JPH0419295B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a non-oriented electrical steel sheet with low iron loss and excellent magnetic flux density. (Prior technology) Non-oriented electrical steel sheets are widely used in motors and small and medium-sized transformers, etc., but in recent years, due to the strong demand for energy-saving electrical equipment, high efficiency has been developed for relatively inexpensive small and medium-sized electrical equipment. Demand for electrical steel sheets with low iron loss while maintaining high magnetic flux density is increasing in order to achieve this goal. In order to meet such demands, various steel companies are making earnest efforts to develop them, and the present inventors have previously discovered that the iron loss is W _15/505 / ₅₀ , as disclosed in Japanese Patent Application Laid-Open No. 151453/1983. We are developing and proposing a product with a magnetic flux density of B ₅₀ and 1.71T or more at 4.5w/Kg or less. FIG. 1 shows the relationship between iron loss value and magnetic flux density in a conventional component system. In other words, non-oriented electrical steel sheet is Si
There is a wide variety of grades, from high grade S9 with about 3% to S60 which contains almost no Si, and the higher the Si content, the lower the iron loss value. However, as the Si content increases, the magnetic flux density decreases. The curves 1 to 1' in FIG. 1 show the product characteristic range of the conventional product, and the broken line 2 is a straight line connecting the limit values of S09 to S23 in JIS standard C-2550. The range of dashed line 3 in Figure 1 is JP-A-Sho.
Although it is in the range of W _15/50 4.5w/Kg or less and B ₅₀ 1.71T or more as proposed in Publication No. 58-151453, special components such as Sn are added. (Problems to be Solved by the Invention) Conventional non-oriented electrical steel sheets either sacrifice magnetic flux density in order to obtain low iron loss values, or require expensive special components to obtain excellent magnetic properties. However, an object of the present invention is to provide a non-oriented electrical steel sheet that can obtain low iron loss and high magnetic flux density without adding components such as Sn. (Means for solving the problems) The present invention will be specifically explained below. The present invention develops [100] and [110] textures that are desirable for magnetic properties and controls [111] textures that are undesirable for magnetic properties by adding Cu to a component system with increased Mn content. The present invention aims to provide an electrical steel sheet with low magnetic flux density and low iron loss, and the present invention is particularly characterized by the fact that it has been found that the texture control effect of Cu is remarkable. The reasons for limiting the steel components of the present invention will be explained. Steel component [C] is a harmful component that worsens iron loss.
In order to inhibit crystal grain growth, the content should be 0.010% or less (all components are by weight). As is well known, Si is a component that has the effect of lowering the iron loss value, and if it is contained at 0.3% or more, the iron loss will improve, but on the other hand, as its content increases, the magnetic flux density will decrease as mentioned above, so it should be kept at 1.5% or less. . Al is an effective alloy as a deoxidizing agent, but when used for purposes other than deoxidizing, use 0.1% or more to increase specific resistance and lower iron loss. If it is less than 0.1%, magnetism deteriorates due to the formation of AlN, and if it exceeds 0.3%, the magnetic flux density decreases like Si. When Al is used only for the purpose of deoxidizing, it should be 0.1% or less, but since such an amount of Al causes AlN formation, which is harmful to magnetism, it is necessary to add B to generate BN and suppress the formation of AlN. For this purpose, a B/N ratio in the range of 0.5 to 1.5 is most effective and has been regulated. That is, B is added depending on the amount of N. Furthermore, if the amount of B increases too much, there is a risk of cracking of the steel billet, so it should be kept at 0.005% or less. As mentioned above, Mn is effective in controlling texture and improves magnetic properties, but if it is less than 0.7%, the effect is small, and if it is higher than 1.5%,
The transformation temperature decreases, making it difficult to perform stable grain growth annealing in the annealing process after hot-rolled sheets. Cu is an important component in the present invention, 0.1~1.0%
It exhibits a remarkable effect on improving magnetic properties within the range of . Like Mn, Cu is effective in controlling texture, but if it is less than 0.1%, the effect is small, and if it is more than 1.0%, it becomes brittle, causing problems in workability, processability, etc. Components other than those mentioned above are iron and unavoidable impurities. Next, the effect of adding Cu, which is a feature of the present invention, will be explained based on FIGS. 2 and 3. The above figures show the improvement in magnetism due to the addition of Cu to the low-Si materials in Table 1, and A in Figure 2 shows a slab of steel with the same composition, which is held at a temperature of 800℃ for 40 minutes after hot rolling. After self-annealing the hot-rolled sheet and then cold-rolling it to a thickness of 0.50mm,
This shows the magnetism of a so-called full process material, which is a product that has been subjected to continuous finish annealing at a temperature of 900°C for 40 seconds. B in the same figure shows the magnetism of a product (so-called semi-processed material) made by applying a similar self-annealed material to a thickness of 0.50 mm in one cold rolling process and then annealing it at a temperature of 750℃ for 2 hours. This is what is displayed. In addition, C in Fig. 3 is a hot-rolled self-annealed material similar to that in Fig. 2, which is cold-rolled, intermediate annealed, and then subjected to a 4% skin pass. This relates to a semi-processed material that has been annealed, and D in the figure relates to a semi-processed material that has been subjected to 10% skin pass rolling (other treatments are the same as C in FIG. 3). Even though the manufacturing process is different in this way, the iron loss value (W _15/50 ) decreases with the addition of Cu, and shows a particularly rapid decrease after 0.1%. However, there is almost no change in magnetic flux density (B ₅₀ ), and all of them show good values of 1.71 T or more.

