JPH06306552A - Silicon stainless steel sheet - Google Patents

Abstract

PURPOSE:To produce a silicon steel sheet excellent in soft-magnetic properties, corrosion resistance, atmospheric corrosion resistance, and press formability by combinedly adding specific small amounts of Ti and B to a ferritic stainless steel. CONSTITUTION:A ferritic stainless steel, which has a composition containing, by weight, <0.02% C, 0.01-1.00% Si, 0.01-1.00% Mn, 7.0-15.0% Cr, and <0.02% N or further containing at least one kind among <3.00% Mo, <2.00% Cu, <3.00% Ni, <1.00% Nb, and <1.00% V, is used, and 0.02-0.25% Ti and 0.0002-0.01% B are combinedly incorporated into this steel. A slab of this stainless steel is hot-forged and cold-rolled into a sheet. By this method, the ferritic stainless steel sheet, improved in magnetic properties and corrosion resistance by finely and uniformly dispersing C and N as impurities into a structure by the addition of Ti and B and also improved in press formability by refining crystalline grains, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic stainless steel sheet having not only excellent soft magnetic characteristics and corrosion resistance but also good press formability, and particularly to an electromagnetic relay material, a magnetic shield material and a magnetic yoke material. It is suitable for use.

[0002]

2. Description of the Related Art As an electromagnetic relay material, a magnetic shield material, and a yoke material, conventionally, pure iron-based materials have been subjected to zinc chromate treatment in terms of weather resistance and corrosion resistance, and surface treatments such as nickel and chromium. The applied one has been used, but in recent years, a non-plated one has been directed from the viewpoint of environmental problems and pollution problems.

Therefore, various electromagnetic stainless steels have been developed as materials that do not require surface treatment such as plating. Particularly, such electromagnetic stainless steels include 13-18Cr-1-3Si alloy steels (Patent No. 439,764). No.) is widely used.

[0004]

However, although these electromagnetic stainless steels are excellent in weather resistance and corrosion resistance, they have a low magnetic permeability of 3000 to 4000 or less and are not sufficient as a material for electromagnetic relays. As a shield material and a yoke material, problems remain where breakage and cracks occur during press molding. This invention advantageously solves the above problems, and it goes without saying that it is excellent in weather resistance and corrosion resistance, as well as in soft magnetic characteristics such as magnetic permeability, and further proposes an electromagnetic stainless steel sheet having good press formability. The purpose is to

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the inventors have extensively studied the composition of components of electromagnetic stainless steel. When added,
(1) Effectively acting on C and N in the alloy, magnetic properties and corrosion resistance are greatly improved, (2) Also, the crystal grains become fine and sized, and the coarsening of each crystal grain is suppressed as much as possible. , Susceptibility to breakage and cracking during press forming is greatly reduced,
I got the knowledge. The present invention is based on the above findings.

That is, according to the present invention, C: 0.02 wt% (hereinafter simply referred to as%) or less, Si: 0.01 to 1.00%, Mn: 0.
01-1.00%, Cr: 7.0-15.0%, Ti: 0.02-0.25
%, B: 0.0002 to 0.01%, N: 0.02% or less, and the balance is substantially composed of Fe. Electromagnetic stainless steel sheet (first
Invention).

Further, the present invention is C: 0.02% or less,
Si: 0.01-1.00%, Mn: 0.01-1.00%, Cr: 7.0-
15.0%, Ti: 0.02-0.25%, B: 0.0002-0.01%,
N: Including 0.02% or less, Mo: 3.00% or less, C
u: 2.00% or less, Ni: 3.00% or less, Nb: 1.00% or less, V: 1.00% or less, and at least one selected from the group consisting of an electromagnetic stainless steel sheet having a substantially Fe composition (second Invention).

Below, the experimental results that form the basis of the present invention will be explained. Soft magnetic properties, corrosion resistance, and forming workability when B is added up to 0.02% to a basic composition of 10% Cr steel and 0.15% of Ti contained in this basic steel and not containing Ti. investigated. Each alloy steel was induction-melted in Ar gas by 5 kg each, and then a 65 mmφ ingot was produced. Then, each ingot was hot forged at 1050 ° C. to a thickness of 10 mm, and then cold rolled to a thickness of 1 mm, It was used as a test material. Fig. 1 (a) and (b) show the results of examining the permeability and coercive force of each of the test steels thus obtained after magnetic annealing at 950 ° C, and the results of examining the pitting potential and Erichsen value. 2 (a),
Each is shown in (b).

