent final annealing, the last Cold rolling takes place in directions deviating from the original rolling direction by 45 and 90 °. These known methods are very different from the method according to the invention It is essential that according to the invention a material is used which has a small proportion of aluminum in addition to the alloying elements common in silicon steel.

Other known methods of making oriented silicon steel sheets are also used a raw material that does not contain aluminum.

It was previously believed that aluminum was an undesirable impurity in oriented Is silicon steel sheets, and the addition of aluminum has been made, as from publications of the Experts can be found, as far as possible prevented.

In contrast, it has been found that the addition of aluminum has a completely surprising new effect namely, a great improvement in magnetic properties. So z. B. the Steel sheets produced according to the invention are excellently magnetized even in weak magnetic fields will.

According to the invention, these advantages are achieved through the joint application of the following measures:

Method of manufacture

of silicon steel sheets with (100) [001] texture

Applicant:

Yawate Iron & Steel Company Limited, Tokyo

Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. E. Assmann

and Dipl.-Chem. Dr. R. Koenigsberger,

Patent Attorneys, 8000 Munich 2, Bräuhausstr. 4th

Named as inventor:

Satoru Taguchi,

Akira Sakakura, Yawata City,

Fukuoka Prefecture;

Takashi Yasunari, Tobata City,

Fukuoka Prefecture (Japan)

Claimed priority:

Japan 8 October 1958 (28 745)

a) a silicon steel with 2.0 to 4.0% silicon, 0.02 to 0.06% C, 0.01 to 0.05% aluminum, Remainder iron, is hot rolled to a thickness of 0.7 to 13 mm;

b) the hot-rolled sheet is pickled and cold-rolled with a degree of deformation of 30 to 60%;

c) the cold-rolled sheet is then at a right angle + 20 ° to the previous rolling direction cold-rolled again to a degree of deformation of 20 to 50%;

d) this cross-rolled sheet is then intermediate annealed at 850 to 1200 ° C .;

e) the intermediate annealed sheet is then rolled to the finished size in one of the two cold rolling directions cold-rolled with a degree of deformation of 50 to 84%;

f) the finish-rolled sheet is finally annealed at 1000 to 1300 ° C. for 5 to 40 hours.

The aluminum contained in a hot-rolled material consists of acid-soluble and acid-

709 720/351

insoluble aluminum, of which the acid-soluble is particularly important. In the description is however, reference is made to the total aluminum content.

Fig. 1 shows the dependence of the magnetic Total loss and magnetic induction of the material after the last heat treatment on the aluminum content of the hot rolled material, being six different hot rolled Silicon steels (plates of 2 mm thickness) with an analysis shown in Table 1 with reduction their thickness by about 30%, cold rolled in the hot rolling direction, then reducing the Thickness cold rolled by about 30% in a direction approximately perpendicular to the hot rolling direction, then treated warm for about 5 hours at a maximum temperature of 1100 ° C, then again given the final heat treatment while reducing the thickness by 70% in a direction perpendicular to the hot rolling direction, while im In contrast, similar results for common silicon steel, either less than 0.010% Aluminum or contains more than 0.050% aluminum, despite the same treatment, not achieved will. This difference shows very clearly the advantages of the invention.

The thickness of the hot rolled steel is of great importance to a double-oriented silicon steel sheet to manufacture. The starting material should be 5 to 30 times as thick as the desired one End product.

Accordingly, the thickness of the raw material becomes in the range of 0.7 to 13 mm and preferably chosen about 3 mm.

The hot-rolled silicon steel is pickled in the usual manner to remove the mill scale. The deformation caused by the cold rolling in mutually perpendicular directions as a function of

g g g gg

rolled and then finally 15 hours with a 20 the combination of the rolling directions is of the greatest Final annealing temperature of 1150 ° C. Meaning. According to the invention, a deformation

F i g. 2 shows the influence of the temperature of the intermediate 4 bi 80 b b di V

annealing on the magnetic properties of the sheet metal produced according to the invention.

g gg g

preferred by 44 to 80%, the deformation during the first cold rolling in one direction 30 to 60% and in the case of the second cold rolling in the

gg g

F i g. 3 shows the dependence of the magnetic 25 other direction perpendicular to the first 20 to

Induction from that caused by cold rolling Reduction in thickness of the sheet metal produced according to the invention.

In Figs. 1, 2 and 3, the solid curve drawn by the black dots relates to the last rolling direction, the dashed curve drawn through the circles to the right-angled Direction to it.

