JP2000001724A - Bright finish-annealing method of iron-chromium- aluminum alloy sheet, bright finish-annealing equipment and method for evaluating oxidation resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the uniform and good color tone and oxidation resistance on the surface of an Fe-Cr-Al alloy sheet as a product by constituting atmospheric gas in a finish-annealing furnace of thin Fe-Cr-Al alloy sheet of H2 and N2 and controlling the H2 concn. in the atmospheric gas based on the whiteness on the material surface after finish-annealing. SOLUTION: Cold-rollings and annealings are repeated several times, and a coiled material rolled with finish-rolling is recoiled, and after annealing this material 4 in the bright finish-annealing furnace 1, this material is again coiled to obtain the product coil of the Fe-Cr-Al alloy sheet. The atmospheric gas composed of the H2 gas and the N2 gas is supplied into the finish-annealing furnace 1 with an atmospheric gas supplying device 5. When the whiteness based on the signal from a whiteness meter 9 becomes lower than a prescribed value, an atmospheric gas concn. adjusting device 8 decides so that the H2 concn. becomes high in the reverse proportion with the detected value of the whiteness, and signals for controlling opening degrees of the flow rate adjusting valves 6, 7 for H2 gas and N2 gas, are changed so that the H2 concn. becomes the decided value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to thin Fe--Cr
-Bright finish annealing method and equipment for manufacturing an Al alloy plate, and further, Fe-
It relates to a method for evaluating the oxidation resistance of a Cr-Al alloy plate, and is particularly suitable for an ultra-thin Fe-Cr-Al alloy plate as a material for a catalytic converter carrier requiring excellent oxidation resistance under a high temperature environment. The present invention relates to a bright finish annealing method and a method for evaluating the oxidation resistance of equipment and products.

[0002]

2. Description of the Related Art Fe--Cr--Al alloys, in particular, 20Cr
Cr: 19-21% by weight, commonly called -5Al, Al:
Since the iron-based alloy containing 5.5 to 6% by weight has excellent oxidation resistance in a high-temperature environment, it is used as a material for a catalytic converter carrier (catalytic converter carrier) that removes harmful substances in automobile exhaust gas. Widely adopted as. This catalytic converter carrier is extremely thin (30-
Honeycomb with a large number of partition walls (approximately 100 μm)
It is a structural product (honeycomb material) formed in a shape, and the thickness of the Fe—Cr—Al alloy plate as the material is 0.0
It is necessary to manufacture an extremely thin plate of about 3 to 0.1 mm.

In the production of such an ultra-thin Fe—Cr—Al alloy sheet, cold rolling and annealing are performed a plurality of times on a hot-rolled material (hot-rolled sheet) in view of work hardening by cold rolling. By repeating, the thickness is reduced step by step, the final thickness is rolled to the target thickness in finish rolling, and the final adjustment as a product is performed by finish annealing.

In a conventional production line process, for example, when a hot-rolled thin plate having a thickness of 2 mm is hot-rolled into an extremely thin product having a thickness of 0.05 mm, the thickness of the sheet is reduced to 0. After the first annealing, pickling, surface grinding, etc. were performed sequentially, the second rolling (intermediate rolling) was performed to make the sheet thickness 0.1 mm (intermediate thickness), and the second annealing (intermediate annealing) was performed. )
After that, the third rolling (finish rolling) results in a thickness of 0.05 mm.
And then finish annealing is performed.

Here, the first annealing is performed in an air atmosphere, and surface oxides generated by the annealing are removed by pickling and grinding in the next step. However, the intermediate annealing and the finish annealing are not performed. This is performed by bright annealing (commonly known as BA) performed in a non-oxidizing atmosphere. This is because if the pickling is performed after intermediate annealing or finish annealing, the length of the plate is much longer than at the time of the first annealing, so long equipment is required. This is because the smoothest surface is dulled by pickling or grinding.

[0006] Here, the atmosphere gas of BA is obtained by intermediate annealing.
Is AX gas (H_Two: 75 vol.%, N _Two: 25vol.%),
Nitrogen gas (N_Two: 100 vol.%)
used.