[Table] From the above, it is recognized that magnetic properties are improved by adding 0.1% or more of Cu, but from the viewpoint of workability, processability, etc., 1.0% or less is an appropriate range. (Function) Next, the manufacturing conditions of the present invention will be explained. After hot-rolling the slab with the above-mentioned components by conventional means, it is rolled up at a temperature of 700°C or higher for 10 minutes or more.
Self-annealed for 40 minutes or after hot rolling
The hot rolled sheet is annealed at a temperature of 750°C or higher and lower than the α-γ transformation temperature. The material is then cold-rolled at a normal rolling reduction rate to achieve a product thickness, and is used in so-called full-process materials, which are subjected to continuous annealing for grain growth below the transformation temperature. Furthermore, semi-processed materials, including those subjected to skin pass rolling, etc., which are subsequently subjected to customer annealing, can also be used as described above, and good magnetic properties can be added to them. (Example) (1) A slab with the composition shown in Table 1 added with 0.5% Cu was hot-rolled, self-annealed at a temperature of 830°C for 40 minutes, and then cold-rolled at a reduction rate of 78%.
A cold-rolled plate with a thickness of 0.50 mm was made, and was continuously annealed at 900℃ for 40 seconds, followed by customer annealing at 750℃ for 2 hours. Iron loss W _15/50 : 3.34w/Kg Magnetic flux density B ₅₀ : 1.76T
I got it. (2) The same hot-rolled steel plate as in Example (1) was prepared with an intermediate plate thickness of 0.52.
After cold rolling to mm and intermediate annealing at 775℃×60sec,
A product sheet of 0.50 mm was produced by skin pass rolling with a rolling reduction of 4%, and then annealed at 750°C for 2 hours to obtain the following magnetic properties. W _15/50 : 3.24w/Kg B ₅₀ : 1.75T (3) The same hot-rolled steel plate as in Example (1) with an intermediate thickness of 0.56mm.
After that, intermediate annealing was performed at 900°C for 40 seconds, followed by skin pass rolling with a rolling reduction of 10% to give a product thickness of 0.50 mm. Then 750℃×2
The magnetic properties after customer annealing for several hours were as follows. W _15/50 : 3.05w/Kg B ₅₀ : 1.72T (4) A steel slab with the composition shown in Table 2 was hot rolled, self-annealed at a temperature of 820℃ for 60 minutes,
After cold-rolling with a reduction rate of 81% to form a cold-rolled sheet with a thickness of 0.50 mm and continuous annealing at 850°C for 60 seconds,
Customer annealing was performed at 750°C for 2 hours to reduce iron loss.
W _15/50 : 3.30w/Kg, magnetic flux density B ₅₀ : 1.78T were obtained. (5) The same self-annealed hot rolled steel sheet as in Example (4) was cold rolled to an intermediate thickness of 0.56 mm, then intermediate annealed at 850°C for 60 seconds, and then skin pass rolled at a rolling reduction of 10%. was applied to produce a product plate with a thickness of 0.50mm. Thereafter, the magnetic properties after customer annealing at 750°C for 2 hours were as follows. W _15/50 : 2.98W/Kg B ₅₀ : 1.74T

[Table] The magnetic properties of each of the above examples are plotted in the range shown by 4 in FIG. That is, Examples 1, 2, 3, 4, 5
are A ₁ , A ₂ , A ₃ , A ₄ , and A ₅ , respectively. The iron loss of the material of the present invention is lower than that of Examples B ₁ , B ₂ , and B ₃ (all semi-processed materials with a plate thickness of 0.50 mm) described in the known example (Japanese Patent Application Laid-Open No. 151453/1983) in this figure. Moreover, the magnetic flux density is found to be over 1.71T at _B50 . (Effects of the Invention) According to the present invention, electrical steel sheets with low core loss and high magnetic flux density can be obtained using composition steel without Sn addition, and can fully meet the strong demand for inexpensive and high-efficiency electrical steel sheets. The effect is very large.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the magnetic properties of the steel of the present invention and conventional steel, and FIGS. 2 and 3 are diagrams showing the relationship between the amount of Cu and the magnetic properties of the steel of the present invention.

Claims (1)

[Claims] 1. By weight, C: 0.010% or less, Si: 0.3 to 1.5%,
Mn: 0.7~1.5%, Cu: 0.1~1.0%, acid soluble Al:
A non-oriented electrical steel sheet with low iron loss and excellent magnetic flux density, characterized by containing 0.1 to 0.3% and the remainder consisting of Fe and unavoidable impurities. 2 By weight, C: 0.010% or less, Si: 0.3-1.5%,
Mn: 0.7~1.5%, Cu: 0.1~1.0%, acid soluble Al:
Contains 0.1% or less and B: 0.005% or less, and has a B/N of 0.5 to 1.5, with the remainder consisting of Fe and unavoidable impurities, and has low iron loss.
A non-oriented electrical steel sheet with excellent magnetic flux density.