JPH0711061B2 - Electromagnetic stainless steel for cold forging - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic stainless steel for cold forging, and particularly to improving the magnetic characteristics and electric resistance characteristics of ferritic electromagnetic stainless steel and improving cold forgeability. Electromagnetic stainless steel.

(Background Art) Conventionally, chromium-iron-based stainless steel is well known as a corrosion-resistant material, and as a ferritic stainless steel, 13Cr is mainly used in the field of magnetic materials requiring corrosion resistance.
Widely used as a system and 18Cr system. In particular,
This corrosion-resistant soft magnetic material made of electromagnetic stainless steel is used as a magnetic material for electromagnetic valves, relays, and other corrosive environments, and also as a shielding material to be incorporated into electrical parts, specifically, a shield plate for cassette tape, a shield for power transformers. It is used in large quantities in materials and the like.

By the way, conventionally, in order to improve the properties of this type of stainless steel, various techniques for adjusting the alloy components and compositions have been proposed, and for example, an appropriate amount of silicon or aluminum is used for the purpose of improving its magnetic properties. Contain it,
Further, a small amount of lead, calcium, tellurium, selenium, or the like may be added to impart free-cutting property, and further, in order to stabilize the ferrite phase and improve magnetism, titanium,
Techniques for adding zirconium, niobium, tantalum, etc. have been clarified.

However, as far as the present inventors know, a technique for improving the cold forgeability of such stainless steel while maintaining its effective corrosion resistance is
No proposal has been made yet. In particular, it is desirable to improve the cold forgeability, which is one of the forming processes adopted to manufacture the target product, in order to advantageously manufacture the target product from the stainless steel material. is there. Further, it is desirable to improve the magnetic properties and the electrical resistance properties together with the improvement of the cold forgeability, especially in the application of electromagnetic stainless steel. However, as described above, it is possible to meet such requirements. The reality is that no technology has yet been found.

(Structure of the Invention) Here, the present invention has been made in view of such circumstances, and its characteristic feature is weight.
0.015% or less carbon, 3.0% or less silicon, 0.5% or less manganese, 0.030% or less phosphorus, 0.030% or less sulfur, 4 to 4
14% chromium, 0.2-7.0% aluminum (however, aluminum / silicon ≥ 1.0), 300ppm or less nitrogen, and 100
The composition of the stainless steel was adjusted so that it contained less than ppm of oxygen, and the balance consisted essentially of iron, thereby maintaining effective corrosion resistance and improving magnetic and electrical resistance characteristics. , The cold forgeability could be effectively improved.

It is desirable that the electromagnetic stainless steel for cold forging according to the present invention further contains 1.0% or less by weight of at least one of niobium, titanium, zirconium, and vanadium. ,
Due to the inclusion of these elements, the cold forgeability is remarkably improved.

Further, in the above electromagnetic stainless steel for cold forging according to the present invention, together with the above additional content component (selective component),
Alternatively, by itself, it is desirable to further contain at least one or more of 2.0% by weight or less of copper, 3.0% or less of nickel, and 5.0% or less of molybdenum. Stainless steel can be obtained by containing these selective elements. The corrosion resistance of the material is advantageously improved.

Further, the electromagnetic stainless steel for cold forging according to the present invention,
0.03 to 0.3% by weight of lead, 0.002 to 0.02% of bismuth, 0.002 to 0.02% of calcium, 0.01 to 0.2% of tellurium and 0.03 to 0.3% by weight, in combination with the above-mentioned two additional components or alone. It is desirable to further contain at least one or more of the above selenium, and the inclusion of these selective elements will advantageously improve the machinability of the stainless steel material.

(Specific Description of Configuration) The reasons for limiting the components of the electromagnetic stainless steel for cold forging according to the present invention are as follows.

First, chromium (Cr), which is a main alloying component of the electromagnetic stainless steel for cold forging according to the present invention, is an element effective in imparting corrosion resistance and also effective in increasing electric resistance. However, when a large amount of Cr addition exceeding 14% (weight basis, the same applies below), almost no increase in electrical resistance was observed,
Economic efficiency deteriorates. On the other hand, it is effective that the lower limit of the addition amount of chromium is 4% from the viewpoint of corrosion resistance, and if the amount of chromium is too small, it becomes difficult to exert effective corrosion resistance. Therefore, the addition amount of chromium is selected within the range of 4 to 14%. And, by thus reducing the amount of chromium, the magnetic characteristics, especially the saturation magnetic flux density (B ₃₀ ) can be effectively improved.

