JPH0633197A - Fe-Cr alloy with excellent workability - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an Fe-Cr alloy excellent in acid resistance and oxidation resistance as well as workability and corrosion resistance. [Structure] 3% by weight ≤ Cr ≤ 60% by weight, C + N + O + P
Fe-Cr alloy with + S ≦ 100 ppm. Further, in addition to the above, 0.01% by weight ≦ Ni + Co + 2Cu ≦ 6% by weight Fe—Cr alloy, and in addition to the above, 0.1%
% By weight ≦ 3Al + 2Si + Mn ≦ 50% by weight and / or 0.001% by weight ≦ 4Ca + 4Mg + REM ≦ 0.
Fe-Cr alloy which is 2% by weight.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is an F alloy which is remarkably excellent in processability.
It relates to an e-Cr alloy. The present invention relates to a Fe—Cr alloy excellent in acid resistance in addition to workability. The present invention also relates to a Fe-Cr alloy having excellent oxidation resistance in addition to workability.
The present invention further relates to a Fe-Cr alloy having excellent acid resistance and oxidation resistance in addition to workability.

[0002]

2. Description of the Related Art Generally, Fe--Cr alloy is known as a material having excellent corrosion resistance, but various improvements such as corrosion resistance and workability of the Fe--Cr alloy have been proposed as shown below. ing.

In Japanese Examined Patent Publication No. 63-58904, an Fe-Cr alloy having a Cr content of 11.0 to 16.0% by weight, particularly a ferritic stainless steel having a Ti content as a specific amount and being excellent in overhanging property and secondary workability Proposing steel.

Japanese Examined Patent Publication No. 64-6264 discloses a Fe-Cr alloy having a Cr content of 8.0 to 35.0% by weight, especially S
It proposes a stainless steel bright annealed material that contains i, Mn and Nb in specific amounts and has excellent rust resistance.

According to Japanese Examined Patent Publication No. 2-1902, an Fe-Cr alloy having a Cr content of more than 20.0% by weight and 25% by weight or less, in particular, Mo, Mn and Nb each containing a specified amount of high temperature resistance during welding. We propose a corrosion-resistant ferritic stainless steel with excellent crackability and weld toughness.

In Japanese Patent Laid-Open No. 61-186451, Cr is used.
Fe-Cr alloy with a content of 25 to 50% by weight, especially S
It proposes an alloy containing i, Mn and Mo in specific amounts and having excellent sour resistance.

In JP-A-62-267450, a high-purity ferritic stainless steel which is a Fe-Cr alloy having a Cr content of 16 to 19% by weight, and in particular containing a specific amount of Mo and having excellent intergranular corrosion resistance. Is proposed.

In Japanese Patent Laid-Open No. 1-287253, Fe-C having a Cr content of 15 to 26% by weight and an Al content of 4 to 6% by weight.
It proposes an Al-containing ferritic stainless steel which is an r-Al alloy and contains a small amount of a rare earth element in a specified amount and is excellent in oxidation resistance and manufacturability.

According to Japanese Patent Laid-Open No. 2-232344, a Fe-Cr alloy having a Cr content of 25.0 to 30.0% by weight, in which a specific amount of Mo is contained, is excellent in biofouling resistance and seawater resistance. Ferritic stainless steel is proposed.

In Japanese Patent Laid-Open No. 3-2355, the Cr content is 1
A ferritic stainless steel having a Fe-Cr alloy content of 6.0 to 25.0% by weight, particularly containing Nb in a specific amount in the ratio of the total amount of C and N and having excellent cold workability, toughness, and corrosion resistance. Proposing steel.

[0011]

In these Fe-Cr alloys, since the corrosion resistance is important first, Cr is used in a relatively large amount. As a result, when ductility is lowered and workability is not always sufficient, and when it is applied to applications requiring molding workability such as automobile exterior materials and exterior building materials, cracks may occur during processing, or processing conditions However, there is a problem that it is difficult to process, and further improvement in processability has been desired.

That is, an object of the present invention is to provide a Fe-Cr alloy having improved workability. The present invention is Fe-Cr which has acid resistance and oxidation resistance in addition to workability.
The purpose is to provide an alloy.