Table 1

example Add
Si immense
Al tion in%
all in all
Al soluble Magnetic
properties
(Epstein)
BIO jW15 / 50 1.99
1.87 A. 3.05 0.005 0.002 15.200
15,250 1.42
1.40 B. 3.01 0.015 0.010 17,150
17,400 1.04
1.09 C. 3.11 0.021 0.016 18,050
17,950 0.99
1.01 D. 3.02 0.026 0.020 18,250
18,150 1.19
1.26 E. 3.06 0.041 0.032 17,800
17,700 1.47
1.55 F. 3.01 0.065 0.051 17,100
17,000

Remarks:

1. W15 / 50 is the magnetic loss of the iron core at 15,000 Gauss, which is measured at a frequency of 50 Hz and whose unit is watts per kilogram.

2. B 10 denotes the magnetic induction at 10 Oersteds, the unit of which is 1 Gauss.

3. In the column of the magnetic properties in Table 1, the upper value represents the measurement result along the last rolling direction and the lower value represents the measurement result along the direction at right angles to it.

As can be clearly seen from Table 1, good orientations are in the two cold rolling directions and a low total core magnetic loss for the hot rolled silicon steel material according to FIG 50%.

If the most favorable thickness of 3 mm is used, the deformation is preferably 40% in each direction. The size of the angle that the direction of the second cold rolling with the direction of the first Cold rolling has a significant impact on the magnetic properties of the product. According to the invention there is an angle of approximately 90 ° between the various reciprocal Rolling directions preferred. The more this angle deviates from 90 °, the worse the axis easier magnetization (001) formed in two directions. However, it was found that one Deviation of the intersecting directions within the range of ± 20 ° from the right angle is permissible.

The hot-rolled silicon steel strip is first pickled, then cold-rolled, and then into a number cut from pieces of predetermined length, whereupon the ends of the pieces are welded together to form a new steel strip whose longitudinal direction changes the first cold rolling direction crosses approximately 90 + 20 °, after which the second cold rolling is carried out and the strip is further treated will. The welding together can also after the second cold rolling, the intermediate annealing or the last cold rolling to be carried out. However, the welding together is not in every case necessary.

An intermediate furnace or box for heat treatment for the iron-silicon sheet or -Belt, the thickness of which was reduced to an average level by the two cold rolling in two mutually intersecting Directions has been decreased has a significant influence on the recrystallization structure as a result of the heat treatment. According to the invention, the maximum continuous temperature should preferably are in the range from 850 to 1200 ° C.

In Fig. Figure 2 is a graph of the effect of intermediate anneal temperature on the magnetic Properties of the material produced by the method according to the invention shown, this Material made from a hot-rolled silicon steel

_30th

35

40

45

50

55

60

with a content of 3.02% Si and 0.026% Al is first cold-rolled in the hot rolling direction with a reduction in thickness of about 30%, then cold-rolled again with a reduction in thickness of about 30% approximately at right angles to the previous direction, then about for 5 hours, calcined at a temperature of 800 to 1200 ° C, then under reduction of the thickness by 70% for the last time cold rolled in the second cold rolling direction, and then to final 15 hours long at a temperature of 1150 ⁰ C.

As shown in FIG. 2 is seen, the heat treatment so as to effect more favorable, the higher the annealing temperature, but this effect decreases at a temperature above about 1000 ⁰ C. The magnetic properties also decrease below 850 ° C.

The deformation by the final cold rolling is important to the double-oriented silicon steel sheet and the direction in which this final cold rolling is carried out is said to be about the same Direction like one of the two intersecting directions of the first two cold rolling. From the from an economic point of view, it is most practical to to choose the second cold rolling direction.

In Fig. 3 graphically shows the dependence of the magnetic induction on the deformation by the cold rolling of the sheet produced according to the invention, the starting material being a hot-rolled silicon steel of 3 mm thickness with a content of 3.05% Si and 0.034% Al, which is initially deformed by 40% is cold-rolled in the hot-rolling direction, then cold-rolled a second time by 40% perpendicular to the first-mentioned direction, then ^{annealed for 5 hours at a maximum maintained temperature of 1100 °} C., then a last time with deformation of about 19 to 84% in the second cold rolling direction is cold rolled and finally annealed for 15 hours at a temperature of 115O ^{0 C.} The results show that the deformation of the starch by the final cold rolling is suitably about 50 to 84%, most preferably about 70%.

In order to obtain a double-oriented silicon steel sheet which has a low total magnetic loss, it is necessary ^{to anneal the steel for at least 5 hours at a temperature of over 1000 °} C. in a neutral or reducing atmosphere. Complete crystal growth cannot be achieved by annealing at a lower temperature of 1000 ^{° C.} On the other hand, annealing over 1300 ^° C. or longer than 40 hours, in spite of this increased temperature or this long period of time, does not achieve a more favorable effect, but disadvantages are not found either.

It goes without saying that the carbon content of the product should be as low as possible after the last heat treatment. In particular is a content of less than 0.005% carbon is very desirable.