Further, aluminum (Al), which is a main alloying component, is an element effective in increasing electric resistance, and moreover, it can improve magnetic characteristics [can decrease coercive force (H _c )], so that it is 0.2% or more. It will be included in proportion. However, addition of a large amount of aluminum exceeding 7% causes deterioration of cold forgeability, so the upper limit is set to 7
It is desirable to set it as%. With such a high aluminum content, the electrical resistance characteristics of stainless steel are effectively improved.

Further, silicon (Si) is an element effective in increasing electric resistance, like the above-mentioned chromium and aluminum, and exhibits the characteristic of increasing the electric resistance as Si% in stainless steel increases. . On the other hand, this silicon is an element effective for improving the magnetic properties, in other words, reducing the coercive force (H _c ). However, addition of a large amount of silicon exceeding 3% causes deterioration of cold forgeability, so the upper limit must be 3.0%.

With respect to the above-mentioned amounts of aluminum and silicon, by setting the content ratio (Al / Si) to 1.0 or more, in other words, by setting the following formula: Al / Si ≧ 1.0, good cold forging is performed. It is possible to secure the sex.

Further, although carbon (C) is inevitably introduced during the production of stainless steel, this carbon deteriorates magnetic properties and toughness, and causes deterioration of cold forgeability. The content must be adjusted up to 0.015%.

Further, phosphorus (P), nitrogen (N) and sulfur (S) cause deterioration of cold forgeability, and both nitrogen and sulfur are also elements that adversely affect magnetic properties.
The upper limit is 0.03% (300 ppm), and the content is adjusted.

Then, by reducing the contents of carbon, nitrogen, and sulfur in the stainless steel in this way, the coercive force of the target stainless steel can be lowered and the magnetic properties thereof can be effectively improved. Of.

Further, manganese (Mn) is an element that is inevitably introduced in the manufacturing process of stainless steel, like the above-mentioned carbon, but its large amount impairs the cold forgeability of stainless steel. Therefore, the upper limit must be 0.5%.

Further, since oxygen (O) forms oxide inclusions and significantly deteriorates the cold forgeability of the stainless steel, its upper limit is set to 0.01% (100 ppm), preferably below 0.005% (100 ppm). It is desirable to adjust it so that it is 50 ppm or less. In particular, such a low oxygen content can reduce the coercive force (H _c ) and improve its magnetic properties, and at the same time, can improve the cold forgeability.

In addition to the above-mentioned elements, niobium (Nb), titanium (Ti), zirconium (Zr) and vanadium (V), which are contained as selective elements, are elements that improve the toughness, and are Remarkably improves cold forgeability. However, the addition of a large amount of these elements deteriorates the magnetic properties and also causes the cold forgeability to be impaired. , Will be included.

In addition, since copper (Cu), nickel (Ni) and molybdenum (Mo), which are other selective elements, can effectively improve the corrosion resistance of stainless steel, 2.0% of Cu is used. 3.0% for Ni in the following ratios
In the following ratio, and in the case of Mo, the content will be 5.0% or less.

Furthermore, lead (P
b), bismuth (Bi), calcium (Ca), tellurium (T
e) and selenium (Se) are machinability improving elements, respectively, and are added to give the desired stainless steel free machinability. Then, these elements are added within a range that does not impair cold forgeability and magnetic properties, and specifically, in Pb, 0.03 to 0.3%, Bi
0.002 to 0.02% for Ca and 0.002 to 0.02 for Ca
%, 0.01-0.2% for Te, 0.03-0.3 for Se
In the range of%, each is added alone or in an appropriate combination.

Incidentally, in the electromagnetic stainless steel for cold forging according to the present invention, the remaining components other than the above-mentioned additional elements are substantially composed of iron (Fe), and there are also unavoidable impurities. Needless to say, this is done.

(Examples) Hereinafter, several examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of the examples. It goes without saying that you do not receive it. The present invention is
In addition to the following embodiments, and other than the above specific description, various changes, modifications, improvements, etc. may be added without departing from the spirit of the present invention. It should be understood.

First, a chromium-iron-based alloy having various alloy components and compositions shown in Table 1 below (the balance consisting of Fe and unavoidable impurities) is melted, and then a predetermined ingot is cast from each molten alloy, After that, hot work according to the usual method,
Various target test materials were prepared.

The electrical resistance (ρ), coercive force (H _c ), machinability, corrosion resistance, cold forgeability, and magnetic properties (magnetic flux density: B ₃₀ ) of the various test materials thus obtained were evaluated. did. The machinability, corrosion resistance and cold forgeability were evaluated according to the test methods shown in Table 2 below and based on the evaluation symbols in Table 2.