[0013]

As a result of intensive studies to achieve the above object, the present inventor has surprisingly found that the conventional Fe-
The Fe-Cr alloy, which has a very small amount of impurities such as C, N, O, P, and S existing in the Cr alloy, is remarkably excellent in ductility and has completed the present invention.

That is, the present invention is characterized in that the Cr content is 3 to 60% by weight, the total amount of C, N, O, P and S is 100 ppm or less, and the balance is Fe and inevitable impurities. Provided is a novel Fe-Cr alloy excellent in heat resistance.

The present invention has a Cr content of 5 to 60% by weight,
The total amount of C, N, O, P and S is 100 ppm or less, at least one selected from Ni, Co and Cu is contained in an amount satisfying the following formula (1), and the balance is Fe and inevitable impurities. An Fe-Cr alloy excellent in workability and acid resistance is provided. 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1)

In the present invention, the Cr content is 3 to 60% by weight, the total amount of C, N, O, P and S is 100 ppm or less, and one or more selected from Si, Mn and Al are as follows. Amount satisfying formula (2) and / or Ca, Mg
Fe-Cr excellent in workability and oxidation resistance, containing at least one selected from the group consisting of and rare earth elements (REM) in an amount satisfying the following formula (3), and the balance being Fe and inevitable impurities. Provide alloy. 0.1 wt% ≦ 3Al + 2Si + Mn ≦ 50 wt% (2) 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3)

Further, according to the present invention, the Cr content is 5 to 60% by weight, and the total amount of C, N, O, P and S is 100 ppm.
The amount of one or more selected from Ni, Co and Cu is contained in an amount satisfying the following formula (1), and Si and Mn.
And one or more selected from Al and / or Ca, Mg and a rare earth element (R
EM) containing one or more kinds selected from the following formula (3) in an amount satisfying the following formula (3), and the balance being Fe and unavoidable impurities, which is excellent in workability, acid resistance and oxidation resistance.
An e-Cr alloy is provided. 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) 0.1 wt% ≦ 3Al + 2Si + Mn ≦ 50 wt% (2) 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3)

[0018]

The present invention will be described in more detail below. (I) First, the Fe-Cr alloy of the present invention having excellent workability will be described. FIG. 1 shows the effects of C, N, O and P on the change in elongation and the change in proof stress (yield strength) obtained by a tensile test (JIS Z-2241) for a cold rolled annealed sheet of Fe-18% Cr alloy. , Shows the effect of the total amount of S,
It is clear that when the total amount of C, N, O, P and S is 100 ppm or less, the ductility is remarkably excellent.

In FIG. 1, the change in elongation (%) and the change in proof stress (yield strength) (N / mm ² ) are C + N for each alloy component.
The difference in tensile properties from that of + O + S + P = 500 ppm is shown. The basic tensile properties are as follows. Fe-18Cr, C + N + O + S + P = 500ppm elongation 30
%, Yield strength 330 N / mm ² Fe-30Cr, C + N + O + S + P = 500ppm, elongation 25
%, Yield strength 450 N / mm ²

In the Fe--Cr alloy of the present invention, C,
The total amount of N, O, P and S is 100 ppm or less. As described above, at 100 ppm or less, ductility, that is, workability is remarkably excellent. On the other hand, as it exceeds 100 ppm, the ductility decreases and the workability decreases.

Further, in the Fe--Cr alloy of the present invention, C
The r content is 3 to 60% by weight, preferably 5 to 30% by weight. This is because if it is less than 3% by weight, the corrosion resistance is poor, and if it exceeds 60% by weight, sufficient workability cannot be obtained even if C, N, O, P and S are reduced.

That is, the total amount of C, N, O, P and S is 10
F of 0 ppm or less and Cr content of 3 to 60% by weight
The e-Cr alloy has remarkably excellent workability and excellent corrosion resistance.

If necessary, Al, Mo, Nb,
Other elements such as B, Si, Mn, Cu, Ni, Co and Ca can be added.

High-purity electrolytic iron and electrolytic Cr may be used as raw materials in order to produce the Fe--Cr alloy of the present invention having excellent workability. In addition, as for the element added as necessary, a high-purity element is used as the raw material. The main impurity of any of the raw materials is oxygen, and the Fe—Cr alloy of the present invention can be produced by melting and casting under an ultrahigh vacuum higher than 10 ⁻⁷ torr to remove this oxygen.