A silicon steel used for the method of the present invention can usually Contain 0.02 to 0.06% carbon. Therefore the steel should be decarburization annealed when the Carbon content was not reduced to the desired level by the two anneals. For this known methods can be used. Suitable is z. B. a heat treatment with the existing one Mill scale at a temperature of 650 to 900 ° C and a short tempering in an atmosphere, which has a little moisture, at a temperature of 750 to 950 ° C.

example 1

A hot-rolled silicon steel 2 mm thick and containing 3.06% Si and 0.03% Al is cold rolled 30% in one direction. On that

ίο it is cold-rolled again in one direction approximately perpendicular to it by 30% to an average dimension of 0.98 mm and annealed for 10 hours at a temperature of 950 ° C.
This steel is then cold-rolled in the second cold-rolling direction by 68% to a final dimension of 0.31 mm, and then finally annealed at a temperature of 1200 ° C. for 20 hours. This product was sampled along the direction in which it was last cold rolled and along the direction

ao tion taken perpendicular to it and the magnetic properties checked. The result obtained is following:

Last cold rolling direction ..
Direction perpendicular to it ..

BIO

17800 gauss
17650 Gauss

W15 / 50

1.26 W / kg 1.34 W / kg

The above values indicate excellent cube texture.

Example 2

The same hot-rolled silicon steel as in Example 1 was decarburization annealed with mill scale for 5 hours at a temperature of 68O ⁰ C, then cold-rolled by 30% in one direction, then in a direction approximately perpendicular to this by 30% to an average dimension of 0, 98 mm again cold rolled and annealed for 5 hours at a temperature of 1100 ° C in a furnace.

This steel is then cold by 70% in the second cold rolling direction to a final dimension of 0.30 mm rolled out and finally annealed for 15 hours at a temperature of 1150 ° C.

This product became an Epstein sample along the last rolling direction and along the direction taken perpendicular to it and measured the magnetic properties. The result is this:

Last cold rolling direction ..
Direction perpendicular to it ..

BIO

18250 Gauss
18050 Gauss

W15 / 50

0.99 W / kg 1.04 W / kg

The above result shows an excellent cube texture.

Example 3

A hot rolled silicon steel 3.0 mm thick containing 3.05% Si and 0.034% Al becomes a silicon steel sheet with a reduction in thickness of 40% in the hot rolling direction 1.8 mm thick cold rolled.

Thereafter, this tape is cut into a number of pieces of a predetermined length. These pieces will be with their ends welded together to form a band, the longitudinal direction of which is perpendicular to

first cold rolling direction is directed. This new band is increased by 40% to a mean level of 1.08 mm cold rolled. After annealing for 10 hours at a temperature of 1100 ° C, it becomes it is cold-rolled to the final dimension in its longitudinal direction with a degree of deformation of 72%, then annealed at a temperature of 800 ° C for 3 minutes in a moist hydrogen atmosphere to remove the carbon, and finally at a temperature of 1200 ° C for 20 hours glows to maintain the magnetic properties. An Epstein sample was made from this product taken in the longitudinal direction and in a direction perpendicular thereto and the magnetic properties checked. The result is this:

Last cold rolling direction ..
Direction perpendicular to it ..

BIO

18340 Gauss
18150 Gauss

W15 / 50

0.98 W / kg 1.05 W / kg

The above values show that a double-oriented silicon steel sheet with a good cube texture was achieved.

Claims (1)

Claim: "Process for the production of silicon steel sheets with (100) [001] text no., Characterized by the common application the following measures: a) a silicon steel with 2.0 to 4.0% silicon, 0.02 to 0.06% C, 0.01 to 0.05% aluminum, Remainder iron, is hot rolled to a thickness of 0.7 to 13 mm; b) the hot-rolled sheet is pickled and with a degree of deformation of 30 to 60% cold rolled; c) the cold-rolled sheet is then at a right angle ± 20 ° to the previous rolling direction cold-rolled again with a degree of deformation of 20 to 50%; d) this cross-rolled sheet is then intermediate annealed at 850 to 1200 ° C .; e) the intermediate annealed sheet is then placed in one of the two to the final size Cold rolling directions with a degree of deformation of 50 to 84% cold rolled; f) the finish-rolled sheet is finally annealed at 1000 to 1300 ° C. for 5 to 40 hours. Considered publications: German Patent Nos. 689 986, 741077; "Chemisches Zentralblatt", 1958, pp. 2861/2862; "Handbuch der Sonderstahlkunde" by E. Houdremont, 1956, H. Volume, pp. 1183, 1224 and 1225; "Archives for the iron and steel industry", 1958, pp. 423 to 432. 1 sheet of drawings 709 720/351 1.68 © Bundesdruckerei Berlin