[0007] The manufactured Fe-Cr-Al alloy plate is required to have high oxidation resistance because it is used in a high temperature environment when used as a material for the above-mentioned catalyst. For this reason, the oxidation resistance of conventionally manufactured products is evaluated.

In the evaluation method, a part of a product coil is cut out as a sample, and the sample is subjected to 1100 ° C.
The sample was allowed to stand for 240 hours or more in the above high temperature environment, and then the amount of increase in oxidation was determined from the weight of the sample and evaluated.

[0009]

SUMMARY OF THE INVENTION In order to increase the productivity of ultra-thin Fe-Cr-Al alloy sheets in response to an increase in demand for honeycomb materials, the present inventors have increased the processing speed in intermediate annealing. Is considered, and the thickness of the intermediate annealing plate is set to, for example, 0.1%.
By changing the thickness from 0.3 mm to 0.3 mm, the processing speed of intermediate annealing is raised to a thickness that allows stable passing, that is, the thickness and the processing speed are increased, and the throughput in intermediate annealing is greatly improved. Then, the rolling reduction in the finish rolling was increased to produce the desired finished thickness.

However, when a test production was actually performed, although the productivity was improved, the material surface after the finish annealing tended to be darker (blackening material) than in the past. Such a blackening material leads to impairing the appearance of the honeycomb material.

Further, as a result of further investigation on the blackening material, it was found that the oxidation resistance was also deteriorated. Further, in the evaluation of the oxidation resistance of the product after the finish annealing, the test cost is high and it takes a long time before the evaluation result is obtained. In addition, since it becomes difficult to perform an oxidation resistance test on all product coils, it is easy to perform a sampling test on some product coils with the same charge, and even with the same coil, only the tip is evaluated. I will.

The present invention has been made in view of the above-mentioned circumstances, and has a brilliant finish capable of achieving uniformity while improving the surface color and oxidation resistance of an Fe—Cr—Al alloy plate as a product. An object of the present invention is to provide an annealing method and equipment, and to provide a simple method for evaluating oxidation resistance of a manufactured Fe—Cr—Al alloy sheet.

[0013]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is directed to a thin Fe-Cr-Al alloy obtained by repeating cold rolling and annealing a plurality of times. In the bright finish annealing method for manufacturing a plate, the atmosphere gas of the finish annealing furnace is composed of H ₂ , N ₂ and unavoidable impurities, and the atmosphere gas in the atmosphere gas is based on the whiteness of the material surface after the finish annealing. and it provides a bright finish annealing method Fe-Cr-Al alloy plate, characterized by controlling the concentration of H _2.

Here, controlling the H ₂ concentration is based on N ₂
It is the same as controlling the density. Next, the invention according to claim 2 provides a bright finish annealing method for producing a thin Fe-Cr-Al alloy plate by repeating cold rolling and annealing a plurality of times, wherein the atmosphere gas of the finish annealing furnace is used. To H ₂ , N
_2, and with constituting unavoidable impurities, to provide a bright finish annealing method Fe-Cr-Al alloy plate, characterized by controlling the concentration of H ₂ in the atmospheric gas on the basis of the reduction rate at finish rolling Things.

Here, controlling the H ₂ concentration is based on N ₂
It is the same as controlling the density. Next, the invention described in claim 3 is a bright finish annealing facility for producing a thin Fe-Cr-Al alloy plate by repeating cold rolling and annealing a plurality of times, and the outlet side of a finish annealing furnace. Characterized in that a whiteness meter for detecting the whiteness of the material surface is disposed
An object of the present invention is to provide bright finish annealing equipment for a Cr-Al alloy plate.

Next, the invention described in claim 4 is different from the invention described in claim 3 in that at least H ₂ gas and N
Atmosphere gas supply device for supplying ₂ gases as the atmosphere gas into the finishing annealing furnace, and at least one of the H ₂ gas and N ₂ gas based on the detection value of the whiteness meter through the atmosphere gas supply device. Atmosphere gas concentration adjusting means for adjusting the supply amount.