Further, the component system of the present invention is sufficiently effective even in a hot-rolled annealed plate or a cold-rolled annealed plate, and the surface finish of the cold-rolled annealed plate is BA, 2B, 2D, HL, polishing, etc. It goes without saying that the characteristics are fully utilized.

(II) Next, the Fe-Cr alloy of the present invention which has excellent acid resistance in addition to workability will be described.

FIG. 2 is a graph showing the relationship between the total amount of C, N, P, O and S and the corrosion degree for the Fe-36% Cr-3.2% Co alloy, and the total amount is within 100 ppm. It is clear that the corrosion rate is extremely low.

FIG. 3 shows Fe-Cr-1.6% Ni-1.
FIG. 4 is a graph showing the relationship between the Cr content and the corrosion degree for a 4% Co alloy when the total amount of C, N, O, P and S is 100 ppm or less and when it exceeds 100 ppm. From Figure 3, C + N + O + P + S is 100ppm
It is clear that the following alloys have remarkably low corrosion rates as compared with alloys exceeding 100 ppm, and that the tendency is remarkable when the Cr content is 5% by weight or more.

FIG. 4 shows an Fe-38% Cr alloy (however, C
+ N + O + P + S = 62 ppm), Ni + Co
It is a figure showing the relation between + 2Cu and the degree of corrosion, Ni + Co
It has been clarified that when the value of + 2Cu is 0.01% by weight or more, the corrosion degree decreases.

The components of the alloy composition of the present invention will be described below. Cr: 5 to 60% by weight, preferably 10 to 40% by weight. When the Cr content is within this range, an alloy having excellent acid resistance can be obtained as described above. Excessive Cr content is not preferable because it causes deterioration of workability. Also,
The effect of improving acid resistance is saturated.

C, N, O, P, S: The total amount of these elements is 100 ppm or less, preferably 85 ppm or less. As described above, when it is 100 ppm or less, it is combined with other conditions to exhibit excellent acid resistance and is excellent in workability.

Cu, Ni, Co; all of these elements are important and useful elements that have the effect of improving the acid resistance of the alloy. The alloy of the present invention contains one or more selected from these elements, and the amount thereof is within the range that satisfies the following formula.

0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) Preferably, 0.05 wt% ≦ Ni + Co + 2Cu ≦ 5.0 wt% (1a) The blending amount of Ni, Co, Cu is within the above range. If it is small, the corrosion resistance is poor, and if it is large, the manufacturability of the alloy is poor.

The preferred contents of Ni, Co and Cu are as follows, and the reason is the same as above. Ni: 0.05 to 5.0% by weight Co: 0.05 to 5.0% by weight Cu: 0.05 to 2.5% by weight

The Fe--Cr alloy satisfying the above conditions is
It has excellent workability and remarkably excellent corrosion resistance.

Fe excellent in workability and acid resistance of the present invention
-Cr alloys are used as raw materials for ultra-high purity electrolytic Fe and electrolytic C
r, electrolytic Ni, electrolytic Cu, electrolytic Co, iodide method Ti,
It can be produced by using electrolytic reduction Nb, molten salt electrolysis Zr, reduction V, electrolysis Ta, electrolysis reduction W, high-purity ferroboron, or the like.

The main impurity in any of the contents is oxygen, and in order to remove this oxygen, the Fe-Cr of the present invention is prepared by melting and casting under an ultrahigh vacuum of more than 10 ^-5 torr, preferably more than 10 ^-7 torr. Alloys can be produced.

(III) Further, the Fe-Cr alloy of the present invention which is excellent in workability and oxidation resistance will be described. FIG. 5 shows Fe-24% Cr-0.1% REM (Y: 0.05%,
La: 0.03%, Ce: 0.02%) alloy,
It is a graph showing the relationship between the total amount of C, N, O, P and S and the abnormal oxidation area after the continuous oxidation test.
It is clear that the abnormal oxidation area is extremely small when the total amount of P and S is 100 ppm or less.

FIG. 6 shows the relation between the Fe--Cr--Al alloy.
It is a graph which shows the relationship between Cr content and the oxidation increase after an oxidation test, and the total amount of C, N, O, P, and S is 100 pp.
It has been clarified that when the Cr content is not more than m, the oxidative weight increase is remarkably reduced when the Cr content is 3.0% by weight or more.