As is apparent from FIGS. 1 and 2, 10 containing Ti
Cr-0.15Ti steel shows the maximum magnetic permeability and the minimum coercive force when the B content is 0.002 to 0.004%, and the magnetic properties are remarkably improved. Moreover, when the B content is 0.002 to 0.006%, the pitting corrosion potential is Shows a maximum and the corrosion resistance is significantly improved. Further, it has been found that the Erichsen value is high when the B content is in the range of 0.0002 to 0.01%. On the other hand, 10Cr steel containing no Ti, even if B is added,
Both the pitting potential and the Erichsen value were only deteriorated.

As described above, by incorporating Ti and B in combination, not only the magnetic properties but also the corrosion resistance and the formability can be greatly improved. Although the above-mentioned improvement mechanism has not been clarified yet, when trace amounts of Ti and B are simultaneously added to ferritic stainless steel, they effectively act on C and N in steel, and carbon and nitride. Are finely and uniformly dispersed in the grains, and Ti is (Fe, Cr) ₂
It is presumed that this is because the precipitation of B, FeB, etc. is suppressed, and further, B acts effectively on the grain boundaries to improve the magnetic characteristics and corrosion resistance. However, if the addition amount of Ti and B exceeds a certain amount, (Fe, Cr) ₂ B, FeB, etc. are precipitated, and conversely, magnetic properties and corrosion resistance are impaired. When Ti is not included, it depends on the added B (Fe, Cr).
_{Since 2} B, FeB, BN, etc. are precipitated, it is considered that the magnetic properties and corrosion resistance are rather deteriorated.

[0011]

In the present invention, the reason why the composition of the alloy steel is limited to the above range is as follows. C: 0.02% or less C deteriorates magnetic properties and press workability, including corrosion resistance, in stainless steel, so it is desirable to suppress it to 0.01% or less, but it is unavoidably mixed when manufacturing stainless steel. , 0.02% or less considering the actual operation.

Si: 0.01 to 1.00% Si is not only useful as a deoxidizer in steel, but also contributes effectively to the improvement of the magnetic properties of ferritic stainless steel, and also increases the electrical resistance and increases the high frequency. It is also an element useful for improving the response characteristics of the region. However, if the content is
If it is less than 0.01%, its effect of addition is poor, while if it exceeds 1.00%, it causes a marked increase in hardness and impairs press workability, so the content was limited to the range of 0.01 to 1.00%.

Mn: 0.01 to 1.00% Mn is an element effective as a deoxidizing agent in stainless steel, but on the other hand, it impairs magnetic properties, so it is limited to 1.00% or less.

Cr: 7.0-15.0% Cr is a main component in the alloy steel of the present invention, and is one of the most effective elements for corrosion resistance, magnetic properties and electric resistance. In particular, by coexisting with Ti and B, which will be described later, the oxide film after magnetic annealing is made extremely dense and strong, has excellent corrosion resistance, and improves magnetic properties. However, if the content is less than 7.0%, the effect is poor, while
If it exceeds 15.0%, not only the press workability is deteriorated, but also it becomes expensive, so the range was set to 7.0 to 15.0%.

Ti: 0.02 to 0.25% Ti is the most important element in this alloy together with B, and when it coexists with B, it effectively acts on C and N in steel,
By uniformly finely dispersing C and N, it contributes to the improvement of magnetic characteristics and corrosion resistance. Moreover, it is also a useful element that makes the crystal grains before press molding fine and sized to dramatically improve the press moldability. However, the content is 0.02
If the content is less than 0.1%, the effect is not sufficient, while if it exceeds 0.25%, the effect reaches saturation and adversely affects the manufacturing process. Therefore, the content is limited to the range of 0.02 to 0.25%.

B: 0.0002 to 0.01% B is a particularly useful element in the present alloy together with Ti, and acts effectively on C and N in the present alloy to improve not only magnetic properties and corrosion resistance but also Also, it contributes effectively to the improvement of press formability by refining the crystal grains. However, if the content is
If it is less than 0.0002%, its effect is not sufficient, while if it exceeds 0.01%, the workability in hot or cold is impaired, so 0.00
The content is set to be in the range of 02 to 0.01%.

N: 0.02% or less N, like C, is an element in stainless steel that significantly deteriorates corrosion resistance, magnetic properties and press workability, and it is desirable to reduce it as much as possible, but in the range of 0.02% or less. Is acceptable in.

