JPS61124526A - Manufacture of grain oriented silicon steel sheet having good electromagnetic characteristic - Google Patents

Abstract

PURPOSE:To improve magnetic characteristic and production efficiency, by regulating biting of steel sheets against rolls of every respective stands, to prescribed angles, at the final cold rolling of Si bearing steel by tandem rolling mill. CONSTITUTION:One time or 2 times cold rollings contg. intermediate annealing are applied to Si bearing steel hot rolled plate. Thereat, the final cold rolling is carried out at >=50% draft by tandem rolling mill. Biting angle alpha of steel sheet against rolls at each stand is regulated to >=0.02 deg.. Next, decarbonization annealing, final finishing annealing are applied to obtain the titled steel sheet having main orientation of (110) [001].

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for manufacturing unidirectional silicon steel sheets with good magnetic properties, and in particular, to an effective improvement of magnetic properties as well as an increase in production efficiency. This is what we are trying to achieve.

(Prior Art) Unidirectional silicon steel sheets are mainly used as iron cores for transformers and other electrical equipment, and are required to have good excitation characteristics and iron loss characteristics. In particular, recently, social demands for energy conservation and resource conservation have become stronger and stronger, and there has been a long-awaited demand for low iron loss materials that place particular emphasis on power loss when electrical equipment is used. In order to meet such demands, various measures have recently been taken, such as making the product plate thinner than before, making the secondary grain size finer, and applying techniques for refining the magnetic domain width. For this reason, the manufacturing process of silicon steel sheets has become increasingly complicated, and an increase in manufacturing costs due to the complexity of the process has become a problem.

By the way, conventionally, cold rolling of homogeneous silicon steel sheets
Sendzimir and 4- to 6-high reverse rolling mills are used, and tandem rolling, which is continuous rolling in one direction, is not suitable, especially when producing grain-oriented silicon steel sheets with high magnetic flux density. was.

This is because tandem rolling cannot provide the excellent magnetic properties of reverse rolling due to the difference in texture after cold rolling recrystallization.In addition, several methods have been recently proposed to improve electromagnetic properties. One of the reasons is that it is difficult to use inter-pass aging processing. For example, the special public official court 54-2918
Publication No. 2 proposes holding the temperature in the temperature range of 300 to 600°C for 1 to 30 seconds when performing 81 to 95% hard cold rolling in multiple passes, but since this is done by tandem rolling, In addition to requiring the installation of heating equipment in the middle,
Rolling must be performed at extremely low speeds, and the efficient rolling that is a feature of tandem rolling cannot be utilized. Also, JP-A-57
Publication No. 4306 proposes installing an inductor to preheat the electromagnetic steel sheet on the entrance side of the cold rolling mill.
Cold rolling of high-silicon steel sheets is based on the assumption that a reverse rolling mill is used, and interpass aging treatment in tandem rolling is not considered.

(Problems to be Solved by the Invention) As described above, in the past, the manufacturing process has become complicated, resulting in an increase in manufacturing costs, and there have been problems in that the production efficiency is low.

This invention was developed in view of the recent circumstances as described above, and not only meets the demand for improving the performance of silicon steel sheets, but also efficiently performs cold rolling using a tandem rolling mill. The object of the present invention is to propose an advantageous manufacturing method for silicon steel sheets that can also reduce manufacturing costs through such efficient production.

(Means for Solving the Problems) In order to achieve the above object, the inventors have conducted extensive research into improving magnetic properties through tandem rolling, and have found that By controlling the biting angle with respect to the rolling rolls, the texture after cold rolling recrystallization can be advantageously improved, resulting in high magnetic flux density with excellent electromagnetic properties without special treatment such as interpass aging. It was discovered that a unidirectional silicon steel sheet could be obtained, and this invention was completed.

