Title of invention: Method for manufacturing non-directional electromagnetic steel plate
Technical field
[0001]
The present invention relates to a method for manufacturing a non-directional electromagnetic steel plate.
This application claims priority based on Japanese Patent Application No. 2019-206630 filed in Japan on November 15, 2019, and Japanese Patent Application No. 2019-206812 filed in Japan on November 15, 2019. , The contents are used here.
Background technology
[0002]
The non-directional electromagnetic steel plate is used, for example, for the iron core of a motor. The non-directional electromagnetic steel plate has excellent magnetic properties in the average in all directions parallel to the plate surface (hereinafter, may be referred to as "overall circumference average in the plate surface (omnidirectional average)"). For example, it is required to have low iron loss and high magnetic flux density.
[0003]
Although various techniques have been proposed so far, it is difficult to obtain sufficient magnetic characteristics in the all-around average in the plate surface. For example, even if sufficient magnetic characteristics can be obtained in a specific direction within the plate surface, sufficient magnetic characteristics may not be obtained in other directions.
Prior art literature
Patent documents
[0004]
Patent Document 1: Japanese Patent No. 4029430
Patent Document 2: Japanese Patent No. 6319465
Outline of the invention
Problems to be solved by the invention
[0005]
In view of the above-mentioned problems, it is an object of the present invention to provide a method for manufacturing a non-directional electromagnetic steel plate capable of obtaining excellent magnetic characteristics with an all-around average (omnidirectional average) in a plate surface.
[0006]
Further, the non-directional electromagnetic steel plate is preferably a material that is easy to process when processing the iron core of the motor in order to reduce the production cost. Therefore, an object of the present invention is preferably to provide a non-directional electromagnetic steel plate which can obtain excellent magnetic properties with an all-around average (omnidirectional average) and has excellent workability.
Means to solve the problem
[0007]
The present inventors have made diligent studies to solve the above problems. As a result, the present inventors presuppose the chemical composition of the α-γ transformation system in the production of the non-directional electromagnetic steel plate capable of obtaining excellent magnetic properties on the whole circumference average in the plate surface. Overhang recrystallization by refining the crystal structure by transformation from austenite to ferrite during hot rolling, performing the first cold rolling at the desired cumulative reduction rate, and performing intermediate quenching under the desired conditions ( By generating bulging), it is easy to develop {100} crystal grains that are normally difficult to develop, second cold rolling (skin pass rolling) under desired conditions, and finish annealing or strain removal annealing. It was found that it is important for the {100} crystal grains to erode the {111} crystal grains.
[0008]
The gist of the present invention made based on the above findings is as follows.
(1) The method for manufacturing a non-directional electromagnetic steel plate according to one aspect of the present invention is based on mass%.
C: 0.0100% or less,
Si: 1.50-4.00%,
Sol. Al: 0.0001 to 1.000%,
S: 0.0100% or less,
N: 0.0100% or less,
Mn, Ni, Co, Pt, Pb, Cu and Au: 2.50 to 5.00% in total,
Sn: 0.000 to 0.400%,
Sb: 0.000 to 0.400%,
P: 0.000 to 0.400%, and
Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: Containing 0.0000 to 0.0100% in total,
By mass%, Mn content is [Mn], Ni content is [Ni], Co content is [Co], Pt content is [Pt], Pb content is [Pb], and Cu content is [Cu]. ], Au content is [Au], Si content is [Si], sol. Al content is [sol. When expressed as [Al], the following equation (1) is satisfied.
A process of hot-rolling a steel material having a chemical composition in which the balance is composed of Fe and impurities and winding it in a temperature range of more than 250 ° C and 550 ° C or less to obtain a hot-rolled steel plate.
The process of performing the first cold rolling on the hot rolled steel plate and
The process of performing intermediate annealing after the first cold rolling and
The process of performing the second cold rolling after the intermediate quenching and
It has a step of performing one or both of finish annealing and strain removal annealing after the second cold rolling.
Perform the final pass of finish rolling during hot rolling in a temperature range above Ar1 temperature,
In the finish annealing, hold for 2 hours or less in a temperature range below Ac1 temperature.
In the strain removing and annealing, the temperature is maintained at 600 ° C. or higher and below the Ac1 temperature for 1200 seconds or longer.
([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au])-([Si] + [sol.Al])> 0.00% ... ( 1)
(2) In the method for manufacturing a non-directional electromagnetic steel plate according to (1) above, the steel material is in mass%.
Sn: 0.020 to 0.400%,
Sb: 0.020 to 0.400%,
P: 0.020 to 0.400%, and
Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: 0.0005 to 0.0100% in total
It may contain one or more selected from the group consisting of.
(3) In the method for manufacturing a non-directional electromagnetic steel plate according to (1) or (2) above,
In the finish annealing, it may be held for 10 to 1200 seconds in a temperature range of 600 ° C. or higher and lower than Ac1 temperature.
(4) In the method for manufacturing a non-directional electromagnetic steel plate according to any one of (1) to (3) above,
In the strain removing and annealing, it may be held for 1 hour or more in a temperature range of 750 ° C. or higher and lower than the Ac1 temperature.
(5) In the method for manufacturing a non-directional electromagnetic steel plate according to any one of (1) to (4) above,
In the first cold rolling step, cold rolling is performed at a cumulative reduction rate of 80 to 92%.
In the second cold rolling step, cold rolling may be performed at a cumulative reduction rate of 5 to 25%.
(6) In the method for manufacturing a non-directional electromagnetic steel plate according to any one of (1) to (5) above,
The intermediate annealing may be performed in a temperature range lower than the Ac1 temperature.
(7) In the method for manufacturing a non-directional electromagnetic steel plate according to any one of (1) to (6) above,
Both the finish annealing and the strain removal annealing may be performed.
