JPH03229820A - Production of nonoriented silicon steel sheet - Google Patents

Abstract

PURPOSE:To improve the magnetic properties, such as iron loss, of a blanked, sheared, and stress-relief-annealed stock by subjecting an Al-containing steel in which P content is properly regulated to hot rolling under specific temp. Conditions, applying pickling and cold rolling to the resulting rolled plate, and then subjecting the resulting rolled sheet to annealing. CONSTITUTION:A steel having a composition consisting of, by weight, <=0.0050% C, 0.06-1.0% Si, 0.5 1.5% Mn, 0.01-0.06% P, <0.010% S, 0.1-0.5% Al, <=0.0050% N, and the balance Fe with inevitable impurities is cast. The resulting cast slab is hot-rolled under the conditions of <=1170 deg.C heating temp., Ar3 transformation point or below of finishing temp., and 600-720 deg.C coiling temp. After pickling and cold rolling, the resulting sheet is annealed at 625-800 deg.C. This steel sheet is subjected, if necessary, to the application of an insulating film, etc., and to baking, by which a semiprocessed steel sheet is formed. This steel sheet is blanked and sheared and is then subjected to stress relief annealing so that heating rate HR( deg.C/min) at 350-700 deg.C satisfies HR>=60[P]+1.4, where P means P content in the steel sheet. By this method, a nonoriented silicon steel sheet excellent in magnetic properties can be produced.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a method for producing semi-processed non-oriented electrical steel sheets, which is premised on being subjected to stress relief annealing after punching and shearing at the customer's end; The present invention relates to a method for manufacturing non-oriented electrical steel sheets including punching/shearing and strain relief annealing processes.

[Conventional technology]

In recent years, due to social demands for energy conservation, there have been demands for improving the efficiency of small motors used in refrigerators, air conditioners, etc., downsizing fluorescent lamp ballasts, and preventing temperature rises. There is also a strong need for high magnetic flux density and low core loss for grain-oriented electrical steel sheets.

Against this background, in recent years there has been an increase in demand for so-called low-grade non-oriented electrical steel sheets with 2.0% SiS, which have relatively high iron loss but are low cost and have high magnetic flux density, and demands for lower iron loss. It is increasing. A semi-processed material that embodies the low core loss of such a low-grade non-oriented electrical steel sheet is a steel sheet that is punched and sheared at the customer's end and then subjected to stress relief annealing. This semi-processed material has the following (1):
It is broadly classified into (2).

(1) After primary cold pressing and annealing, the product is subjected to pressure adjustment of about 1 to 10% as secondary cold pressing, and then punched and sheared by the customer, followed by strain relief annealing. Semi-processed material by double cold pressing. This steel sheet coarsens the crystal grains during strain relief annealing through whole-grain growth due to controlled strain, and is intended to reduce core loss, but it also has the drawback of decreasing magnetic flux density.

(2) Semi-processed material (in terms of process), which is cold-rolled and annealed once in the same way as full-processed material, then punched and sheared at the customer's end, and then annealed to remove strain. Since the full process material is annealed again by the consumer, it will be referred to as ``full process annealed material'' for convenience hereafter). Although this steel plate has a smaller iron loss reduction formula than that obtained by double cold pressing, it has the advantage that the magnetic flux density does not decrease much.

Of these, demand has recently increased rapidly for (2) full-process annealed materials, which are advantageous in terms of magnetic flux density, in addition to conventional (1) semi-processed materials from the viewpoint of downsizing and increasing efficiency of equipment. . In the case of such a full process annealed material, the challenge is to improve the iron loss, which is inferior to the semi-processed material by two cold pressures (1), without deteriorating the magnetic flux density.

Conventionally, the following techniques have been disclosed for improving iron loss or magnetic flux density of full process annealed materials.

First, there are the following technologies that take manufacturing processes into consideration.