In other words, this invention involves cold rolling a silicon-containing hot-rolled steel sheet once or twice including intermediate annealing to obtain a predetermined product thickness, followed by decarburization annealing and final finish annealing. In the method for manufacturing a unidirectional silicon steel sheet whose main orientation is (110) (001), the final cold rolling is performed by
A unidirectional silicone material with good electromagnetic properties, in which the biting angle α of the steel plate with respect to the rolling roll for each stand is 0.02° or more when rolling is carried out with a tandem rolling mill at a reduction rate of 50% or more. This is a method for manufacturing steel plates.

In this invention, the reason why the angle of engagement of the steel plate with respect to the rolling rolls of each rolling stand is regulated within the above range is based on the experimental results described below.

Si: 3.40wt% (hereinafter simply expressed as %), C
:o, oso%, Mn: 0.08%, Se:
0.025% and Sb: 0.030%, a silicon steel hot-rolled steel sheet with a thickness of 3.0 was first cold-rolled to 0.03%.
．． The thickness was set to 80 to 0.90 mm, and then heated to 1000°C for 1
After performing intermediate annealing for 0.0 min, secondary cold rolling was performed.
Finished with a product board thickness of 3mm. This secondary cold rolling was carried out using a tandem rolling mill, and at that time, the rolling reduction distribution (2 to 1
The bite angle was varied by changing the roll diameter (150 to 600 u"). These steel plates were then subjected to decarburization annealing and high-temperature box annealing to produce the final product. .

of each product obtained! Figure 1 shows the results of an investigation into the relationship between magnetic properties (magnetic flux density, iron loss) and the bite angle of each stand during secondary cold rolling. Here, the bite angle defined by the symbol α shown in FIG. Find the angle of entry.

As is clear from Figure 1, the biting angle α is 0.02
By setting it to 1.90 T or more, a unidirectional silicon steel plate with low core loss can be obtained.

In addition, in this invention, the rolling reduction rate of the final cold rolling is 50%.
The reason for this is that if the rolling reduction is less than this, sufficient development of the Goss orientation will not be achieved after the final finish annealing.

(Function) The preferred composition range of the material in this invention is as follows.

C: 0.01-0.08% Regarding the content of C, the above range allows for the presence of an appropriate amount of Goss-oriented grains in the cold-rolled recrystallized texture, and facilitates the growth of Goss grains in secondary recrystallization. This is because it is convenient for forming a matrix.

Si: 2.0 to 4.0% The lower limit of St mentioned above is determined as the amount that allows dulling at high temperatures without damaging the texture due to transformation, while the upper limit can be set to about 4% due to the limit of workability. desirable.

Other inhibitors include sulfides (e.g. Mn5)
, Se oxide (for example, Mn5e), and nitride (for example, A j2 N, B N), etc., and the range is not particularly limited, but preferably S, S
For e, AJ, B, etc., it is preferable to set the amount to about 0.005 to 0.10%, whether added alone or in combination.

Now, the slab containing the above-mentioned components is first heated to a high temperature of 1250°C or higher that can dissolve the inhibitor, and then hot-rolled into a hot-rolled plate having a thickness of 1.5 to 3.5M. Next, cold rolling is performed, but in the case of one-time cold rolling method, the rolling temperature is 900.
After homogenizing annealing at ~1120° C. for 0.5 to 10 a+in, the sheet is cold rolled to a final thickness of 0.15 to 0.35 m. In addition, in the case of two-time cold rolling, after the first cold rolling has an intermediate thickness of 0.4 to 1.5 w@
After an intermediate annealing of 0.15 to 0, the second cold rolling
．． Finish to a product board thickness of 35mm.

In this invention, in the cold rolling process, the final cold rolling is carried out continuously using a tandem rolling mill under the condition of a total rolling reduction of 50% or more, and the biting angle α of the steel plate with respect to the rolling rolls in each stand is Both are 0.
The angle is set to 02° or more. Here, since the biting angle α is determined by the roll diameter and the rolling distribution, it is important to appropriately select these so that α≧0.02° in any stand.

The cold-rolled sheet thus obtained is then decarburized annealed in wet hydrogen at 750 to 850°C, then an annealing separator is applied to the surface of the steel sheet, and then secondary recrystallization and purification are performed at a high temperature of 1100°C or higher. The product is then subjected to box annealing. After this, if necessary, the surface can be coated with a top coat to produce a product.