Although the basic components have been described above, in the present invention, in addition to the above, Mo, Cu, Ni, and
At least one selected from Nb and V can be appropriately added within the following range. Mo: 3.00% or less, Cu: 2.00% or less, Ni: 3.00% or less, N
b: 1.00% or less and V: 1.00% or less Mo, Cu, Ni, Nb and V are all useful not only for improving the corrosion resistance of this alloy but also for improving press formability. However, if the amount exceeds the above-mentioned upper limit amount, not only the press moldability is deteriorated but also the cost becomes high.

The electromagnetic stainless steel sheet according to the present invention can be manufactured by the following steps according to a conventional method. That is, after melting in a normal converter or electric furnace, A
After refining with OD, COD, etc., it is made into a steel piece by continuous casting or ingot-casting method, then hot-rolled, annealed / pickled, then cold-rolled and cold-rolled in a predetermined shape. And

[0020]

[Examples] Sample steels having the compositional compositions shown in Table 1 (No. 1 to 1)
Each of 7) is induction melted by 5kg in Ar stream, 65mm
It was a φ ingot. Then each ingot at 1050 ℃
After hot forging to a thickness of 10 mm, it was cold-rolled to a thickness of 1 mm to obtain a test material. Table 2 shows the results of examining the soft magnetic properties, corrosion resistance, and press formability of the test materials thus obtained.

The soft magnetic characteristics are as follows: outer diameter: 45 mm, inner diameter: 30
A ring sample having a thickness of 1 mm and a thickness of 1 mm was prepared, magnetically annealed at 750 to 1050 ° C., and the DC magnetic characteristics were measured with a BH loop tracer. Excellin test, one side: 100 mm, thickness: 1
mm test pieces were prepared and subjected to a test after magnetic annealing. Corrosion resistance is 15mm in diameter and 15mm in length. After making a test piece, sand it up to No. 800 with sandpaper and then in vacuum at 950 ℃ for 2h.
After magnetic annealing, the pitting potential was measured in 3.5% NaCl aqueous solution (30 ℃).

[0022]

[Table 1]

[0023]

[Table 2]

As is clear from Table 2, conventional steels containing no Ti and B, No. 12 (SUS410) and No. 13 (13Cr-2Si).
None of them had good results in terms of press moldability, magnetic properties and corrosion resistance. Comparative Steel No. 14 in which Cr was less than the lower limit had good press formability, but was particularly inferior in corrosion resistance. No.15 steel is C, Ti
Is excessively contained, press formability, magnetic properties,
Both were inferior in corrosion resistance. No.16 steel is Cr, Mo, Cu,
Since Ni was excessively contained, the corrosion resistance was good, but the press formability and magnetic properties were poor. No. 17 steel was inferior in press formability, magnetic properties and corrosion resistance because it contained N and B in excess.

On the other hand, all of Nos. 1 to 11 according to the present invention show a high Erichsen value, and the magnetic characteristics are Hc≤0.
80A / cm, μm ≧ 5000, B ₂₅ ≧ 1.25T were good, and the corrosion resistance was as high as 50 mv or more.

[0026]

As described above, according to the present invention, it is possible to obtain an electromagnetic stainless steel sheet which is excellent not only in soft magnetic characteristics but also in corrosion resistance and press formability. Thus, an electromagnetic relay material, a magnetic shield material, and a yoke material can be obtained. It is a great place to contribute to the industrial world.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between B content and magnetic permeability (a) and coercive force (b).

FIG. 2 is a graph showing the relationship between B content and pitting potential (a) and Erichsen value (b).

Claims (2)

[Claims] 1. C: 0.02 wt% or less, Si: 0.01 to 1.00 wt.
%, Mn: 0.01 to 1.00 wt%, Cr: 7.0 to 15.0 wt%, Ti: 0.02 to 0.25 wt%, B: 0.0002 to 0.01 wt%, N: 0.02 wt% or less, and the balance is substantially Fe. Electromagnetic stainless steel sheet with composition. 2. C: 0.02 wt% or less, Si: 0.01 to 1.00 wt.
%, Mn: 0.01 to 1.00 wt%, Cr: 7.0 to 15.0 wt%, Ti: 0.02 to 0.25 wt%, B: 0.0002 to 0.01 wt%, N: 0.02 wt% or less, and Mo: 3.00 wt% or less , Cu: 2.00 wt% or less, Ni: 3.00 wt% or less, Nb: 1.00 wt% or less, V: 1.00 wt% or less, and the balance is an electromagnetic composition that is substantially Fe. Stainless steel plate.