Effect of the invention
[0009]
According to the above aspect according to the present invention, it is possible to provide a method for manufacturing a non-directional electromagnetic steel plate capable of obtaining excellent magnetic characteristics with an all-around average (omnidirectional average) in the plate surface.
According to the above preferred embodiment according to the present invention, it is possible to provide a non-directional electromagnetic steel plate which can obtain excellent magnetic characteristics with an all-around average (omnidirectional average) and has excellent workability.
Embodiment for carrying out the invention
[0010]
Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the configuration disclosed in the present embodiment, and various modifications can be made without departing from the gist of the present invention.
[0011]
First, a steel material used in the method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment (may be simply referred to as a steel material according to the present embodiment), and a method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment. The chemical composition of the non-directional electromagnetic steel plate (which may be simply referred to as the non-directional electromagnetic steel plate according to the present embodiment) produced by the above description will be described. In the following description, "%", which is a unit of the content of each element contained in the non-directional electromagnetic steel plate or steel material, means "mass%" unless otherwise specified. The numerical limit range described below with "to" in between includes the lower limit value and the upper limit value. Numerical values ​​marked "less than" or "greater than" do not fall within the numerical range.
[0012]
The non-directional electromagnetic steel plate and steel material according to the present embodiment have a chemical composition in which a ferrite-austenite transformation (hereinafter referred to as α-γ transformation) can occur. Specifically, in terms of mass%, C: 0.0100% or less, Si: 1.50 to 4.00%, sol. Al: 0.0001 to 1.000%, S: 0.0100% or less, N: 0.0100% or less, Mn, Ni, Co, Pt, Pb, Cu and Au: 2.50 to 5.00 in total %, Sn: 0.000 to 0.400%, Sb: 0.000 to 0.400%, P: 0.000 to 0.400%, and Mg, Ca, Sr, Ba, Ce, La, Nd. , Pr, Zn and Cd: Contains 0.0000-0.0100% in total and has a chemical composition with the balance consisting of Fe and impurities. Further, Mn, Ni, Co, Pt, Pb, Cu, Au, Si and sol. The Al content satisfies a predetermined condition described later.
[0013]
(C: 0.0100% or less)
C increases the iron loss of the non-directional electromagnetic steel plate and causes magnetic aging. Therefore, the lower the C content, the more preferable. Such a phenomenon is remarkable when the C content exceeds 0.0100%. Therefore, the C content is set to 0.0100% or less. The reduction of the C content also contributes to the uniform improvement of the magnetic characteristics in the all-around average in the plate surface. Therefore, the C content is preferably 0.0060% or less, more preferably 0.0040% or less, and even more preferably 0.0020% or less.
Although the lower limit of the C content is not particularly limited, it is preferably 0.0005% or more in consideration of the cost of decarburization treatment at the time of refining.
[0014]
(Si: 1.50-4.00%)
Si increases electrical resistance to reduce eddy current loss, reduces iron loss in non-directional electromagnetic steel sheets, and increases yield ratio to improve workability during punching into iron cores. .. If the Si content is less than 1.50%, these effects cannot be sufficiently obtained. Therefore, the Si content is 1.50% or more. The Si content is preferably 2.00% or more, more preferably 2.50% or more.
On the other hand, if the Si content exceeds 4.00%, the magnetic flux density of the non-directional electromagnetic steel plate may decrease, the workability during punching may decrease due to an excessive increase in hardness, or cold rolling may become difficult. do. Therefore, the Si content is set to 4.00% or less. The Si content is preferably 3.50% or less, more preferably 3.30% or less.
[0015]
(Sol.Al: 0.0001 to 1.000%)
Sol. Al increases the electrical resistance, reduces the eddy current loss, and reduces the iron loss of the non-directional electromagnetic steel plate. sol. Al also contributes to the improvement of the relative magnitude of the magnetic flux density B50 with respect to the saturated magnetic flux density. Here, the magnetic flux density B50 is the magnetic flux density in a magnetic field of 5000 A / m. sol. If the Al content is less than 0.0001%, these effects cannot be sufficiently obtained. Al also has the effect of promoting desulfurization in steelmaking. Therefore, sol. The Al content is 0.0001% or more. sol. The Al content is preferably 0.005% or more, more preferably more than 0.100%, still more preferably 0.200% or more, still more preferably 0.300% or more.
On the other hand, sol. When the Al content exceeds 1.000%, the magnetic flux density of the non-directional electromagnetic steel plate is lowered, the yield ratio is lowered, and the workability at the time of punching is lowered. Therefore, sol. The Al content is 1.000% or less. sol. The Al content is preferably 0.500% or less, more preferably 0.400% or less.
In this embodiment, sol. Al means acid-soluble Al, and indicates solid-dissolved Al existing in steel in a solid-dissolved state.
[0016]
(S: 0.0100% or less)
S is not an essential element to be contained, but is an element contained as an impurity in steel, for example. S inhibits recrystallization and growth of crystal grains in quenching due to the precipitation of fine MnS. When the recrystallization and the growth of crystal grains are inhibited, the iron loss of the non-directional electromagnetic steel plate increases and the magnetic flux density decreases. Therefore, the lower the S content, the more preferable. The increase in iron loss and the decrease in magnetic flux density due to the inhibition of such recrystallization and grain growth are remarkable when the S content exceeds 0.0100%. Therefore, the S content is 0.0100% or less. The S content is preferably 0.0060% or less, more preferably 0.0040% or less.
Although the lower limit of the S content is not particularly limited, it is preferably 0.0003% or more in consideration of the cost of desulfurization treatment at the time of refining.