FIG. 7 shows (3A) for the Fe-28% Cr alloy in which the total amount of C, N, P, O and S is 51 ppm.
(1 + 2Si + Mn) is a graph showing the influence of the value of (1 + 2Si + Mn) on the abnormal oxidation area after the continuous oxidation test.
It is clear that the value of the abnormal oxidation area decreases when the content is more than weight%.

FIG. 8 shows (4Ca) for the Fe-26% Cr alloy in which the total amount of C, N, O, P and S is 72 ppm.
+ 4Mg + REM) and the oxide film peeling area ratio after repeated heating test.
It is clear that when it is 1% or more, the oxide film peeling area ratio is remarkably reduced.

The components and embodiments of the alloy composition of the present invention will be described below. The Fe-Cr alloy excellent in workability and oxidation resistance of the present invention has the following three aspects, and each of them will be described.

(1) First embodiment of the present invention Cr: 3 to 60% by weight, preferably 10 to 40% by weight. When the Cr content is in this range, it is combined with other conditions to form an alloy having excellent oxidation resistance. Excessive Cr content is not preferable because it causes deterioration of workability and saturates the effect of improving the oxidation resistance.

C, N, O, P, S: The total amount of these elements is 100 ppm or less, preferably 85 ppm or less. By satisfying this condition, abnormal oxidation is suppressed. Then, these conditions are combined with other conditions to form an alloy exhibiting excellent oxidation resistance and, at the same time, an alloy having excellent ductility and good workability.

Si, Mn, Al: The alloy of the present embodiment contains at least one of these elements, and the content satisfies the following formula (2), preferably (2a). 0.1% by weight ≤3Al + 2Si + Mn≤50% by weight (2) Preferably 0.5% by weight≤3Al + 2Si + Mn≤25% by weight (2a) Due to such a range, it is possible to combine with other conditions. hand,
The alloy is remarkably excellent in oxidation resistance. If these elements are contained excessively and the value of 3Al + 2Si + Mn exceeds the range of the formula (2), it becomes difficult to produce an alloy, so that the excessive content of these elements should be avoided.

The preferred contents of each individual element and the reasons therefor will be described below. Si: 0.1 to 10.0% by weight If less than 0.1% by weight, it is effective but not remarkable. 10.
If it exceeds 0% by weight, the decrease in manufacturability becomes noticeable. Mn: 0.1 to 5.0% by weight If less than 0.1% by weight, it is effective but not remarkable. When it exceeds 5% by weight, the productivity is conspicuously deteriorated. Al: 0.1 to 4.0% by weight If less than 0.1% by weight, it is effective but not remarkable. 4.0
When it exceeds the weight%, the decrease in the productivity becomes conspicuous.

The Fe-Cr alloy satisfying the above conditions is excellent in oxidation resistance and workability.
It can be suitably used for pipes and the like used in a high temperature repeated oxidation environment.

(2) Second embodiment of the present invention With respect to the Cr content, the contents of C, N, O, P and S, and the preferable content of Fe, the description of the first embodiment is also applied to the present embodiment. To be done. In the alloy of the second aspect,
It contains one or more selected from Ca, Mg and REM. And the contents of these elements are expressed by the following formula (3),
It preferably satisfies (3a). 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3) Preferably, 0.005 wt% ≦ 4Ca + 4Mg + REM ≦ 0.15 wt% (3a)

By satisfying this condition, in combination with other conditions, an Fe-Cr alloy having excellent oxidation resistance and good workability can be obtained.

These elements remarkably improve the protective property of the oxide film formed on the surface of the alloy of the present embodiment, suppress abnormal oxidation that is apt to occur in the ultrathin material, and improve the adhesion between the oxide film and the base material. Has the function of improving

However, if these elements are excessively contained and the value of (4Ca + 4Mg + REM) exceeds 0.2% by weight, surface defects of the alloy are likely to occur, which is not preferable.

The more preferable contents of each of Ca, Mg and REM and the reasons therefor are as follows. Ca: 0.002 to 0.01% by weight Even if less than 0.002% by weight, there is an effect but it is not remarkable.
If it exceeds 0.01% by weight, the decrease in manufacturability becomes noticeable. Mg: 0.002 to 0.01% by weight If less than 0.002% by weight, the effect is obtained but not remarkable.
If it exceeds 0.01% by weight, the decrease in manufacturability becomes noticeable. REM: 0.005 to 0.1% by weight If less than 0.005% by weight, there is an effect but not remarkable.
If the amount exceeds 0.1% by weight, the effect will be saturated and the cost will increase.

