JPS60238421A - Production of high tensile non-oriented electrical steel sheet - Google Patents

Abstract

PURPOSE:To obtain a titled steel sheet exhibiting high tensile strength and having excellent soft magnetic characteristics such as low high-frequency iron loss and low coercive force by hot-rolling a blank slab of a silicon steel having a specific component compsn. to a hot-rolled steel sheet then subjecting repeatedly the sheet to warm-rolling in a prescribed temp. range to form the sheet into a final thickness and subjecting such sheet to final finish annealing. CONSTITUTION:The blank slab of a silicon steel contg., by weight %, 3.5-7.0 as well as <=20.0 1 kinds among 0.05-3.0 Ti, 0.05-3.0 Mo, 0.1-11.5 Mn, 0.1-20.0 Ni, 0.5-20.0 Co and 0.5-13.0 Al is treated in the following way. The slab is hot-rolled at 800-1,350 deg.C and is thereafter subjected to normalizing annealing at 750-1,100 deg.C according to need. The hot-rolled sheet after annealing is subjected repeatedly to warm-rolling at 100-600 deg.C and is rolled down to 0.1-0.35mm. final thickness. The steel sheet rolled to the final thickness is annealed at 850-1,200 deg.C by which the high-tensile non-oriented electrical steel sheet satisfying >=50kg/mm.<2> tensile strength, >=1.5T magnetic flux density B50 and <=100W/kg iron loss W10/ 1,000 is obtd.

Description

[Detailed Description of the Invention] Technical field The technical content described in this specification regarding the method for manufacturing high tensile strength non-oriented electrical steel sheets, adjustment of the component composition of non-oriented electrical steel sheets, and rolling processing after hot rolling. It is related to improving the tensile strength without causing deterioration of soft magnetic properties by adding innovations to the magnetic properties.

Technical Background In recent years, there have been remarkable developments in electrical and electronic equipment, including electronics, and one of the factors that will further promote such development is the increase in the high-speed motion of rotating equipment. This is because the rotation speed required for conventional rotating equipment was 100,000 rpm at most.
It was only a matter of time, but I was able to do so.

By the way, in order to realize high-speed rotation in such rotating equipment, it is a matter of course that the development of materials that can withstand such high-speed rotation becomes a problem. In other words, when the rotation speed of the rotor of a rotating equipment increases to 200,000 to 800,000 rpm, the centrifugal force applied to the rotor becomes much larger than before, so there is a risk that the rotor may be destroyed using current materials. This is because it is highly sensitive.

Here, the centrifugal force F is approximated by the following equation when, for example, a disk shown in FIG. 1 and having the following shape is rotated.

Here, γ: density of material, r: outer diameter of disk, r□ inner diameter of disk, W: angular velocity, g: acceleration of gravity, m: Poisson's ratio As is clear from the above equation, the disk has Centrifugal force is applied in proportion to the square of the number of rotations, so if rotating equipment is made to rotate at high speed, it is possible that the rotation speed will exceed 9 f/am, and such severe rotational centrifugal force This is a material that requires a high tensile strength material that can withstand it.

3! P'''2 In addition, since the rotors of rotating equipment and magnetic bearings utilize electromagnetic phenomena, it is important that they have excellent magnetic properties and are custom-made with soft magnetism. A bearing rotor such as a magnetic bearing is required to have a low coercive force.

Here (b) rotor rotation speed of the rotating equipment (NJ and frequency f)
The relationship with is expressed as follows.

f = "" / 12o (1-8) where P: Number of poles of rotating machine S: Slip Therefore, for example, if we consider a case where a two-pole rotating machine rotates at 200,000 to 80,000 rpm, the converted frequency is several KHz to several KHz. 1
0 KHz range, it is advantageous to use a magnetic material with low iron loss in the above frequency range as the material.

In this way, materials used for high-speed rotating equipment, especially rotors, have high tensile strength and high strength mechanically, while magnetically satisfying soft magnetic properties such as low coercive force and low iron loss. There must be. However, in general, such mechanical customization and soft magnetic customization have a contradictory relationship, so
As stated below, it was extremely difficult to cultivate both qualities.

Now, as a method for increasing the mechanical strength of metal materials, the strengthening methods shown in Table 1 below are known as typical methods.

Table 1 The strengthening mechanism of each of the above strengthening methods utilizes increases in lattice strain, refinement of crystal grain size, processing strain, phase transformation, etc. Since this makes it difficult for the domain wall of the enclosure to move, the soft magnetic tfj properties deteriorate as the strength increases to zero.

Purpose of the Invention This invention provides a material that not only exhibits high tensile strength but also has excellent soft magnetic properties such as low high-frequency iron loss and low coercive force, specifically, a material with a tensile strength of 50 "9/lo" or more and Magnetic flux density B, o: 1.5 T or more, iron loss w1o/1゜oo
The purpose of the present invention is to propose a method for producing a high tensile strength non-oriented electrical steel sheet that satisfies the following: 100 W/- or less.