(a) JP-A-57-35628: Technology for short-time annealing of hot-rolled sheets (b) JP-A-58-136718: Substitution of short-time annealing of hot-rolled sheets by self-annealing using ultra-high temperature coiling Technology (c) JP-A No. 61-15920: A hot-rolled sheet finish-rolled above the Ar3 transformation point is water-cooled to refine the structure, and then annealed at a low temperature of about 1 recovery annealing after cold rolling. There are also techniques for keeping the structure fine and thereby improving grain growth during strain relief annealing, as well as techniques that take component conditions into consideration. That is, these are techniques for increasing the grain size after strain relief annealing and reducing iron loss by improving grain growth during strain relief annealing in consideration of the components.

(i) Regarding prevention of precipitation of fine AIN that deteriorates grain growth (d) Japanese Patent Publication No. 59-20731; Adding B to Al≦0.1% steel and fixing N as BN that has less negative effect on grain growth (e) Japanese Patent Publication No. 62-49321: Same as above (f) Japanese Patent Publication No. 62-21849: Same as above (g) Japanese Patent Publication No. 58-55210: Al≦0.001%, making it virtually AIN-free Technology (lid) Regarding prevention of precipitation of fine MnS that deteriorates grain growth (h) Ultra-low S reduction technology (i) JP-A-63-103023: Adding Ca to S in Al≦0.002% steel [Problem to be solved by the invention] As described above, various techniques have been proposed for improving the properties of full process annealed materials, but all of these techniques are as follows: It has the following problems.

First, among the manufacturing processes taken into consideration, (a) is the increase in cost due to the addition of hot-rolled sheet annealing, and (b) is the increase in scale due to ultra-high temperature coiling and the resulting decrease in pickling properties.
Alternatively, significant deterioration of surface properties due to grain boundary oxidation becomes a problem. In addition, in (C), in addition to poor shape of the hot-rolled sheet due to water cooling, significant hardening caused by low-temperature annealing causes problems during punching and shearing. As described above, there are still many problems to be solved by modifying the manufacturing process, and it is far from completely satisfactory.

In addition, considering the components, all of (d) to (i) are A1≦0.1% (from the examples etc., it is substantially Al
≦0.02%), and AI≧0.
No useful technology has been found for improving the properties of steel containing 1%. Of course, A1≧0.1%
In steel, AIN precipitates relatively coarsely, so AIN
Although it is not necessary to consider AI, it is an element that should be actively used in manufacturing full process annealed materials with low core loss, as it greatly increases the specific resistance.In this sense, AI≧0.1% It is desirable to improve the properties of steel.

In view of these circumstances, the present invention aims to improve the properties of full process annealed materials containing 0.1% or more of AI and punched/sheared knee strain relief annealed materials made from the full process annealed materials, especially reducing iron loss. Its purpose is to improve.

[Means to solve the problem]

As a result of extensive research into improving the properties of full-process annealed materials with A1≧0.1%, the present inventors found that, in addition to controlling the precipitation of AIN and MnS, the amount of P was optimized and heating during strain relief annealing was conducted. The present invention was completed based on the new discovery that optimizing the speed is important.

That is, the configuration of the present invention is as follows.

(1) 1% by weight in the manufacturing method of semi-processed non-oriented electrical steel sheet, which is subjected to strain relief annealing after punching and shearing.
So, C≦0.0050%, 0.06%≦Si≦1.0%
, 0.5%≦Mn≦1.5%, 0.01%≦P≦0.0
6%, S<0.010%, 0.1%≦Al≦0.5%,
Steel consisting of N≦0.0050%, balance Fe and unavoidable impurities was heated at a heating temperature of 1170°C or less and a finishing temperature of Ar3.
Below the transformation point, hot-rolled at a coiling temperature of 600°C or higher and 720°C or lower, then pickled and cold rolled, then annealed at a temperature of 625°C or higher and 800°C or lower to form an insulating film, etc. as necessary. A method for producing a non-oriented electrical steel sheet, characterized by applying coating and baking.

(2) In weight%, C≦0.0050%, 0.06%≦S
i≦1゜0%, 0.5%≦Mn≦1.5%, 0.01%
≦P≦0.06%, S(0,010%, 0.1%≦AI
≦0.5%, N≦0.0050%.