Such an alloy of the second aspect of the present invention is
It can be used for the same purpose as the alloy of the first aspect.

(3) Third Aspect of the Invention An alloy satisfying both the conditions of the alloy of the first aspect of the invention and the conditions of the alloy of the second aspect of the invention detailed above, that is, the Cr content is 3 to 60% by weight, the total amount of C, N, O, P and S is 100 ppm or less, and Si,
At least one selected from Mn and Al is represented by the above formula (2).
An Fe-Cr alloy containing a content satisfying the above formula and also containing one or more kinds selected from Ca, Mg and a rare earth element (REM) in a quantity satisfying the formula (3) has further excellent oxidation resistance and workability. It is an alloy that has, and is preferably used for the above applications.

Fe of the present invention including these three embodiments
In order to produce a —Cr alloy, ultra-high purity electrolytic iron, electrolytic chromium, zone melting method silicon, molten salt electrolytic manganese, molten salt electrolytic aluminum, molten salt electrolytic calcium, electrolytic reduced magnesium, electrolytic reduced rare earth metal are used as raw materials. . The main impurity of any of the raw materials is oxygen, and in order to remove this oxygen, the Fe-Cr of the present invention was obtained by melting and casting under ultra-high vacuum of higher than ^10-5 torr.
Alloys can be produced.

(IV) Finally, the Fe-Cr alloy of the present invention which is excellent in acid resistance and oxidation resistance in addition to workability will be described. This alloy of the present invention has the alloy composition particularly excellent in acid resistance described in (II) and the alloy composition particularly excellent in oxidation resistance described in (III). Therefore, only the aspect will be shown below, and the detailed description is (III).
Since it is as described in (III) and (3), its description is omitted.

Like the invention of (III), this invention has three modes, C + N + O + S + P ≦ 100 ppm, and C
In addition to r: 5 to 60% by weight, only the changed portion will be described below for each embodiment. (1) First Aspect of the Present Invention One or more kinds selected from Ni, Co and Cu are contained in an amount satisfying the following formula (1). 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) Preferably, 0.05 wt% ≦ Ni + Co + 2Cu ≦ 5.0 wt% (1a) One or more selected from Si, Mn and Al It is contained in an amount that satisfies the following formula (2). 0.1 wt% ≦ 3Al + 2Si + Mn ≦ 50 wt% (2) Preferably, 0.5 wt% ≦ 3Al + 2Si + Mn ≦ 25 wt% (2a)

(2) Second Aspect of the Invention One or more kinds selected from Ni, Co and Cu are contained in an amount satisfying the following formula (1). 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) Preferably, 0.05 wt% ≦ Ni + Co + 2Cu ≦ 5.0 wt% (1a) Selected from Ca, Mg and rare earth element (REM). At least one of the above is contained in an amount satisfying the following formula (3). 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3) Preferably, 0.005 wt% ≦ 4Ca + 4Mg + REM ≦ 0.15 wt% (3a)

(3) Third Embodiment of the Present Invention One or more kinds selected from Ni, Co and Cu are contained in an amount satisfying the following formula (1). 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) Preferably, 0.05 wt% ≦ Ni + Co + 2Cu ≦ 5.0 wt% (1a) One or more selected from Si, Mn and Al It is contained in an amount that satisfies the following formula (2). 0.1 wt% ≦ 3Al + 2Si + Mn ≦ 50 wt% (2) Preferably, 0.5 wt% ≦ 3Al + 2Si + Mn ≦ 25 wt% (2a) Ca, Mg and rare earth element (REM) are selected. One or more kinds are contained in an amount satisfying the following formula (3). 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3) Preferably, 0.005 wt% ≦ 4Ca + 4Mg + REM ≦ 0.15 wt% (3a)

Since the manufacturing method of the alloy of the present invention is exactly the same as the above, detailed description will be omitted.

[0061]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Corresponding to Invention Alloys 1 to 13 and Comparative Alloys 1 to 12 Corresponding to Claim 1 An alloy having the chemical composition shown in Table 1 was melt cast in a vacuum melting furnace of 10 kg and hot cast. Rolled to a hot rolled sheet with a thickness of 4 mm, annealed for the purpose of recrystallization, hot rolled after descaling to a cold rolled sheet with a thickness of 0.7 mm, finally recrystallized and annealed. It was annealed sheet.