[001 7]
(N: 0.0100% or less)
Similar to C, N deteriorates the magnetic properties of the non-directional electromagnetic steel plate, so the lower the N content, the more preferable. Therefore, the N content is 0.0100% or less. The N content is preferably 0.0050% or less, more preferably 0.0030% or less.
Although the lower limit of the N content is not particularly limited, it is preferably 0.0010% or more in consideration of the cost of denitrification treatment at the time of refining.
[0018]
(Mn, Ni, Co, Pt, Pb, Cu and Au: 2.50 to 5.00% in total)
Since Mn, Ni, Co, Pt, Pb, Cu and Au are elements necessary for causing α-γ transformation, at least one of these elements is contained in an amount of 2.50% or more. It is not necessary to contain all of these elements, and any one of them may have a content of 2.50% or more. The total content of these elements is preferably 3.00% or more.
On the other hand, if the total content of these elements exceeds 5.00%, the cost will increase and the magnetic flux density of the non-directional electromagnetic steel plate may decrease. Therefore, the total content of these elements shall be 5.00% or less. The total content of these elements is preferably 4.50% or less.
The total of Mn, Ni, Co, Pt, Pb, Cu and Au can be obtained by calculating the total content of Mn, Ni, Co, Pt, Pb, Cu and Au.
[0019]
The non-directional electromagnetic steel plate and steel material according to the present embodiment have a chemical composition that further satisfies the following conditions as conditions under which α-γ transformation can occur. That is, the Mn content (% by mass) is [Mn], the Ni content (% by mass) is [Ni], the Co content (% by mass) is [Co], and the Pt content (% by mass) is [Pt]. Pb content (% by mass) is [Pb], Cu content (% by mass) is [Cu], Au content (% by mass) is [Au], Si content (% by mass) is [Si], sol. The Al content (% by mass) was changed to [sol. Al], the following equation (1) is satisfied.
([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au])-([Si] + [sol.Al])> 0.00% ... ( 1)
[0020]
If the above equation (1) is not satisfied, the α-γ transformation does not occur, so that the magnetic flux density of the non-directional electromagnetic steel plate becomes low. Therefore, the left side of Eq. (1) is set to exceed 0.00%. The left side of the equation (1) is preferably 0.30% or more, more preferably 0.50% or more.
The upper limit of the left side of the equation (1) is not particularly limited, but may be 2.00% or less, or 1.00% or less.
[0021]
The balance of the chemical composition of the non-directional electromagnetic steel plate and the steel material according to the present embodiment consists of Fe and impurities. As impurities, those contained in raw materials such as ore and scrap, those contained in the manufacturing process, or those manufactured by the method for manufacturing a non-directional electromagnetic steel sheet according to the present embodiment adversely affect the characteristics of the non-directional electromagnetic steel sheet. An example is one that is permissible to the extent that it does not reach.
[0022]
The non-directional electromagnetic steel plate and steel material according to the present embodiment may contain the following elements as optional elements in addition to a part of Fe. When the following optional elements are not contained, the lower limit of the content is 0%. Hereinafter, each arbitrary element will be described in detail.
[0023]
(Sn: 0.000 to 0.400%, Sb: 0.000 to 0.400%, P: 0.000 to 0.400%)
Sn and Sb improve the texture after cold rolling and recrystallization, thereby improving the magnetic flux density of the non-directional electromagnetic steel plate. Therefore, these elements may be contained as needed. In order to surely obtain the above effect, it is preferable that the content of even one of Sn and Sb is 0.020% or more. On the other hand, if Sn and Sb are excessively contained, the steel becomes brittle. Therefore, both the Sn content and the Sb content are set to 0.400% or less.
[0024]
Further, P may be contained in order to secure the hardness of the steel plate after recrystallization. In order to surely obtain this effect, it is preferable that the P content is 0.020% or more. On the other hand, excessive inclusion of P causes brittleness of the steel. Therefore, the P content is 0.400% or less.
[0025]
(Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: 0.0000 to 0.0100% in total)
Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd react with S in the molten steel to form sulfides and / or acid sulfides during casting of the molten steel. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd may be collectively referred to as "coarse precipitate-forming element".
[0026]
The particle size of the precipitate of the coarse precipitate-forming element is about 1 to 2 μm, which is much larger than the particle size of the fine precipitate (about 100 nm) such as MnS, TiN, and AlN. These fine precipitates adhere to the precipitates of the coarse precipitate-forming elements, and it becomes difficult to inhibit the recrystallization and the growth of crystal grains in the quenching such as intermediate quenching. In order to sufficiently obtain these effects, the total amount of coarse precipitate-forming elements is preferably 0.0005% or more. In addition, in order to sufficiently obtain the above action, it is not necessary to contain all of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd, and the content of any one of them is high. It is preferably 0.0005% or more.
[0027]
On the other hand, if the total amount of coarse precipitate-forming elements exceeds 0.0100%, the total amount of sulfide and / or acid sulfide becomes excessive, and recrystallization and growth of crystal grains in baking such as intermediate baking are inhibited. Therefore, the total content of the coarse precipitate-forming element is 0.0100% or less.
The total content of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd is the content of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd. It is obtained by calculating the total value of.
[0028]
The chemical composition of the non-directional electromagnetic steel plate and the steel material according to the present embodiment may be measured by a general analysis method. For example, it may be measured by using ICP-AES (Industrial Coupled Plusma-Atomic Emission Spectrometry) or emission spectroscopic analysis (OES: Optical Mission Spectropy). In addition, C and S may be measured by using the combustion-infrared absorption method, and N may be measured by using the inert gas melting-heat conductivity method. sol. Al may be measured by ICP-AES using a filtrate obtained by heat-decomposing a sample with an acid.