After hot rolling the steel consisting of the remainder Fe and unavoidable impurities at a heating temperature of 1170° C. or lower, a finishing temperature of Ar, and a coiling temperature of 600° C. or higher and 720° C. or lower below the transformation point, then pickling and cold rolling, Annealed at a temperature of 625°C or more and 800°C or less, coated with an insulating film or baked as necessary to make a semi-processed steel plate, and after punching and shearing the steel plate, The strain relief annealing is performed such that the heating rate HR ('C/5in) satisfies the following: HR≧60[P] + 1.4, where P: P content of the steel sheet (st%) A method for manufacturing non-oriented electrical steel sheets.

[For production]

The details of the present invention will be explained below along with the reasons for its limitations.

First, the reason for limiting the component composition in the present invention is as follows.

(1) P amount P is usually widely added to fully processed materials and semi-processed materials as an element that increases hardness and improves punchability without deteriorating magnetic properties. Therefore, even in the case of a full process annealed material, which is the object of the present invention, if it is necessary to increase hardness and improve punchability, a relatively large amount (0.1%
It is usually added before and after). In this way, conventional P
Regarding the merits and demerits of P, only its hardness increase and punchability improvement effects have been clarified, and it can be said that there are currently no other technologies that focus on the merits and demerits of P. However, the present inventors According to a detailed review of the merits and demerits of P in full process annealed materials.

Although P certainly increases hardness and improves punchability, there is an appropriate value for the amount of P when it comes to magnetic properties, especially iron loss, and only when P is controlled to this appropriate amount can iron loss be improved through an increase in specific resistance. If P is added in excess of this appropriate amount (conventionally, P is added within this range), it will inhibit grain growth during strain relief annealing, and on the contrary, it will cause the iron to deteriorate. It was found that this resulted in an increase in losses. Therefore, in the present invention, the above-mentioned appropriate range of P is a requirement.

Furthermore, as a result of further investigation, we found that the presence of an appropriate amount of P for iron loss is unique to fully process annealed materials, and that such an appropriate amount is required for fully process materials and semi-processed materials subjected to double cold pressing. The existence of was not recognized. In other words, as is well known, iron loss largely depends on the grain size, but in full-process materials, the structure is formed at relatively small grain sizes during cold pressing and annealing, so the driving force for grain growth is high. , and the annealing conditions (particularly the annealing temperature) have an overwhelming influence on the grain size, so it is thought that the influence of P does not become apparent. Also, in the case of semi-processed materials subjected to double cold pressing, the influence of P does not become apparent because the grain growth uses pressure regulating strain as its driving force. On the other hand, in the case of full process annealed materials, the grains are once grown to a certain grain size by cold pressure annealing, and then strain relief annealing is performed again by the customer to cause the grains to grow even coarser. In addition to the fact that the driving force for grain growth is only the energy difference between grain boundaries, the driving force itself is small, and it is thought that the influence of P on grain growth becomes obvious. The mechanism of the effect of P on grain growth is not necessarily clear, but
P is an element that tends to segregate at grain boundaries, and therefore 5ol
Grain boundary mobility (n
It is thought that the essence of this is to reduce the ability of the user.

Next, the merits and demerits of the above-mentioned P will be clarified based on test examples, and the limiting range and reason for the appropriate amount of P will be explained.

C: 0.0028%, Si: 0.31%, Mn
: 0.81%, S: 0.003%, Al: 0.1
3%, N: constant at 0.0019%, P amount 0.0
Steel with various changes from 02 to 0.088% (A group), and C: 0.0043%, Si: Q, 80%, An:
1.31%, s: o, ooa%, Al:
Using steel (Group B) with a constant P content of 0.38%, N: 0.0035%, and varying P content from 0.003 to 0.091%, the slab was heated to 1150°C and then finished at a finishing temperature of 82%.
Hot rolled under the conditions of 0℃ and coiling temperature of 670℃, and after pickling
．． Cold rolled to a finish thickness of 5 mm, annealed at 700°C, and then continued at 750°C x 2 hours, which is equivalent to strain relief annealing at the customer.
It was subjected to annealing at a heating rate of 7° C./win. Figure 1 shows the amount of P and iron loss (WIS/S) of the sample material obtained in this way.
. ) and magnetic flux density (BS.).