Next, a fifth aspect of the present invention is to provide a thin Fe-Cr-Al alloy by repeating cold rolling and annealing a plurality of times.
In a bright finish annealing facility for producing an alloy sheet, an atmosphere gas supply device for supplying at least H ₂ gas and N ₂ gas as atmosphere gases into the finish annealing furnace, and finish rolling through the atmosphere gas supply device. Atmosphere gas concentration adjusting means for adjusting at least one gas supply amount of the H ₂ gas and the N ₂ gas based on the rolling reduction in the Fe-Cr-Al alloy plate bright finish annealing equipment. To provide.

Next, according to the present invention, a thin Fe—Fe— produced by repeating cold rolling and annealing several times.
A method for evaluating the oxidation resistance of a Fe-Cr-Al alloy sheet, comprising measuring the whiteness of the material after finish annealing for the Cr-Al alloy sheet, and evaluating the oxidation resistance based on the measured whiteness. Is provided.

In order to clarify the cause of blackening of the product after the finish annealing, the present inventors applied GDS (Glow Discharge Spect) to the surface of the blackening material.
(Roscopy), a large amount of AlN was detected. That is, it was found that nitriding occurred in the blackening material, and that the degree of nitriding increased as the blackening progressed.

Therefore, as described above, since the rolling reduction in the finish rolling is increased, it is estimated that the increase in the rolling reduction caused the blackening, and then the reduction in the finishing rolling was reduced. The relationship between the whiteness of the product surface after finish annealing was investigated. The result is shown in FIG.

Here, the whiteness is defined as Hunter whiteness:
It shows the color tone of the plate surface based on w (Lab), and irradiates the sample with white light, and the tristimulus values of the reflected light (three independent quantities for determining the color, and the spectrum of unit energy) A color solid (black and white lightness is taken on the vertical axis, and hue and saturation are taken on the horizontal axis) to calculate the color in three-dimensional coordinates. (Indicated by the position), the color position of the sample was determined, and the distance between the position and the whiteness was subtracted from 100 and expressed as a value. A whiteness of 100 is pure white and a whiteness of 0 is pure black.

As can be seen from FIG. 1, when the rolling reduction in finish rolling exceeds 60%, the whiteness of the material after finish annealing tends to decrease in proportion to the increase in the rolling reduction. . Considering this tendency in connection with the nitriding tendency, the intermediate thickness is reduced from 0.1 mm to 0.1 mm in order to increase the productivity.
By increasing the thickness to 3 mm, the rolling reduction of finish rolling increases, thereby increasing the strain energy of the surface of the finished rolled material and activating the surface, and nitriding from the surface occurs in the finish annealing performed in a nitrogen gas atmosphere. It is presumed that it became easier.

Next, the oxidation resistance of this blackening material was investigated. FIG. 2 shows the result. Oxidation resistance is 11
Evaluation was made based on the increase in oxidation when left at a high temperature of 50 ° C for 264 hours.

As can be seen from FIG. 2, as the value of whiteness decreases (blackening progresses), the oxidation increase increases, and within a predetermined range, the decrease in whiteness and the increase in oxidation increase are almost equal. It was found that there was a proportional correlation. That is, it was found that whiteness and oxidation resistance had a proportional correlation.

As described above, the blackening of the Fe—Cr—Al alloy annealed after being rolled at a high rolling reduction is due to nitridation during annealing, and the blackening (whiteness) depends on the rolling reduction in finish rolling. The result that there is a correlation was obtained.

Therefore, the atmosphere gas used for the finish annealing is H
If the N ₂ concentration is reduced by adding _two gases,
It can be expected that the blackening can be reduced, and that the blackening can be prevented by reducing the N ₂ concentration (increase the H ₂ concentration) in proportion to the rolling reduction in finish rolling.