Using the cold-rolled and annealed sheet thus obtained, an elongation value was measured by a tensile test according to JIS Z-2241, and after 50% cold rolling, a 180 ° adhesion bending test in the C direction was performed. Table 2 shows the state of cracking when the test was performed.

The elongation is flat in the L, X and C directions.
Uniform elongation (El_L+ El_C+2 x El _X) / 4 is shown in Table 2
Posted. The work bendability was evaluated as follows. ○ ……… No cracks △ ……… Small cracks × ………… Large cracks

Further, with respect to the test materials obtained in all the examples, changes in elongation and changes in proof stress (yield strength) were examined. Elongation change (%), yield strength (yield strength) change (N / mm
² ) means that C + N + O + S + P = 5 for each alloy component.
The difference in tensile properties from that of 00 ppm is shown. The basic tensile properties are as follows. Fe-18Cr, C + N + O + S + P = 500ppm elongation 30
%, Yield strength 330 N / mm ² Fe-30Cr, C + N + O + S + P = 500ppm, elongation 25
%, Yield strength 450 N / mm ²

C, which is well known as an impurity,
By setting the total amount of N, O, P, and S to 100 ppm or less, cracks do not occur even in the C-direction contact bending test after 50% cold rolling regardless of the amount of Cr, and excellent workability can be obtained. You can see that On the other hand, when the above amount is more than 100 ppm and 200 ppm or less, constant Cr alloy microcracking occurs (Comparative Alloys 1, 2, 3, 4), and when it exceeds 200 ppm or when high Cr exceeds 100 ppm, large cracking occurs. Occurs (comparative alloys 5, 6, 7, 8, 9), and the workability decreases.

On the other hand, comparing the same amount of Cr, C, N,
It can be seen that the elongation is remarkably improved by setting the total amount of O, P and S to 100 ppm or less.

Fe-11 prepared in the same manner as the alloy plate in Table 1
Weight% Cr-0.003% Si-0.005% Mn-
An alloy plate with 0.007% Al composition and varying the total amount of C, N, O, P, S was emery # 600 polished, and salt spray test using 5% NaCl at 50 ° C. The degree of rusting after (24 hours) is shown in Table 2 (score A:
No rusting at all, B: Slight rusting, C: Small rusting, D:
Large scale).

The total amount of C, N, O, P and S is 100 p
It can be seen that when the content is pm or less, the rust resistance is remarkably improved and no rusting occurs at all.

(Example 2) ... Inventive alloys 14 to 20 and comparative alloys 13 and 14 ... Corresponding to claim 2 The test materials having the component ranges shown in Table 1 were put into a 100 kg high frequency induction heating ultra-high vacuum melting furnace. It was made. These test materials were subjected to forging, cutting and hot rolling, followed by annealing and cold rolling to produce a steel plate having a thickness of 1.0 mm.

Then, from these materials, 1 mm ^t ×
A test piece of 50 mm x 50 mm was prepared and immersed in 5% HCl at 40 ° C for 24 hours. 40% H ₂ SO ₄ at 50 ° C for 24 hours. Immersion test was performed to determine the corrosion rate (g / m ² · hr). It was measured. The results are summarized in Table 2. From the results in Table 2, it is clear that in the component range of the present invention, the corrosion in the acid immersion test is significantly suppressed as compared with the materials in the component ranges of the comparative examples. Also, C,
For a material in which the total amount of N, O, P and S is 100 ppm or less, the effect is remarkable when Co + Ni + 2Cu is 0.01% or more.

From these results, the Fe-Cr system (5≤C
r ≦ 60) alloy, the total content of C, N, O, P and S is 100 ppm or less, and one or more of Ca, Ni and Co is 0.01 wt% ≦ Co + Ni + 2Cu ≦
It is clear that an alloy excellent in acid resistance can be obtained by including it in the range of 6% by weight.

(Example 3-1) ... Inventive alloys 21 to 33,
Corresponding to Comparative Alloys 15 to 18 ... Corresponding to Claim 3 The test materials having the components shown in Table 1 were produced in a 100 kg high frequency induction heating ultra high vacuum melting furnace. After forging, cutting, and hot rolling these test materials, annealing cold rolling was repeated 5
A foil strip with a thickness of 0 μm and a width of 200 mm was produced.