As is clear from the figure, in both groups A and B, the amount of P is only in the range of 0.01 to 0.06%, in group A it is around 4.4 W/kg, and in group B it is 3.0 W/kg. A good iron loss value of around 6 W/kg was obtained. On the other hand, when the P content is less than 0.01%, the formula for improving iron loss due to increased resistivity is small, and when the P content exceeds 0.06%, the formula for improving iron loss due to increased resistivity is Since the deterioration exceeds that, the iron loss is higher by 0.6 W/kg or more in both groups A and B than in the range of P: 0.01 to 0.06%.

In this way, there is an appropriate range for the amount of P, and this is 0.0 regardless of group A or group B, that is, regardless of the steel type.
Since it is 1 to 0.06%, in the present invention, the amount of P is 0.01%.
It was defined as ~0.06%. Also, B. Regarding P
When the amount is 0.06% or less, the decrease in B5o due to an increase in the amount of P is small, and when the amount of P is 0.01-0.06%, it is good. It can also be seen that it can be obtained.

(2) As mentioned above for other components, by optimizing the amount of P within the range of 0.01 to 0.06%, the iron loss of full process annealed materials containing 0.1% or more of Al can be significantly improved. be done. However, it goes without saying that optimizing only the amount of P does not mean that other components are allowed within any range, and that there are naturally appropriate amounts and ranges. The ranges of other components and the reasons for their limitations will be explained below.

C: If it exceeds 0.0050%, the magnetic properties will deteriorate and there will be problems with magnetic aging, so the upper limit is 0.0050%, which is an ultra-low carbon steel.

Sj: Has the effect of increasing specific resistance and reducing iron loss,
To fully obtain this effect, it is necessary to add 0.06% or more. On the other hand, when added in excess of 1.0%, the magnetic flux density decreases and
The upper limit is set at 1.0% because it also increases costs.

Mn=An element that can improve iron loss without significantly deteriorating magnetic flux density, but in order to fully exhibit this effect, it is necessary to add 0.5% or more. On the other hand, 1.5%
Even if Mn is added in an amount exceeding this amount, the above effect will be saturated and the cost will increase. For the above reasons, Mn is 0.5~
It shall be 1.5%.

S: If it is 0.010% or more, grain growth deteriorates and iron loss increases, so it needs to be less than 0.010%.

Al: Like Sj, it is an element that reduces iron loss and should be actively added, but if it is less than 0.1%, it forms fine AIN and impairs grain growth. In order to prevent this and obtain a good iron loss value, the lower limit is set to 0.1%.

However, if it is added in excess of 0.5%, the magnetic flux density will decrease,
Also, to avoid unnecessary cost increases, the upper limit is set at 0.5%.

N: If it exceeds 0.0050%, the magnetic properties will deteriorate, so the upper limit is set at 0.0050%.

Next, processing conditions will be explained.

Based on the above-mentioned components, the third requirement of the present invention is to specify the processing conditions as described below. Even if the ingredients are optimized, this will only have a noticeable effect under certain specific processing conditions, and if these conditions are exceeded, the effect of ingredient optimization will be greatly reduced. It is.

(1) Hot-rolling heating temperature If the hot-rolling heating temperature is unnecessarily high, AIN and MnS, which have once precipitated coarsely at the slab stage, will be re-dissolved and then finely re-precipitated, resulting in deterioration of grain growth.

In that case, regarding AIN, the steel of the present invention has an AI≧0.1
%, coarsening of AIN tends to occur during reprecipitation,
The upper limit of the heating temperature is thought to be relatively high, but Mn
Regarding S, such coarsening cannot be expected. Therefore, the upper limit of the heating temperature is determined mainly from the viewpoint of redissolution and reprecipitation of MnS. Under such consideration,
The present inventors conducted the following experiments and studies and determined the upper limit of the hot rolling heating temperature.

C: 0.0028%, Si: 0.31%, Mn:
0.81%, P: 0°057%, S: 0.003
%, Al: 0.13%, N: 0.0019% (both steel C1 components are within the scope of the present invention) and C
: 0.0043%, Si: 0.80%, Mn: 1
．． 31%.