Based on the above findings, the above-described inventions have been made. That is, the decrease in the whiteness of the material surface after the finish annealing is proportional to the increase in the rolling reduction of the finish rolling, or the increase in the oxidation increase of the material surface after the finish annealing, and the material surface after the finish annealing. In view of the fact that there is an inverse relationship between the decrease in whiteness of H _{2 and the} concentration of H _{2 in} the atmosphere gas of the finish annealing furnace, the inventions described in claims 1 and 4 require the finish of the surface of the material after finish annealing. The surface color tone and oxidation resistance of the Fe—Cr—Al alloy plate after the finish annealing are made equal to or more than a predetermined value by feedback controlling the H ₂ concentration in the atmosphere gas for the finish annealing based on the whiteness.

Further, the invention according to claim 2 and claim 5 is to feed-forward control the H ₂ concentration in the atmosphere gas of the finish annealing based on the rolling reduction of the finish rolling, so that the Fe—Cr -To make the surface tone and oxidation resistance of the Al alloy plate uniform at predetermined values or more.

Further, the invention of claim 3 provides equipment which enables the bright finish annealing method of the above-mentioned claim 1 or the oxidation resistance evaluation method of the above-mentioned claim 6. Further, the invention described in claim 6 is based on the finding that there is a correlation between the surface tone of the material after the finish annealing and the oxidation resistance based on the above findings, and based on the whiteness of the material after the finish annealing, the acid resistance. By evaluating the feasibility, the evaluation can be performed simply and in a short time, and continuously over the entire length of the coil.

[0030]

Next, a first embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a finish annealing step in the present embodiment, in which the coil rolled by the finish rolling, which is the preceding step, is unwound, and the material 4 is used for the bright finish annealing furnace 1.
And then wound again to produce a product coil of an Fe-Cr-Al alloy plate. In FIG. 3, reference numeral 2 denotes a payoff reel, and reference numeral 3 denotes a tension reel.

The finish annealing furnace 1 is provided with an atmosphere gas.
N by feeding device 5_TwoGas and H _TwoAtmosphere made of gas
Gas gas is supplied. In FIG.
Is H _TwoH to adjust gas flow_TwoGas flow control valve
And code 7 is N_TwoN to adjust gas flow_TwoGas flow rate
Control valve, both flow control valves 6 and 7 are also atmosphere gas concentration
The opening is adjusted by the signal from the adjusting device 8 to finish
H in the atmosphere gas supplied to the blunt furnace 1_TwoThe concentration is adjusted
It has become so.

Here, the flow rate control valves 6 and 7 constitute a part of the atmosphere gas supply device 5 and together with the atmosphere gas concentration adjustment device 8 constitute atmosphere gas concentration adjustment means. Further, in the present embodiment, a whiteness meter 9 is arranged on the exit side of the finish annealing furnace 1, continuously detects the whiteness of the surface of the material 4 after the finish annealing, and outputs the detection signal to the atmosphere gas concentration adjusting device 8. Can be supplied.

The atmosphere gas concentration adjusting device 8 includes a whiteness meter 9.
Based on a signal from the whiteness is less than a predetermined value, as in inverse proportion to the detected value of the whiteness was determined as concentration of H ₂ is increased, the its concentration of H ₂ values, for example, N ₂
The opening signals to the gas flow control valves 6 and 7 are changed to change the atmospheric gas to a target H ₂ concentration.

For example, based on FIG.
When it becomes smaller, the proportional control is performed so that the concentration of the H ₂ gas becomes higher than the initial value so that the value becomes proportional to the decrease in the whiteness.

The initial value of the H ₂ gas concentration is, for example, 10
Set a low value such as VOL.%. Alternatively, the initial value of the H ₂ gas concentration may be set to 0% by setting a high whiteness value for determination of control start.

Of course, the H ₂ concentration in the atmospheric gas may be set higher from the beginning. Further, the adjustment of the H ₂ concentration may be changed continuously or stepwise according to the whiteness. The same applies to other controls described later.

When the brightness of the surface of the material 4 after the finish annealing decreases to a predetermined value or more based on the brightness of the surface of the material 4 by the above-described equipment, the H ₂ concentration is proportionally controlled by feedback, and the brightness decreases. The supply amount of N ₂ is suppressed so that the H ₂ concentration value increases in proportion to.