Thereafter, the foil strip test pieces (50 μm ^t × 50 mm × 50 mm) produced from these materials were subjected to the continuous oxidation test and repeated heating test by the following methods. The results are shown in Table 2.

(1) Continuous Oxidation Test After exposing the test piece to 1150 ° C. for 300 hours in the air, the abnormal oxidation area was measured. The evaluation was performed as follows. ◎ Abnormal oxidation area is zero ○ Abnormal oxidation area is within 5% △ Abnormal oxidation area is 5 to 20% × Abnormal oxidation area is 20 to 40% × × Abnormal oxidation area is 40% or more

(2) Repeated heating test 1150 ° C. × 30 minutes heating for each test piece in the air → 30
After cooling for 50 minutes repeatedly, the peeled area of the oxide film of the test piece was measured. The evaluation was performed as follows. ◎ Abnormal oxidation area is zero ○ Abnormal oxidation area is within 10% △ Abnormal oxidation area is 10 to 30% × Abnormal oxidation area is 30 to 50% × × Abnormal oxidation area is 50% or more

In the component range of the present invention, the occurrence of abnormal oxidation was suppressed as compared with the component range of the comparative example, and the oxide film was covered with sound and excellent adhesion. On the other hand, the oxide film of the comparative alloy showed an abnormal morphology with poor adhesion. Also, the total of C, N, O, P and S is 100 pp
For materials of m or less, 3Al + 2Si + Mn is 0.1
%, The effect was remarkable. From these results,
Fe-Cr alloy (3≤Cr≤60) alloy, S, P, O,
N and C are 100 ppm or less in total, and Si and A
0.1% by weight of one or more of l and Mn ≦
It is clear that the addition of 3Al + 2Si + Mn ≦ 50% by weight makes it possible to obtain a Fe—Cr alloy having excellent oxidation resistance.

Further, in addition to the above components, Ca, Mg, RE
One or more types of M 0.001% by weight ≦ 4Ca + 4Mg + RE
It is clear that the addition of M in an amount of 0.2% by weight makes it possible to obtain a Fe-Cr alloy having further excellent oxidation resistance.

(Example 3-2) ... Inventive alloys 34 to 41,
Corresponding to comparative alloys 19 and 20 ... Corresponding to claim 3 Test materials having the component ranges shown in Table 1 were produced using a 100 kg high-frequency induction heating ultra-vacuum smelting furnace, and these test materials were forged, cut, and heat-treated. After performing hot rolling, annealing and cold rolling were repeated to manufacture a foil strip having a plate thickness of 50 μm and a width of 200 μm.

Foil strip test pieces (5
0 μm ^t × 50 mm × 50 mm) at a temperature of 110
A continuous oxidation test and a repeated heating test were performed in the same manner as in Example 3-1, except that the temperature was 0 ° C. The results are summarized in Table 2. The evaluation of each test is as follows.

(1) Continuous oxidation test ○ Abnormal oxidation area 5% or less △ Abnormal oxidation area 5 to 20% × Abnormal oxidation area 20% or more (2) Repeated heating test ○ Abnormal oxidation area 10% or less △ Abnormal oxidation area 10 30% x abnormal oxidation area 30% or more

In the composition range of the alloy of the present invention, abnormal oxidation did not occur in comparison with the materials in the composition range of the comparative alloy, and it was covered with a sound oxide film having good adhesion. On the other hand, the oxide film of the comparative alloy had poor adhesion and exhibited a form of abnormal oxidation.

From these results, the Fe-Cr system (3≤C
r ≦ 60) alloy, S, P, O, N, C total 100
ppm or less, and 0.001 ≦ 4Ca + 4Mg + REM ≦ 0.
It is clear that an alloy excellent in oxidation resistance can be obtained by setting the value to 2.