P: 0.015%, S: 0.008%, Al
: 0.38%, N: 0.0035% (
After heating the slab to various temperatures, the finishing temperature was 820°C and the winding temperature was 7.
The product was hot rolled at 00℃, pickled and then cold rolled to a finish thickness of 0.5℃, annealed at 700℃, and then heated at 750''CX2hr (heating rate) equivalent to strain relief annealing at the customer. 7
℃/5in).

Figure 2 shows the iron loss (W,...
,,. ) are arranged by hot rolling heating temperature. From the same figure, it can be seen that steel C5 steel, that is, regardless of the steel type, the heating temperature is 1170°C or less, and steel C is W. / 5. <
4.5W/kg, W for steel.

7sI, it can be seen that a good iron loss value of around 3.6 W/kg can be obtained. On the other hand, if the heating temperature exceeds 1170°C, grain growth deterioration mainly due to remelting and fine reprecipitation of MnS will cause rusted C1 steel whose composition is within the range of the present invention to exceed 1170°C. WIS/S compared to the case of heating. is higher than 0.5 W/kg.

Regarding the magnetic flux density (B, .), in the above study range, it is around 1°75 T for steel C and 1.72 T for steel.
It was almost constant between before and after, and the influence of hot rolling heating temperature was small.

Based on the above results, the present invention specifies the heating temperature in hot rolling to be 1170° C. or lower.

(2) Hot rolling finishing temperature Ar: If hot rolling is finished at a temperature above the transformation point, the magnetic properties, particularly the magnetic flux density, will be significantly reduced, so the finishing temperature is set below the Arc transformation point.

(3) Hot rolling coiling temperature Using steel C and steel used in Figure 2, the slab was
After being heated to 140°C, the finishing temperature was kept constant at 830°C and the winding temperature was varied and hot rolled.
(2) It was cold rolled to a thick thickness, then annealed at 700°C, and then annealed at 750°C for 2 hours (heating rate 7°C/win), which is equivalent to strain relief annealing at the customer. Figure 3 shows the iron loss (W process, 7..) and magnetic flux density (
B. ) and surface roughness Ra are arranged according to the hot rolling coiling temperature.

From the same figure, it can be seen that steel C1 has good magnetic properties (Steel C: Wx-y-o" 4-5W/kg, Bs.

! 1.75 T, Steel D: Wlsy,. z3.
6W/kg, B-8! 1.72 T”) and surface texture (Ra<0.4μm).On the other hand, even with steel C1 that satisfies the compositional conditions of the present invention, the coiling temperature is less than 600℃. In the case of , the progress of recrystallization of the hot-rolled sheet, the coarsening of grains, and the coarsening of AIN and MnS are insufficient, and both iron loss and magnetic flux density are significantly deteriorated.

On the other hand, if the winding temperature exceeds 720°C, although there is no problem with magnetic properties, an internal oxidation layer that is difficult to pickle will develop during winding, and grain boundary oxidation will be significant, and this will occur during pickling. Grain boundary invasion occurs, and this causes frequent microcracks during cold pressing, resulting in significant deterioration of the surface quality to Ra) 0.7 μm.

From the above results, in the present invention, the coiling temperature in hot rolling is defined as 600°C or more and 720°C or less.

(4) Pickling and cold rolling There is no need to specify anything in particular, and they can be carried out by conventional methods.

(5) Annealing temperature after cold pressing When this annealing temperature exceeds 800°C, the grain size becomes coarse.
(111) grains, which are unfavorable in terms of magnetic properties, develop and the magnetic flux density decreases. The upper limit is set at 800° C. since the softening is also significant, and due to the curling of the coil, defective products are likely to be produced during punching or when stacking and caulking the punched products. on the other hand.

The iron loss after strain relief annealing at the customer's end hardly depends on the main annealing temperature after cold pressing, so from this point of view there is no lower limit to the annealing temperature, but if low temperature annealing below 625°C is performed, Hardening significantly leads to deterioration of punching properties. That is,
Since extremely hard materials are punched, the die is subject to severe wear and tear, and the increase in burr height during continuous punching is accelerated. Therefore, the lower limit of the annealing temperature needs to be 625°C.