[0029]
Next, the texture of the non-directional electromagnetic steel plate according to the present embodiment will be described. The details of the manufacturing method will be described later, but the non-directional electromagnetic steel sheet according to the present embodiment has a chemical composition capable of causing α-γ transformation, and has a first cold rolling, an intermediate quenching, and a second cold rolling (2). It has a structure in which {100} crystal grains have grown by refining the structure by performing finish annealing or strain removal annealing under desired conditions (skin pass rolling). As a result, the non-directional electromagnetic steel plate according to the present embodiment has, for example, an integrated strength of 5 or more in the {100} <011> orientation, and a magnetic flux density B50 in the 45 ° direction with respect to the rolling direction is particularly high. In the non-directional electromagnetic steel plate according to the present embodiment, the magnetic flux density increases in a specific direction as described above, but a high magnetic flux density can be obtained on the whole circumference average in the plate surface. When the integrated strength in the {100} <011> orientation is less than 5, the integrated strength in the {111} <112> orientation, which reduces the magnetic flux density, becomes high, and the magnetic flux density decreases as a whole.
[0030]
The integrated intensity of the {100} <011> orientation can be measured by the X-ray diffractometry or the electron beam backscatter diffusion (EBSD) method. Since the angle of reflection of X-ray and electron beam from the sample differs depending on the crystal orientation, the crystal orientation intensity can be obtained from the reflection intensity or the like with reference to the random orientation sample.
[0031]
Next, the magnetic characteristics of the non-directional electromagnetic steel plate according to the present embodiment will be described. The non-directional electromagnetic steel plate according to the present embodiment has the best magnetic characteristics in two directions in which the smaller angle of the rolling direction is 45 °. On the other hand, the magnetic characteristics are the worst in the two directions where the angles formed with the rolling direction are 0 ° and 90 °. Here, the 45 ° is a theoretical value, and it may not be easy to match it with 45 ° in actual manufacturing. Therefore, theoretically, if the direction in which the magnetic characteristics are the best is the two directions in which the smaller angle of the rolling direction is 45 °, the actual non-directional electromagnetic steel plate is said to be 45. ° shall include those that do not (exactly) match 45 °. This is the same at 0 ° and 90 °.
[0032]
In addition, theoretically, the magnetic characteristics in the two directions having the best magnetic characteristics are the same, but in actual manufacturing, it may not be easy to make the magnetic characteristics in the two directions the same. Therefore, theoretically, if the magnetic properties in the two directions having the best magnetic properties are the same, the same includes those that are not (exactly) the same. This is the same in the two directions with the worst magnetic properties.
[0033]
Note that the above-mentioned angles are expressed assuming that angles in both clockwise and counterclockwise directions have positive values. When the clockwise direction is a negative direction and the counterclockwise direction is a positive direction, the two directions in which the smaller angle of the above-mentioned rolling directions is 45 ° are the above-mentioned rolling directions. Of the angles to be formed, the angle with the smaller absolute value is 45 ° and −45 ° in two directions.
[0034]
The two directions in which the smaller angle of the above-mentioned rolling directions is 45 ° can be described as the two directions in which the angles formed with the rolling directions are 45 ° and 135 °.
[0035]
When the magnetic flux density of the non-directional electromagnetic steel plate according to the present embodiment is measured, the magnetic flux density B50 in the 45 ° direction with respect to the rolling direction is 1.700 T or more. Further, the magnetic flux density B50 of the all-around average (omnidirectional average) in the plate surface is 1.650 T or more. In the non-directional electromagnetic steel plate according to the present embodiment, the magnetic flux density in the 45 ° direction with respect to the rolling direction is high, but a high magnetic flux density can be obtained even in the all-around average (omnidirectional average) in the plate surface.
[0036]
The magnetic flux density B50 is obtained by cutting out a 55 mm square sample from a non-directional electromagnetic steel plate from 45 °, 0 °, etc. with respect to the rolling direction, and using a single plate magnetic measuring device to determine the magnetic flux density in a magnetic field of 5000 A / m. Obtained by measuring. The magnetic flux density B50 in the all-around average (omnidirectional average) is obtained by calculating the average value of the magnetic flux densities of 0 °, 45 °, 90 ° and 135 ° with respect to the rolling direction.
[0037]
Iron loss W10 / 400 changes depending on the thickness of the non-directional electromagnetic steel plate. As the thickness of the non-directional electromagnetic steel plate decreases, the iron loss W10 / 40 decreases.
In the non-directional electromagnetic steel plate according to the present embodiment, when the plate thickness is 0.30 to 0.40 mm, the iron loss W10 / 400 is 20.00 W / kg or less. When the strain removing and annealing described later is performed, the iron loss W10 / 400 is further reduced, and when the plate thickness is 0.30 to 0.40 mm, it becomes 15.20 W / kg or less.
[0038]
Iron loss W10 / 400 occurs when a sample collected from a non-directional electromagnetic steel plate is applied with an AC magnetic field of 400 Hz so that the maximum magnetic flux density becomes 1.0 T using a single plate magnetic measuring device. It is obtained by measuring the energy loss (W / kg) of the whole circumference average.
[0039]
Next, a method for manufacturing the non-directional electromagnetic steel plate according to the present embodiment will be described. In the method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment, any of hot rolling, first cold rolling, intermediate quenching, second cold rolling (skin pass rolling), and finish annealing or strain removal annealing. Do one or both.
[0040]
Specifically, in the method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment, a steel material having the above-mentioned chemical composition is hot-rolled and wound in a temperature range of more than 250 ° C and 550 ° C or less. And the process of obtaining hot rolled steel plate The step of performing the first cold rolling on the hot rolled steel plate and
The process of performing intermediate annealing after the first cold rolling and
The process of performing the second cold rolling after the intermediate quenching and
It has a step of performing one or both of finish annealing and strain removal annealing after the second cold rolling.