The results obtained are shown in Table 3 below.

As is clear from the results of Table 3, all of the test materials Nos. 1 to 10 according to the present invention have a low coercive force (H _c ) and a magnetic flux density (B ₃₀ ). It is understood that it is a stainless steel which is high and has extremely excellent cold forgeability. Further, it is recognized that these test materials have sufficient corrosion resistance and are excellent in machinability and electric resistance characteristics.

On the other hand, the test materials Nos. 11 to 16 which are comparative examples have relatively high coercive force (H _c ), low magnetic flux density (B ₃₀ ), and cold forgeability. It is known that it is not sufficient, and it is understood that it is not sufficient as stainless steel, especially as electromagnetic stainless steel.

(Effects of the Invention) As is clear from the above description, the electromagnetic stainless steel according to the present invention has particularly excellent cold forgeability, and has improved magnetic characteristics and electric resistance characteristics, It also has effective corrosion resistance, and is advantageously used as a cold forging material, particularly as an electromagnetic material for corrosive environments, and there is a great industrial significance of the present invention there. .

Claims (8)

[Claims] 1. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
Electromagnetic stainless steel for cold forging containing nitrogen of m or less and oxygen of 100 ppm or less, and the balance being substantially iron. 2. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
Cold forging containing nitrogen of m or less and oxygen of 100 ppm or less and 1.0% or less of at least one of niobium, titanium, zirconium, and vanadium, and the balance substantially iron. For electromagnetic stainless steel. 3. By weight, 0.015% or less carbon, 3.0% or less silicon, 0.5% or less manganese, 0.030% or less phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
Containing nitrogen of m or less and oxygen of 100 ppm or less, and further 2.0%
Electromagnetic stainless steel for cold forging containing at least one or more of the following copper, 3.0% or less of nickel, and 5.0% or less of molybdenum, and the balance being substantially iron. 4. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
m or less nitrogen, and 100ppm or less oxygen, further each 1.0% or less, at least one or more of niobium, titanium, zirconium, and vanadium, 2.0% or less copper, 3.0% or less nickel, and Electromagnetic stainless steel for cold forging, containing at least one kind of molybdenum of 5.0% or less, and the balance substantially consisting of iron. 5. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
Contains nitrogen of m or less and oxygen of 100 ppm or less, and further 0.03
~ 0.3% lead, 0.002-0.02% bismuth, 0.002-0.02
% Calcium, 0.01-0.2% tellurium and 0.03-0.3%
Electromagnetic stainless steel for cold forging containing at least one or more of the above selenium and the balance substantially consisting of iron. 6. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
m or less nitrogen, and 100ppm or less oxygen, each 1.0% or less, at least one or more of niobium, titanium, zirconium, and vanadium, 0.03 ~ 0.
At least one of 3% lead, 0.002-0.02% bismuth, 0.002-0.02% calcium, 0.01-0.2% tellurium and 0.03-0.3% selenium, and the balance substantially iron. Electromagnetic stainless steel for cold forging. 7. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
Containing nitrogen of m or less and oxygen of 100 ppm or less, and further 2.0%
At least one or more of the following copper, 3.0% or less nickel, and 5.0% or less molybdenum, 0.03 to 0.3% lead, 0.002 to 0.02% bismuth, 0.002 to 0.02% calcium, 0.01 to 0.2% Electromagnetic steel for cold forging containing at least one of tellurium and 0.03-0.3% selenium, and the balance substantially consisting of iron. 8. By weight, 0.015% or less of carbon, 3.0% or less of silicon, 0.5% or less of manganese, 0.030% or less of phosphorus, 0.03.
0% or less of sulfur, 4 to 14% of chromium, 0.2 to 7.0% of aluminum (however, aluminum / silicon ≧ 1.0), 300pp
m or less nitrogen, and 100ppm or less oxygen, further each 1.0% or less, at least one or more of niobium, titanium, zirconium, and vanadium, 2.0% or less copper, 3.0% or less nickel, and At least one of 5.0% or less of molybdenum and 0.03 to 0.3% of lead, 0.002 to 0.02% of bismuth, 0.002 to 0.02% of calcium, 0.01 to 0.2% of tellurium and 0.03 to 0.3% of selenium. The electromagnetic stainless steel for cold forging which contains at least 1 sort (s) or more of these, and consists of iron for the remainder.