(Example) Example I C: 0.040%, Si: 3.20%, M
A continuously cast silicon steel slab having a composition containing n: 0.075%, S: 0.020% and Sb: 0.030% was heated at 1330° C. for 3 hours, and then hot rolled. A hot-rolled sheet with On+ thickness was obtained. Then, after finishing it to an intermediate thickness of 0.6 (b-) by primary cold rolling, NzHz
After performing an intermediate annealing of 3 ml at 0° C. in a mixed gas, a secondary cold rolling was performed using a 5-stand tandem rolling mill to obtain a cold-rolled sheet with a thickness of 0.23 m. In this secondary cold rolling, two types of rolling rolls with roll diameters of 200 mm and 400 m were used, and the rolling was carried out under conditions in which the rolling reduction distribution was varied as shown in Table 1.

After that, each cold-rolled plate was heated at 800°C in wet hydrogen for 5 m1n.
Decarburization annealing was performed, and then an annealing separation agent containing MgO as a main component was applied, followed by final annealing at 1200° C. for 10 hours in hydrogen.

Table 1 also shows the results of investigating the magnetic properties of each product board thus obtained.

As is clear from the table, when the bite angle of each stand is 0.02 @ or more (condition, 3
．． 5), particularly excellent magnetic properties were obtained.

Example 2 C: 0.052%, Si: 3.0
8%, Mn: 0.080%.

S: 0.022%, A, /: 0.026%
A continuously cast silicon steel slab having a composition containing 0.0075% of N was heated at 1330° C. for 3 hours and then hot rolled into a hot rolled plate with a thickness of 2.0 wm. Then 112
After homogenizing annealing at 0° C. and 2 ml, it was cold rolled using a 5-stand tandem rolling mill under the conditions shown in Table 2, and finished to a thickness of 0.30 mm.

After that, decarburization annealing was performed at 800° C. + 5 ml in wet hydrogen, an annealing separator containing MgO as a main component was applied to the surface of the steel sheet, and finish annealing was performed at 1200° C. for 10 hours in hydrogen.

Table 2 also shows the results of investigating the magnetic properties of the product board thus obtained.

As is clear from the same table, when the bite angle is 0.02° or more in any pass (condition 7.8), the magnetic properties are improved.

(Effects of the Invention) Thus, according to the present invention, magnetic properties can be improved and production efficiency can be improved by simply controlling the bite angle of each stand of a tandem rolling mill in the final cold rolling process of cold rolling. As a result, this can be achieved effectively as well as reducing manufacturing costs.

[Brief Description of the Drawings] Fig. 1 shows that the biting angle α of each stand of the tandem rolling mill in the final cold rolling is the iron loss w+tzs of the final product. FIG. 2 is an explanatory diagram of the biting angle α. Procedural Amendment January 18, 1985 Patent Application No. 243466 2 Title of Invention: A method for producing unidirectional silicon steel sheets with good electromagnetic properties Relationship Patent 1 fliiff person (125) Kawasaki Steel Corporation L#4aiF 4aiF 14-15 row (F) r Coco"C' jh: H of the difference in plate thickness between the entrance and exit sides of each stand
"Here, Δh: Difference in board thickness between entrance and exit sides of each stand."
Correct to. 1 Correct Figure 2 as shown in the attached sheet.

Claims (1)

[Claims] 1. Hot-rolled silicon-containing steel sheet subjected to one or intermediate annealing 2.
After the product is cold-rolled twice to obtain a predetermined thickness, it is decarburized and then subjected to final finish annealing (11
0) In the method for manufacturing unidirectional silicon steel sheets with the main orientation being [001], when the final cold rolling is performed with a tandem rolling mill at a reduction rate of 50% or more, the steel sheet of each stand is Both biting angles α are 0.
．． A method for producing a unidirectional silicon steel sheet with good electromagnetic properties, characterized in that the angle is 02° or more.