Perform the final pass of finish rolling during hot rolling in a temperature range above Ar1 temperature,
In the finish annealing, hold for 2 hours or less in a temperature range below Ac1 temperature.
In the strain removing and annealing, the temperature is maintained at 600 ° C. or higher and below the Ac1 temperature for 1200 seconds or longer.
[0041]
In the method for producing a non-directional electromagnetic steel plate according to the present embodiment, in the finish annealing, the product may be held in a temperature range of 600 ° C. or higher and lower than the Ac1 temperature for 10 to 1200 seconds.
Further, in the strain removing and annealing, the strain may be maintained in a temperature range of 750 ° C. or higher and lower than the Ac1 temperature for 1 hour or longer.
[0042]
In the method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment, in the first cold rolling step, cold rolling is performed at a cumulative reduction rate of 80 to 92%.
In the second cold rolling step, cold rolling may be performed with a cumulative reduction rate of 5 to 25%.
[0043]
In the method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment, the intermediate annealing may be performed in a temperature range lower than the Ac1 temperature.
[0044]
In the method for manufacturing a non-directional electromagnetic steel plate according to the present embodiment, both the finish annealing and the strain removal annealing may be performed.
Below, each process will be explained in detail.
[0045]
First, the steel material having the above-mentioned chemical composition is heated and hot-rolled. The steel material is, for example, a slab manufactured by ordinary continuous casting. Rough rolling and finish rolling of hot rolling are performed in the temperature range of γ range (Ar1 temperature or higher). That is, hot rolling is performed so that the finishing temperature of the finish rolling (the exit side temperature of the final pass) is Ar1 temperature or higher. As a result, austenite is transformed into ferrite by the subsequent cooling, and the crystal structure becomes finer. When cold rolling is performed in a state where the crystal structure is refined, bulging is likely to occur, and {100} crystal grains, which are normally difficult to grow, can be easily grown. The upper limit of the finishing temperature is not particularly limited, but may be, for example, 950 ° C. or lower.
The heating temperature of the steel material may be, for example, 1100 to 1250 ° C. so that the finish temperature of the finish rolling is Ar1 temperature or higher.
[0046]
Further, in the present embodiment, the winding is performed in a temperature range of more than 250 ° C and 550 ° C or less. It is preferably 530 ° C. or lower, more preferably 500 ° C. or lower, and even more preferably 480 ° C. or lower. Cooling to a temperature range of 550 ° C or lower completes the transformation from austenite to ferrite.
When the winding temperature is 250 ° C or less, recrystallization does not occur during winding and processed grains remain, so that the crystal structure is not refined. Therefore, the above-mentioned winding temperature is set up to a temperature range of more than 250 ° C. It is preferably 300 ° C. or higher and 400 ° C. or higher.
[0047]
After that, if necessary, the coil may be rewound and pickled. After the coil is rewound or pickled, the hot-rolled steel plate is subjected to the first cold rolling.
[0048]
In the first cold rolling, the cumulative reduction rate is preferably 80 to 92%. The higher the cumulative reduction rate, the easier it is for {100} crystal grains to grow due to subsequent bulging, but it becomes more difficult to wind the hot-rolled steel plate and it becomes more difficult to operate. By setting the cumulative reduction rate in the first cold rolling within the above range, the growth of {100} crystal grains due to the subsequent bulging can be preferably controlled.
[0049]
The cumulative reduction rate referred to here is the plate thickness of the hot-rolled steel plate before the first cold rolling: t 0 and the plate thickness of the steel plate after the first cold rolling (cold-rolled steel plate) t 1. It is expressed as (1-t 1 / t 0) × 100 (%) using and.
[0050]
After the first cold rolling, intermediate annealing is performed. In the present embodiment, it is preferable to perform intermediate annealing in a temperature range in which ferrite does not transform into austenite. That is, it is preferable to perform the intermediate annealing in a temperature range lower than the Ac1 temperature. By performing intermediate annealing under such conditions, bulging occurs and {100} crystal grains are likely to grow. Further, the annealing time of intermediate annealing (holding time in a temperature range lower than Ac1 temperature) is preferably 5 to 60 seconds. Further, the intermediate annealing is preferably performed at 600 ° C. or higher, and is preferably performed in a non-oxidizing atmosphere.
[0051]
After intermediate annealing, perform a second cold rolling (skin pass rolling). When cold rolling is performed in a state where bulging has occurred as described above, {100} crystal grains are further grown starting from the portion where bulging has occurred. The cumulative reduction rate of the second cold rolling (skin pass rolling) is preferably 5 to 25%.
[0052]
The cumulative reduction rate referred to here is (1-t) using the plate thickness of the steel plate before the second cold rolling: t 0 and the plate thickness of the steel plate after the second cold rolling t 1. It is expressed as 1 / t 0) × 100 (%).
[0053]
{100} <011> Crystal grains are less likely to accumulate strain, and {111} <112> crystal grains are likely to accumulate strain. By performing the second cold rolling and then baking, the {100} <011> crystal grains with less strain erode the {111} <112> crystal grains by using the difference in strain as a driving force. As a result, {100} crystal grains grow further. This silkworm erosion phenomenon generated by the difference in strain as a driving force is called strain-induced grain boundary movement (SIBM).
[0054]
By setting the cumulative reduction rate in the second cold rolling to 5% or more, a sufficient amount of strain can be secured, and strain-induced grain boundary movement (SIBM) occurs in the subsequent annealing, and {100} <011> crystal grains. Can grow significantly.