(Example 4) ... Corresponding to invention alloys 42 to 44 and comparative alloy 21 ... Corresponding to claim 4 Test materials having the components shown in Table 1 were produced using a 100 kg high frequency induction heating ultra vacuum melting furnace. After forging, cutting and hot rolling these test materials, annealing and cold rolling were repeated to obtain a plate thickness of 50 μm and a width of 2 μm.
A foil strip of 00 μm was produced. The obtained test material was subjected to the same 5% HCl, 40 ° C. corrosion degree, 40% H ₂ SO ₄ , 50 ° C. corrosion degree, continuous oxidation test, and repeated heating test as in the above-mentioned Examples, Evaluated in the same way,
The results are shown in Table 2. Those within the scope of the present invention have clearly been shown to exhibit excellent properties.

[0085]

[Table 1]

[0086]

[Table 2]

[0087]

[Table 3]

[0088]

[Table 4]

[0089]

[Table 5]

[0090]

[Table 6]

[0091]

[Table 7]

[0092]

[Table 8]

[0093]

[Table 9]

[0094]

[Table 10]

[0095]

[Table 11]

[0096]

EFFECT OF THE INVENTION Basically, an Fe--Cr alloy having excellent workability is provided, and an alloy having excellent acid resistance and / or oxidation resistance is also provided. This allows F over a wide range of fields.
An e-Cr alloy is used.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the total amount of C, N, P, O and S and tensile properties.

FIG. 2 is a graph showing the relationship between the total amount of C, N, P, O and S and the degree of corrosion.

FIG. 3 is a graph showing the relationship between the amount of Cr and the degree of corrosion.

FIG. 4 is a graph showing the relationship between Ni + Co + 2Cu and the degree of corrosion.

FIG. 5 is a graph showing the relationship between the total amount of C, N, P, O and S and the abnormal oxidation area.

FIG. 6 is a graph showing the relationship between the Cr content and the increase in oxidation.

FIG. 7 is a graph showing the relationship between the value (% by weight) of 3Al + 2Si + Mn and the abnormal oxidation area.

FIG. 8 is a graph showing the relationship between the value of 4Ca + 4Mg + REM (% by weight) and the oxide film peeling area ratio.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location C22C 38/18 38/52 (72) Inventor Fusao Togashi Kawasaki-cho, Chuo-ku, Chiba-shi 1 Address Kawasaki Steel Co., Ltd.Technology Research Division (72) Inventor Yoshihiro Yazawa 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Corporation Technology Research Division (72) Inventor Yasushi Kato Chiba City, Chiba Prefecture 1 Kawasaki-machi, Chuo-ku, Kawasaki Steel Corporation Technical Research Headquarters (72) Inventor Keiichi Yoshioka, 1 Kawasaki-machi, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Corporation Technical Research Headquarters (72) Inventor Satoshi Owada 1st Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Technical Research Division

Claims (4)

[Claims] 1. A Cr content of 3 to 60% by weight, C, N, O, P.
And the total amount of S is 100 ppm or less, and the balance Fe
And an inevitable impurity, which is an Fe-Cr alloy excellent in workability. 2. A Cr content of 5 to 60% by weight, C, N, O,
When the total amount of P and S is 100 ppm or less, Ni,
At least one selected from Co and Cu is represented by the following formula (1)
Fe excellent in workability and acid resistance, characterized in that it is contained in an amount satisfying the above conditions and the balance is Fe and unavoidable impurities.
-Cr alloy. 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) 3. A Cr content of 3 to 60% by weight, C, N, O,
The total amount of P and S is 100 ppm or less, Si,
One or more selected from Mn and Al are represented by the following formula (2)
And / or one or more selected from Ca, Mg and a rare earth element (REM) in an amount satisfying the following formula (3), and the balance Fe and unavoidable impurities. Fe- with excellent oxidation resistance
Cr alloy. 0.1 wt% ≦ 3Al + 2Si + Mn ≦ 50 wt% (2) 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3) 4. A Cr content of 5 to 60% by weight, C, N, O,
When the total amount of P and S is 100 ppm or less, Ni,
At least one selected from Co and Cu is represented by the following formula (1)
An amount satisfying the following formula (2) and / or one or more selected from Ca, Mg and a rare earth element (REM). Contains the amount satisfying (3), with the balance Fe
And an inevitable impurity, which is excellent in workability, acid resistance and oxidation resistance. 0.01 wt% ≦ Ni + Co + 2Cu ≦ 6 wt% (1) 0.1 wt% ≦ 3Al + 2Si + Mn ≦ 50 wt% (2) 0.001 wt% ≦ 4Ca + 4Mg + REM ≦ 0.2 wt% (3)