(6) Annealing conditions after punching and shearing After the above-mentioned annealing, the steel plate is coated with an insulating film and baked as necessary to become a final product as a full process annealed material, and then punched and sheared. Then, strain relief annealing is performed.

This punching/shearing process and stress relief annealing are normally performed at the customer.

For full-process annealed materials manufactured under the conditions described above, the heating rate during strain relief annealing is important in order to obtain the desired magnetic properties, and the manufacturing method of the steel sheet, including strain relief annealing, is important. Considering this, it is necessary to specify the heating rate during strain relief annealing.

This is because, as mentioned above, during strain relief annealing, grain boundary mobility decreases due to 5olute-drag caused by grain boundary segregation of P, and grain growth deteriorates. However, even if the amount of P is reduced in this way, if the heating rate during strain relief annealing is inappropriately slow, grain boundary movement and grain boundary segregation of P may compete, or the latter may Advantage 1: Grain boundaries cause P segregation, and then the grain boundaries have no choice but to move the segregated P as a solute-drag, resulting in a decrease in grain boundary mobility, that is, a deterioration in grain growth. It is. Therefore, regarding the heating rate during strain relief annealing, there is a lower limit value depending on the ease of segregation, that is, the amount of P. Moreover, since the problem here is grain boundary segregation of P, the lower limit of the heating rate should be considered in the range of 350 to 700° C. where grain boundary segregation is active.

Hereinafter, the lower limit of this heating rate and the reason for the limitation will be explained based on test examples.

Using the aforementioned steel groups A and B, the slab was heated to 1130°C.
After being heated to , hot rolled at a finishing temperature of 840°C and a coiling temperature of 700°C, pickled and cold rolled to a finishing thickness of 0.5 mm, then annealed at 700°C and subsequently sold to customers. Annealing at 750°C for 2 hours, which is equivalent to strain relief annealing at
The heating rate at ~700°C was varied. Fourth
The figure shows the iron loss (W□515) of the sample material obtained in this way.
0) as P amount and heating rate HR at 350 to 700°C (
℃/m1n). From the same figure, 0.
In the steel of the present invention satisfying 01≦P≦0.06%, A
In both groups and B, regardless of the steel type, the lower limit of the heating rate HR is HR = 60 [P] + 1.4, which is a function of the amount of P, and when the heating rate is higher than this, in group A, W Engineering, 7. . <4.6 W/kg, W in group B
It can be seen that a good iron loss value can be obtained, with an iron loss value of <3.7 W/kg. On the other hand, even if 0.01≦P≦0
．． Even if the steel satisfies the present invention composition condition of 0.6%, if the heating rate falls below the lower limit specified by the above formula, the grain growth during strain relief annealing will deteriorate due to grain boundary segregation of P. ,A
The iron loss in both group and B group increases by 0.3 W/kg or more.

It can also be confirmed that in steels with P<0.01% or P)0.06%, which is outside the range of the present invention, good iron loss cannot be obtained at any heating rate. Note that the influence of the heating rate on the magnetic flux density (B, .) was small.

From the above results, in the present invention, the heating rate HR during strain relief annealing is
('C/m1n) is defined as HR≧60 [P amount + 1.4. On the other hand, there is no need to specify the upper limit from the viewpoint of magnetic properties, but if the heating rate is increased unnecessarily, the temperature distribution becomes non-uniform and the steel sheet is thereby deformed.

Therefore, the upper limit of the heating rate needs to be determined for each customer by taking into account the specifications of the strain relief annealing furnace, the amount of annealing, etc.

Regarding strain relief annealing temperature and time, grain boundary segregation of P can be avoided by optimizing the heating rate as described above, so there is no need for special consideration, and the temperature and time are 720 to 800 as usual.
℃ for about 1 to 2 hours.

〔Example〕

A slab having the steel composition shown in Table 1 was hot rolled under the hot rolling conditions shown in Tables 2-a to 2-c, and after pickling, the finished thickness was 0.
After cold rolling to No. 5, it was annealed for 3 min at the annealing temperature shown in the same table.