Further, by setting the cumulative reduction rate in the second cold rolling to 25% or less, it is possible to prevent the strain amount from becoming too large. As a result, it is possible to suppress the generation of recrystallized nucleation in which new crystal grains are generated from the {111} <112> crystal grains. In this recrystallized nucleation generation, most of the crystal grains generated are {111} <112> crystal grains, so that the magnetic properties of the non-directional electromagnetic steel plate may deteriorate when the recrystallized nuclei generation occurs.
[0055]
When controlling the non-directional electromagnetic steel plate according to the present embodiment so as to have a desired strain distribution, the cumulative reduction rate (%) of the first cold rolling is Rm, and the second cold rolling (skin pass rolling). ), When the cumulative reduction rate (%) is Rs, it is preferable that 86 orientation is significantly reduced, and the magnetic properties of the non-directional electromagnetic steel plate are deteriorated. Therefore, the holding temperature in strain removal and annealing is set to be less than the Ac1 temperature.
Further, even if the temperature is maintained in a temperature range of less than 600 ° C., the above-mentioned strain releasing effect and {100} crystal grain growth effect cannot be obtained. Therefore, the holding temperature in strain removal and annealing is set to 600 ° C. or higher.
[0064]
For strain removal and annealing, it is preferable to keep the temperature in a temperature range of 750 ° C. or higher and lower than Ac1 temperature for 1 hour or longer. By holding for 1 hour or more in a temperature range of 750 ° C. or higher, the above-mentioned strain releasing effect and {100} crystal grain growth effect can be obtained more reliably.
The upper limit of the holding time is not particularly limited, but may be, for example, 4 hours or less and 3 hours or less.
[0065]
By the above method, the non-directional electromagnetic steel plate according to the present embodiment can be manufactured.
[0066]
In this embodiment, the Ar1 temperature is obtained from the change in thermal expansion of the steel material (steel plate) being cooled at an average cooling rate of 1 ° C./sec. Further, in the present embodiment, the Ac1 temperature is obtained from the change in thermal expansion of the steel material (steel plate) being heated at an average heating rate of 1 ° C./sec.
[0067]
The non-directional electromagnetic steel plate according to the present embodiment is suitably applied to, for example, the iron core of a rotary electric machine. In this case, individual flat plate-shaped thin plates are cut out from the non-directional electromagnetic steel plate according to the present embodiment, and these flat plate-shaped thin plates are appropriately laminated to produce an iron core used for a rotary electric machine. Since a non-directional electromagnetic steel plate having excellent magnetic properties is applied to this iron core, iron loss is low. As a result, a rotary electric machine having excellent torque can be obtained.
Example
[0068]
Next, the method for manufacturing the non-directional electromagnetic steel plate according to the embodiment of the present invention will be specifically described with reference to examples. The examples shown below are merely examples of the method for manufacturing a non-directional electromagnetic steel sheet according to an embodiment of the present invention, and the method for manufacturing a non-directional electromagnetic steel sheet according to the present invention is limited to the following examples. is not.
[0069]
(First example)
By casting molten steel, slabs with the chemical composition shown in Table 1 below were prepared. The left side of the formula in the table represents the value of the left side of the above-mentioned formula (1). Then, the prepared slab was heated to 1150 ° C.By performing hot rolling under the conditions shown in Table 2, a hot rolled steel plate having a plate thickness of 2.5 mm was obtained.
[0070]
The finish temperature of the finish rolling was 800 ° C., which was higher than the Ar1 temperature of all the steel plates.
[0071]
Next, the obtained hot-rolled steel sheet was pickled to remove scale. Then, a steel plate (cold-rolled steel plate) was obtained by performing the first cold rolling until the plate thickness became 0.385 mm at a cumulative reduction rate of 85%. The obtained steel plate was heated and subjected to intermediate annealing in a non-oxidizing atmosphere at 700 ° C., which is a temperature lower than the Ac1 temperature of all the steel plates, and held for 5 to 60 seconds. Then, a second cold rolling (skin pass rolling) was performed until the plate thickness became 0.35 mm at a cumulative reduction rate of 9%.
[0072]
The Ac1 temperature of all the examples shown in Table 1 was about 850 ° C. The Ar1 temperature was determined from the change in thermal expansion of the steel plate being cooled at an average cooling rate of 1 ° C./sec, and the Ac1 temperature was determined from the change in thermal expansion of the steel plate being heated at an average heating rate of 1 ° C./sec.
[0073]
After performing the second cold rolling (skin pass rolling), finish annealing was performed. Table 2 shows the reached temperature (holding temperature) and holding time at this time.
[0074]
In order to evaluate the workability of the non-directional electromagnetic steel plate, a test was conducted to evaluate the punching accuracy after finish baking. In the test, the shape of the punched material was measured using a punching mold of 3 mm × 50 mm. The punching was performed so that the long side direction was parallel to the rolling direction of the steel plate. In the shape measurement, the long side and the short side of the punched material were measured, and one end in the long side direction was pressed with a finger to measure the amount of lift of the other end.
[0075]
After finish annealing, strain removal annealing was performed, which was held at 800 ° C. for 2 hours. After strain removal and annealing, the magnetic flux density B50 was measured using a single plate magnetic measuring device. A 55 mm square sample was sampled in two directions of 0 ° and 45 ° with respect to the rolling direction of the steel plate, and the magnetic flux density B50 was measured. The magnetic flux density in the 45 ° direction with respect to the rolling direction was defined as the magnetic flux density B50 in the 45 ° direction. By calculating the average values ​​of the magnetic flux densities of 0 °, 45 °, 90 ° and 135 ° with respect to the rolling direction, the all-around average of the magnetic flux density B50 was obtained.
[0076]
In addition, the energy loss (W / kg) of the whole circumference average generated when an AC magnetic field of 400 Hz is applied to a sample collected from a non-directional electromagnetic steel plate so that the maximum magnetic flux density becomes 1.0 T is measured. As a result, iron loss W10 / 400 was obtained.