Introduction to the Invention This invention was developed as a result of reconsidering the various strengthening methods shown in Table 1 above. Based on new knowledge.

In FIG. 2 and FIG. 8, W, Mo, Ti, In, Ni,
Each steel slab having a composition containing up to 5% of AJ and co '1 was heated to 1200"0, hot rolled and rolled into a 2-inch thick hot rolled plate,
After that, it was subjected to normalizing annealing at 900℃ to make the structure uniform, and then cold rolled to a final thickness of 0.15.
Iron loss of each non-oriented electrical steel sheet obtained by cold-rolling the sheet and then annealing it at 950°C for 110 minutes.
The results of examinations regarding 1ooo and tensile strength are shown, respectively. The iron loss was measured using the 4-piece Epstein method, and the tensile strength was measured using a JIS No. 1 test piece using an Instron.

As is clear from Fig. 2.8, as the amount of each solid solution strengthening element added increases, the tensile strength improves, but the iron loss characteristics deteriorate.

However, during the above manufacturing process, instead of cold rolling, 150℃
When repeated warm rolling at a temperature of

This invention is derived from the above-mentioned knowledge.

Structure of the Invention This invention contains Si: 8.5 to 7.0% by weight (hereinafter referred to as "..."), Ti: 0.05 to 8.0%, W: 0.05 to
3.0%.

No: 0.05-8.0%, In: 0.
1-11.5%.

Ni: 0.1~20.0%, Co: 0.5~
20.0% and Al: A silicon steel material slab containing one or more selected from 0.5 to 18.0% within a range not exceeding 20.0% is heated by hot rolling. The patent states that after the sheet is rolled, it is subjected to warm rolling at a temperature range of 300 to 600°C to obtain a final sheet thickness of 0.1 to 0.85 mm, and then final annealed at a temperature range of 850 to 1250°C. This is a method for manufacturing a high tensile strength non-oriented electrical steel sheet.

This invention will be explained in detail below.

First, the reason for limiting the component composition range as described above will be described.

si: 8.5 to 7.0% If the Si amount is less than 8.5%, γ→α phase transformation occurs, which significantly impairs electromagnetic properties, that is, electrical resistance decreases and high frequency iron loss deteriorates. ``In terms of mechanical properties, it is better to have high strength 7.--Poor S1 ≠; If it is higher than 7.0, the steel plate will suddenly become brittle, the yield and productivity will deteriorate, and the saturation magnetic flux density will decrease. also decreases.

Therefore, the Si content was limited to a range of 8.5 to 7.0%.

Ti, W, MO, In, Ni, Go and AJ are equivalent as solid solution strengthening components.

T1 20.05-3.0% If the Tl amount is less than 0.05%, the effect of improving tensile strength will be poor, while if it exceeds 8.0%, the magnetic customization will deteriorate, so it should be 0.05-8. OW returned to 0% range:
0.05~8.0% W amount is ・0.05%, l:,! l) If it is less than 3.0%, the effect of reducing the tensile strength is weak, while if it is more than 3.0%, the magnetic customization will deteriorate significantly, so O No. is limited to the range of 0.05 to 8.0%: 0.05 to 8. If the 0% No sleeve content is less than 0.05%, the improvement in tensile strength cannot be underestimated, while if it exceeds 3.0%, the magnetic customization will deteriorate, so it is limited to a range of 0.05 to 3.0%. did.

Mn: 0.1 to 11.5% - If the In amount is less than 0.1%, the tensile strength improvement effect will be poor, while if it is more than 11.5%, α → γ
It is limited to a range of 0.1 to 11.5% because transformation occurs and the volume fraction of the non-magnetic r phase increases, significantly deteriorating the magnetic customization, and at the same time decreasing brittleness, yield, and productivity.

Ni: 0.1-20.0% If the amount of Nl is less than 0.1%, the tensile strength improvement effect will be poor.
On the other hand, if it exceeds 20%, α→γ phase transformation occurs, the nonmagnetic γ phase increases, and the magnetic customization deteriorates, so the content was limited to a range of 0.1 to 20.0%.

Co: 0.5-20.0% If the Co amount is less than 0.6%, the tensile strength improvement effect cannot be recognized at all, while if it exceeds 20.0%, it is uneconomical and at the same time exhibits hard magnetism. Therefore, 0.5 to 20.
It was limited to a range of 0%.

Ajt': 0.5 to 18.0% If the An content is less than 0.5%, no tensile strength improvement effect can be expected, whereas if it exceeds 18%, the product becomes brittle and is limited to the following.

The above-mentioned solid solution strengthening elements can be added either singly or in combination, but in the case of combined addition, if the amount added exceeds 20.0%, the saturation magnetic flux density will decrease and the magnetic properties will deteriorate. Since it deteriorates, it is important to add it within a range of 20.0% or less.

