JPS58171527A - Manufacture of low-grade electrical steel sheet - Google Patents

Abstract

PURPOSE:To inexpensively manufacture a superior low-grade electrical steel sheet, by hot-rolling a steel contg. specified percnetages of C, Mn and sol. Al at a specified finishing temp. and a specified coiling temp. and by carrying out cold rolling. CONSTITUTION:A steel consisting of 0.005-0.08% C, 0.15-0.50% Mn, 0.002- 0.080% sol. Al and the balance Fe with impurities or further contg. <=80ppm N is continuously hot-rolled at 640-860 deg.C finishing temp. and 600-760 deg.C coiling temp. Cold rolling is then carried out. Thus, an electrical steel sheet having 9- 18W/kg iron loss (W15/50) and 1.50-1.80 T magnetic flux density (B50) is obtd.

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing low-grade electrical steel sheets,
For details, see iron loss (W+sAo) 9 to 1.8 (W, /
+<p).

Magnetic flux density (B,.) 1.50 = 1. e o (T
) relates to a method for manufacturing electrical steel sheets.

As is well known, the magnetic properties of electrical steel sheets are improved by adding S1 or the like. For example, general-purpose motors used in vacuum cleaners, electric washing machines, etc. do not require motors with very good magnetic properties.

Therefore, there is currently a strong demand for inexpensive electrical steel sheets for use in such applications.

The present invention provides an excellent technology that advantageously satisfies these requirements, and its features include c.
: 0.005~0.08%, Mn: 0.15~
0.50%, 5olAl: 0.002-0.0
In continuous hot rolling steel consisting of 80% residual impurities and iron.

Finishing temperature 640-860℃, winding temperature 600-760℃
First, by a normal cold rolling process.

A method for manufacturing a low-grade electrical steel sheet, characterized in that it is a steel sheet, and C: 0.005 to O, OB%, un: 0.15 to 0.
5Q%, 5ofAe: 0.0 0 2
~0.080%, N:80ppm
Hereinafter, steel consisting of residual impurities and iron is continuously hot rolled at a finishing temperature of 640 to 860°C.

The present invention relates to a method for producing a low-grade electrical steel sheet, which is characterized in that it is processed at a rolling temperature of 600 to 760°C and then subjected to a normal cold rolling process to form a steel sheet.

That is, in the present invention, the above-mentioned steel is made into a steel billet by ingot-forming or continuous casting, and this is processed by continuous hot rolling at the above-mentioned finishing temperature and winding temperature. Then, if O: is less than 0.005%, the hardness as a steel plate cannot be obtained, and the manufacturing cost becomes high.1. O,
If it exceeds O,S%, impurities will increase,
It is not preferable because the magnetic properties, especially the core loss, are high and the properties as an electrical steel sheet are impaired.

Regarding Mn, if O is less than 15%, the manufacturing cost will increase, and the hardness of the steel plate will not be obtained.
．． If it exceeds 50%, it is not preferable in terms of manufacturing cost, iron loss, etc.

Within such a Mn range, hardness etc. can be maintained by reducing the amount of Mn and adding P, and the addition range is 0.01-0. ．． 080% is appropriate.

Next, 5OIA1. If the amount is less than 0.002%, there will be no problem in terms of magnetic properties, but it will cause problems in terms of material quality because, for example, deoxidization will be insufficient in terms of steel manufacturing. 0 again
．． If it exceeds 0.080%, the magnetic flux density may decrease and the characteristics as an electrical steel sheet may be lost, which is not preferable.

Next, regarding nitrogen in steel, it is preferably about 80 ppm or less. That is, as shown in FIG. 1, if it exceeds about 80 ppm, the iron loss may exceed 18, which is not preferable.

The remainder is impurities and iron, but as for Si.

There is no particular need to add it as an impurity in an unavoidable amount in steel manufacturing.

The test material in Figure 1 is aluminum killed steel with a plate thickness of 0.5'm.

Its chemical composition is clo, 04%, Si/≦0.03
%.

Al10.035%N/33ppm~0.0
5o, ~86. Such steel is made into steel billets by normal ingot making or continuous casting, and then processed by continuous hot rolling at a finishing temperature of 640 to 860°C and a winding temperature of 600 to 760°C. But 86
When the temperature rises above 0°C, it is above the transformation point, and the steel plate (111
) Since the strength increases, the magnetic flux density decreases, which is undesirable. Furthermore, if the temperature is lower than 640°C, the steel plate may become defective in shape, which is difficult to manufacture. That is, as shown in FIG. 2, it is clear that the magnetic flux density is improved in the finishing temperature range of 640 to 860'C. The sample material in Figure 2 has a plate thickness of 0.5111
+, chemical composition is Olo, 04%* Mn10.24%
, 5ojAE10.05% remaining Fe and impurities.

In the cold rolling process, the hot-rolled steel plate is subjected to the usual pickling-cold-rolling-annealing process, and temper rolling is used to straighten the shape of the steel plate.

There is a repeller treatment, but in temper rolling, the reduction rate is 0.
．． It is preferably less than 4%. In other words.

If the steel plate is subjected to strong rolling with a rolling reduction ratio of 0.4% or more, a large amount of distortion will occur in the steel plate, which may impair iron loss. The leveler treatment may be equivalent to the treatment of ordinary cold-rolled steel sheets.

The winding temperature of hot rolling is less than 600°C.

The shape of the steel sheet may be defective, and at a winding temperature of 760° C. or higher, a large amount of scale will form on the surface of the steel sheet, which is not preferable.

As described above, in the present invention, an excellent low-grade electrical steel sheet can be obtained by specifying the finishing temperature without changing the steel composition or adding alloys, etc., and is industrially inexpensive. Furthermore, an excellent electrical steel sheet can be obtained that can be fully used in general-purpose motors and the like.

Next, Examples of the method of the present invention are listed in Table 1 along with comparative examples. The component steels shown in Table 1 were melted in an oxygen top blowing furnace and manufactured through the steps of continuous casting, continuous hot rolling, pickling, cold rolling, annealing, and shape correction. (The components are residual impurities and iron.) Thus, according to the present invention, an excellent electrical steel sheet was obtained.

[Brief explanation of drawings]

Figure 1 is an explanatory chart showing the relationship between the amount of N in steel and iron loss. FIG. 2 is an explanatory chart showing the relationship between finishing temperature and magnetic flux density. 1st area 30 # , j; 0 6θ 7θ θθ
9θ /θθ Nitrogen (ppm) Dream 2 times Yu 4 extension A -1 degree (0C)

Claims (1)

[Claims] l C: 0.005 to 0.08%, Mn: 0.
15~0.50%, 5olAl: 0.002~
0.080%. Steel consisting of residual impurities and iron is processed in continuous hot rolling at a finishing temperature of 640 to 860°C and a winding temperature of 600 to 760°C, and then subjected to a normal cold rolling process to form a steel plate. Manufacturing method for low-grade electrical steel sheets. 2. O: 0.005-0.08%, Mn: 0.15
~0.50%, 5oJAA: 0.002~0.0
80%. N: 80 ppm or less, steel consisting of residual impurities and iron is continuously hot rolled at a finishing temperature of 640 to 860°C,
1. A method for producing a low-grade electrical steel sheet, which is characterized in that it is processed at a rolling temperature of 600 to 760° C. and then subjected to a normal cold rolling process to form a steel sheet.