[0077]
[table 1]

[0078]
[Table 2]

[0079]
The underline in Table 2 shows the conditions outside the scope of the present invention. No. which is an example of the present invention. 101-No. 110, No. 112-No. 114, No. 120-No. 126, No. 128, No. 129 and No. 132 has excellent workability (good dimensional accuracy after punching, almost no floating amount), and excellent magnetic characteristics in both the 45 ° direction and the all-around average (high magnetic flux density B50 and low iron loss W10 / 400). ) Had. In addition, No. 1 which is an example of the present invention. 115 to 117 have excellent magnetic properties, but their workability is slightly inferior to that of other examples of the present invention.
[0080] [0080]
On the other hand, No. which is a comparative example. Since the holding temperature of 111 was higher than the Ac1 temperature during finish baking, the dimensional accuracy deteriorated and the magnetic flux density also deteriorated. In addition, No. 118, No. 119, No. 127 and No. In 130, the winding temperature was not appropriate, so that the magnetic flux density decreased and / or the iron loss increased.
[0081]
(Second example)
By casting molten steel, slabs with the chemical composition shown in Table 3 below were prepared. The left side of the formula in the table represents the value of the left side of the above-mentioned formula (1). Then, the produced slab was heated to 1150 ° C. and hot-rolled under the conditions shown in Table 4 to obtain a hot-rolled steel plate having a plate thickness of 2.5 mm.
[0082]
After finish rolling, it was water-cooled to 500 ° C, and then the hot-rolled steel plate was wound up.
The finish temperature of the finish rolling was 800 ° C., which was higher than the Ar1 temperature of all the steel plates.
[0083]
Next, the obtained hot-rolled steel sheet was pickled to remove scale. Then, a steel plate (cold-rolled steel plate) was obtained by performing the first cold rolling until the plate thickness became 0.385 mm at a cumulative reduction rate of 85%. The obtained steel plate was heated and subjected to intermediate annealing in a non-oxidizing atmosphere, which was held at 700 ° C. for 5 to 60 seconds, which is a temperature lower than the Ac1 temperature of all the steel plates. Then, a second cold rolling (skin pass rolling) was performed until the plate thickness became 0.35 mm at a cumulative reduction rate of 9%.
[0084]
After the second cold rolling (skin pass rolling), finish annealing was performed in which all the steel plates were held at 700 ° C., which is lower than the Ac1 temperature, for 30 seconds. Then, the processability was evaluated and the magnetic flux density B50 and the iron loss W10 / 400 were measured by the same method as in the first embodiment. The Ar1 temperature and the Ac1 temperature were measured by the same method as in the first embodiment.
[0085]
[Table 3]

[0086]
[Table 4]

[0087]
No. 201-No. All of 216 are examples of the present invention, and all of them have excellent workability (good dimensional accuracy after punching, small floating amount) and excellent magnetic characteristics (high magnetic flux density B50 and low iron loss W10 / 400). ) Had. In particular, No. 202-No. 204 is No. 201, No. 205-No. The magnetic flux density B50 was higher than that of 214. No. 205-No. 214 is No. 201-No. The iron loss W10 / 400 was lower than that of 204. No. 215 and 216 are No. The iron loss W10 / 400 was lower than that of 202, but the magnetic flux density B50 was lower.
[0088]
(Third example)
By casting molten steel, slabs with the chemical composition shown in Table 5 below were prepared. The left side of the formula in the table represents the value of the left side of the above-mentioned formula (1). Then, the produced slab was heated to 1150 ° C. and hot-rolled under the conditions shown in Table 6 to obtain a hot-rolled steel plate having a plate thickness of 2.5 mm.
[0089]
The finish temperature of the finish rolling was 800 ° C., which was higher than the Ar1 temperature of all the steel plates.
[0090]
Next, the obtained hot-rolled steel sheet was pickled to remove scale. Then, a steel plate (cold-rolled steel plate) was obtained by performing the first cold rolling until the plate thickness became 0.385 mm at a cumulative reduction rate of 85%. The obtained steel plate was heated and subjected to intermediate annealing in a non-oxidizing atmosphere at 700 ° C., which is a temperature lower than the Ac1 temperature of all the steel plates, and held for 5 to 60 seconds. Then, a second cold rolling (skin pass rolling) was performed until the plate thickness became 0.35 mm at a cumulative reduction rate of 9%.
[0091]
The Ac1 temperature of all the examples shown in Table 5 was about 850 ° C.
[0092]
After performing the second cold rolling (skin pass rolling), finish annealing was performed. Table 6 shows the reached temperature (holding temperature) and holding time at this time. Then, the processability was evaluated and the magnetic flux density B50 and the iron loss W10 / 400 were measured by the same method as in the first embodiment. The Ar1 temperature and the Ac1 temperature were measured by the same method as in the first embodiment.
No strain removal and annealing was performed in this example.
[0093]
[Table 5]

[0094]
[Table 6]

[0095]
The underline in Table 6 shows the conditions outside the scope of the present invention. No. which is an example of the present invention. 301-No. 310, No. 312-No. 314, No. 320 and No. 321 has excellent workability (good dimensional accuracy after punching, almost no floating amount), and excellent magnetic characteristics in both the 45 ° direction and the all-around average (high magnetic flux density B50 and low iron loss W10 / 400). ) Had. In addition, No. 1 which is an example of the present invention. The magnetic properties of 315 to 317 were good, but the processability was slightly inferior to that of other examples of the present invention.