Now, the molten steel whose composition has been adjusted to the above-mentioned appropriate range is made into a steel slab by an ingot-blowing method or a continuous casting method, and then hot-rolled. In this hot rolling, the hot rolling temperature is so
If the temperature is less than 0°C, cracks will easily occur.On the other hand, if the temperature is 1850'O
The hot rolling temperature is preferably in the range of 800 to 1,850 mm, because if it exceeds 100 mm, the slab surface may melt and it is also uneconomical. Annealing is performed, but the annealing temperature is 75
Below 0°C, it takes a long time to homogenize;
If the annealing temperature exceeds 7, the annealing time can be shortened, but there is a greater risk that the crystal grain size will become unevenly coarsened.
It is preferably in the range of 50 to 1100'O.

The obtained hot rolled sheet is then subjected to warm rolling.
At this time, if the rolling temperature is less than 100°C, the iron loss improvement effect will be poor, and if it exceeds 600"0, it will become uneconomical, so the warm rolling temperature should be in the range of 100 to 600°C.

Such warm rolling effectively improves the core loss of the product in the high frequency range, and the reason is considered to be as follows.

In other words, in normal cold rolling, the dislocation density increases as the reduction rate increases, so the texture exhibits the final stable orientation of cold rolling, and the grain size after final annealing is magnetic%.
However, in the case of warm rolling, the accumulation of dislocations due to rolling is sparser than that of cold rolling, so the texture does not become sharp and there is no dislocation in the rolling direction. It is easy to obtain crystal grains with good directionality and large crystal grains.

By this warm rolling, the hot rolled sheet has a final thickness of 0.1
This is because even if the thickness is made thinner than silk, the effect of improving magnetic customization is small, while if it is thicker than 0.85 mm, the deterioration of the high frequency iron loss percentage increases.

After that, finish annealing is performed at a temperature range of 850 to 1250"0.The reason why the annealing temperature is set to the above range is
Below ℃, it takes a long time to obtain the desired magnetism.
This is because if the temperature exceeds 260°C, there is not only a large possibility that the surface of the steel plate will melt, but also it is uneconomical.

Examples Example 1 Each steel slab having the composition shown in Table 1 below was
After heating to C and hot rolling to obtain a hot rolled sheet with a thickness of 1.0 mm, normalizing annealing was performed at 900°0. Then, after repeatedly performing warm rolling at a temperature of 400°C to a final thickness of 0.1 mm, this plate was rolled at 90 mm.
Final annealing was performed at a temperature of 0°C.

Tensile strength and iron loss Wl of each non-oriented electrical steel sheet obtained
The results obtained for o/1nnn and magnetic flux density 1fB- are also listed in Table 1. For comparison, a similar investigation was also carried out on steel sheets obtained by cold rolling according to the conventional method.
The results are also shown in Table 1.

- As is clear from the results shown in Table 1, the non-oriented electrical steel sheet obtained according to the present invention has -
Tensile strength has been significantly improved without any significant deterioration in magnetic properties.

Example 2 Each steel slab having the composition shown in Table 2 below was prepared using 1260
After heating to C, hot rolling was performed to obtain a hot rolled sheet with a thickness of 1.5 mm.Next, normalizing annealing was performed at 900°C, and warm pressure #; was fully repeated at a temperature of 150°C. The final plate thickness was 0.15 mm.
Tensile strength of each non-oriented electrical steel sheet obtained by final annealing at 80°C for 2 minutes.

Examine iron loss W10/ and magnetic flux density B5o00
The results are also listed in Table 2.

Effects of the Invention As described above, according to the present invention, the tensile strength of a non-oriented electrical steel sheet can be significantly improved without significantly deteriorating its magnetic properties q't.

[Brief explanation of drawings]

Figure 1 is a plan view of a disk with an inner diameter of r and an outer diameter of r2, Figure 2 is a graph showing the influence of various solid solution strengthening elements on iron loss WIQ/1000, and Figure 3 is Similarly, FIG. 4 is a graph showing the influence of various solid solution strengthening elements on tensile strength, and shows the amount of each strengthening element added and the iron loss W 10/1° of a non-oriented electrical steel sheet obtained according to the present invention. It is a graph showing the relationship with 0. Figure 3

Claims (1)

[Claims] L si: 8.5 to 7.0 weight 1 inch, Ti-: 0.05 to 8.0 weight%, W: 0.05 to 8.0 weight%, No. : 0.05-8.0Ti%, Mn: 0.1-11.5% by weight, Ni: 0.1-20.0% by weight, 00: 0.5-20.0% by weight and AJ: 0
．． 20.0% by weight of one or more selected from 5 to 18.0% by weight
After hot-rolling a silicon steel cable slab containing silicon steel cable in a range not exceeding 100 to 600
A final plate thickness of 0.1 to 0.85111 is obtained by repeatedly performing warm rolling in the temperature range of ℃, and then 850℃.
Production method.