Regarding the annealed plate thus obtained, each vertex is 0.
1 with a 38 rectangular punching die (SKS3), a clearance of 7%, a speed of 200 spm, and the use of punching oil.
A continuous punching test was conducted for 50,000 times, and the burr height after 150,000 punches was measured. In addition, after subjecting the above annealed plate to annealing at 750°C for 2 hours, which is equivalent to strain relief annealing at the customer,
The magnetic properties were evaluated using the Epstein test based on the JIS method. The results of these measurements are also shown in Tables 2-a to 2-c.

Of these examples, Table 2-a shows the effects of component conditions, Table 2-b shows the effects of hot rolling-annealing conditions, and Table 2-c shows the effects of heating during strain relief annealing. The influence of speed was investigated.

As is clear from Tables 2-a to 2-c, the products produced by the method of the present invention have good magnetic properties (iron loss: W, 7.0 and magnetic flux density: B5°) and punchability (burr height). Sa≦25μ
m) has been obtained. On the other hand, the comparative method (one in which either the components or manufacturing conditions are outside the scope of the present invention) is inferior in core loss, magnetic flux density, or punching property (iron loss: W process, 7. is 0.5W/k compared to the method of the present invention.
g or higher, and the magnetic flux density 2B5o is 0.g higher than that of the method of the present invention.
02 T or more low). In addition, among the comparative methods, the annealing temperature is lower than the lower limit of the conditions of the present invention, although the magnetic properties are good, the burr height in the punching test is 50 μm or more, and the punching performance is deteriorated. I know that there is.

〔Effect of the invention〕

According to the present invention described above, a full process annealing material of a non-oriented electrical steel sheet that easily has excellent magnetic properties and punchability without causing a cost increase due to the addition of special alloying elements or addition of processes, and A punched, sheared, strain-relieving annealed material can be manufactured using this material.

[Brief explanation of drawings]

FIG. 1 is a graph showing the influence of the amount of P on iron loss and magnetic flux density and its appropriate range. FIG. 2 is a graph showing the influence of hot rolling heating temperature on iron loss and its appropriate range. Figure 3 shows iron loss. It is a graph showing the influence of hot rolling winding temperature on magnetic flux density and surface roughness and its appropriate range. FIG. 4 is a graph showing the influence of the heating rate and the amount of P during strain relief annealing on iron loss and its appropriate range. 0.02 0.04 0.06 0.08 0.10 P amount (Wtolo> Bamboo Aj ? Figure 000 1100 1200 1300 Melting heating temperature l
11 (0C) Diagram Temperature of hot rolling (0C)

Claims (2)

[Claims] (1) In a method for manufacturing semi-processed non-oriented electrical steel sheets in which strain relief annealing is performed after punching and shearing, weight%
So, C≦0.0050%, 0.06%≦Si≦1.0%
, 0.5%≦Mn≦1.5%, 0.01%≦P≦0.0
6%, S<0.010%, 0.1%≦Al≦0.5%,
Steel consisting of N≦0.0050%, balance Fe and unavoidable impurities is heated at a heating temperature of 1170°C or less and a finishing temperature Ar_
3 transformation point or lower, hot rolling at a coiling temperature of 600°C or higher and 720°C or lower, then pickling and cold rolling, then 625°C
A method for producing a non-oriented electrical steel sheet, which comprises annealing at a temperature of 800° C. or lower, and applying and baking an insulating film or the like as necessary. (2) In weight%, C≦0.0050%, 0.06%≦S
i≦1.0%, 0.5%≦Mn≦1.5%, 0.01%
≦P≦0.06%, S<0.010%, 0.1%≦Al
Steel consisting of ≦0.5%, N≦0.0050%, balance Fe and unavoidable impurities is heated at a heating temperature of 1170°C or lower, a finishing temperature of Ar_3 or lower than the transformation point, and a coiling temperature of 600°C or higher72
After hot rolling at 0°C or lower, then pickling and cold rolling, annealing at a temperature of 625°C or higher and 800°C or lower, and applying and baking an insulating film as necessary to produce a semi-processed steel sheet. None, after punching and shearing the steel plate, 350
Heating rate HR in the temperature range of ~700°C (°C/min
), HR≧60[P]+1.4, where P: P content (wt%) of the steel sheet.