[0096]
On the other hand, No. which is a comparative example. Since the holding temperature of 311 at the time of finish baking was higher than the Ac1 temperature, the dimensional accuracy deteriorated and the magnetic flux density also deteriorated. In addition, No. 318 and No. In 319, the winding temperature was not appropriate, so that the magnetic flux density decreased and the iron loss increased.
[0097]
(Fourth example)
By casting molten steel, slabs with the chemical composition shown in Table 7 below were prepared. The left side of the formula in the table represents the value of the left side of the above-mentioned formula (1). Then, the produced slab was heated to 1150 ° C. and hot-rolled under the conditions shown in Table 8 to obtain a hot-rolled steel plate having a plate thickness of 2.5 mm.
[0098]
The finish temperature of the finish rolling was 800 ° C., which was higher than the Ar1 temperature of all the steel plates.
[0099]
Next, the obtained hot-rolled steel sheet was pickled to remove scale. Then, a steel plate (cold-rolled steel plate) was obtained by performing the first cold rolling until the plate thickness became 0.385 mm at a cumulative reduction rate of 85%. The obtained steel plate was heated and subjected to intermediate annealing in a non-oxidizing atmosphere at 700 ° C., which is a temperature lower than the Ac1 temperature of all the steel plates, and held for 5 to 60 seconds. Then, a second cold rolling (skin pass rolling) was performed until the plate thickness became 0.35 mm at a cumulative reduction rate of 9%.
[0100]
The Ac1 temperature of all the examples shown in Table 7 was about 850 ° C.
[0101]
After performing the second cold rolling (skin pass rolling), the workability was evaluated by the same method as in the first embodiment.
No finish baking was performed in this example.
[0102]
After the workability evaluation test, strain removal and annealing was performed by holding at 800 ° C. for 2 hours. After the strain removal and annealing, the magnetic flux density B50 and the iron loss W10 / 400 were measured by the same method as in the first embodiment. The Ar1 temperature and the Ac1 temperature were measured by the same method as in the first embodiment.
[0103]
[Table 7]

[0104]
[Table 8]

[0105]
The underline in Table 8 shows the conditions outside the scope of the present invention. No. which is an example of the present invention. 401-No. 408, No. 411 and No. The 412 had good dimensional accuracy after punching, but a slight amount of levitation occurred. In addition, it had excellent magnetic characteristics (high magnetic flux density B50 and low iron loss W10 / 400) in both the 45 ° direction and the all-around average.
[0106]
On the other hand, No. which is a comparative example. 409 and No. Since the winding temperature of 410 was not appropriate, the magnetic flux density decreased and the iron loss increased.
The scope of the claims
[Claim 1]
By mass%,
C: 0.0100% or less,
Si: 1.50-4.00%,
Sol. Al: 0.0001 to 1.000%,
S: 0.0100% or less,
N: 0.0100% or less,
Mn, Ni, Co, Pt, Pb, Cu and Au: 2.50 to 5.00% in total,
Sn: 0.000 to 0.400%,
Sb: 0.000 to 0.400%,
P: 0.000 to 0.400%, and
Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: Containing 0.0000 to 0.0100% in total,
By mass%, Mn content is [Mn], Ni content is [Ni], Co content is [Co], Pt content is [Pt], Pb content is [Pb], and Cu content is [ Cu], Au content is [Au], Si content is [Si], sol. Al content is [sol. When expressed as [Al], the following equation (1) is satisfied.
A process of hot-rolling a steel material having a chemical composition in which the balance is composed of Fe and impurities and winding it in a temperature range of more than 250 ° C and 550 ° C or less to obtain a hot-rolled steel plate.
The process of performing the first cold rolling on the hot rolled steel plate and
The process of performing intermediate annealing after the first cold rolling and
The process of performing the second cold rolling after the intermediate quenching and
It has a step of performing one or both of finish annealing and strain removal annealing after the second cold rolling.
Perform the final pass of finish rolling during hot rolling in a temperature range above Ar1 temperature,
In the finish annealing, hold for 2 hours or less in a temperature range below Ac1 temperature.
In the strain removal annealing, 1 in the temperature range of 600 ° C or higher and lower than Ac1 temperature.Hold for 200 seconds or more
A method for manufacturing a non-directional electromagnetic steel plate.
([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au])-([Si] + [sol.Al])> 0.00% ... ( 1)
[Claim 2]
The steel material is by mass%
Sn: 0.020 to 0.400%,
Sb: 0.020 to 0.400%,
P: 0.020 to 0.400%, and
Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: 0.0005 to 0.0100% in total
The method for manufacturing a non-directional electromagnetic steel sheet according to claim 1, wherein the method comprises one or more selected from the group consisting of.
[Claim 3]
The method for manufacturing a non-directional electromagnetic steel plate according to claim 1 or 2, wherein the finish annealing is held in a temperature range of 600 ° C. or higher and lower than Ac1 temperature for 10 to 1200 seconds.
[Claim 4]
The method for manufacturing a non-directional electromagnetic steel plate according to any one of claims 1 to 3, wherein the strain-removing annealing is held in a temperature range of 750 ° C. or higher and lower than Ac1 temperature for 1 hour or longer.
[Claim 5]
In the first cold rolling step, cold rolling is performed at a cumulative reduction rate of 80 to 92%.
The non-directional electromagnetic steel sheet according to any one of claims 1 to 4, wherein in the second cold rolling step, cold rolling is performed at a cumulative reduction rate of 5 to 25%. Production method.
[Claim 6]
The method for manufacturing a non-directional electromagnetic steel plate according to any one of claims 1 to 5, wherein the intermediate annealing is performed in a temperature range lower than the Ac1 temperature.
[Claim 7]
The method for manufacturing a non-directional electromagnetic steel plate according to any one of claims 1 to 6, wherein both the finish annealing and the strain removal annealing are performed.