Thus, even if the contents of the process above the finish annealing are changed in order to improve the productivity, the product after the finish annealing, that is, the Fe—Cr—Al alloy plate having a good surface tone can be obtained. In addition, since the surface color is adjusted to be uniform and the surface color tone is adjusted to be good and uniform, the oxidation resistance can be made uniform within a desired range.

Next, a second embodiment will be described with reference to the drawings. Note that the same reference numerals are given to the same devices and the like as in the first embodiment, and description thereof will be omitted. The basic configuration of the second embodiment is the same as that of the first embodiment as shown in FIG.
When the history information 10 of the rolling reduction of the target coil is input from the finishing rolling equipment in the previous process, and based on the history information 10 of the rolling reduction, if the rolling reduction is equal to or more than a predetermined value, the reduction proportional to the rolling reduction Then, the H ₂ concentration is determined to be high, and the opening signal to the N ₂ gas flow control valve 7 is changed to the desired H ₂ concentration so that the H ₂ concentration value is obtained, for example.

For example, based on FIG. 1, when the rolling reduction becomes 60% or more, the H ₂ concentration is adjusted, and proportional control is performed so that the H ₂ concentration increases in proportion to the increase in the rolling reduction. When the reduction ratio is equal to or more than a predetermined value based on the reduction ratio of the target material 4 before the finish annealing, the proportional control is performed by feed forward, and the H ₂ concentration value is proportional to the reduction ratio. The supply amount of N ₂ is suppressed so as to be higher.

Thus, the product after the finish annealing is obtained.
The surface tone of the Fe—Cr—Al alloy plate is adjusted in a favorable state and uniformly, and furthermore, the surface tone is adjusted in a favorable and uniform manner, so that the oxidation resistance can be uniformized in a desired range.

In addition, in combination with the first embodiment, the atmosphere gas concentration adjusting device 8 determines the H level in the atmosphere gas based on both the whiteness after the finish annealing and the reduction ratio in the previous step.
_{2 The} density may be adjusted.

Next, a third embodiment will be described with reference to the drawings. Note that the same reference numerals are given to the same devices and the like as in the first embodiment, and description thereof will be omitted. In the present embodiment, the oxidation resistance of a Fe—Cr—Al alloy plate as a product is evaluated.

The configuration of this embodiment is as shown in FIG.
Similar to the first embodiment, a whiteness meter 9 is arranged on the exit side of the finish annealing furnace 1, and the whiteness meter 9 is used to transfer the material 4 to be conveyed.
The whiteness of the surface is detected, and the detection signal is supplied to the evaluation device 11.

The evaluation device 11 determines that the case where the whiteness is lower than a predetermined value is the oxidation resistance failure, based on the relationship between the increase in oxidation and the whiteness obtained in advance through experiments and the like. For example, if the oxidation resistance is 0.8 mg / cm ² or less and the oxidation resistance is in the good range, the whiteness of 46 or more is determined to be acceptable from FIG.

In the above-described structure, the oxidation resistance of the product coil is easily evaluated during the transportation from finish annealing to winding on a tension reel, and the evaluation is made over the entire length of the material 4. Done.

In the above embodiment, the evaluation is determined by the evaluation device 11, but the detection value of the whiteness meter 9 may be directly visually checked by an operator. Further, in the above embodiment, the case where the evaluation is performed during the finish annealing step is described as an example.However, an evaluation step is separately provided as a step after the finish annealing step, and the coil wound after the finish annealing is provided. The evaluation may be performed while rewinding the coil, and it is not always necessary to evaluate the entire length of the coil.

[0048]

EXAMPLE ZR was applied to a hot-rolled thin sheet (2 mm thick) of an iron-based alloy containing 20% by weight of Cr and 5.5% by weight of Al.
(Zenjimia mill) cold rolled to a thickness of 0.8m,
After annealing, pickling and surface conditioning, cold rolling (intermediate rolling) to an intermediate thickness of 0.3 mm by ZR, intermediate annealing at 860 ° C, and cold rolling to a finishing thickness of 0.05 mm by ZR (finishing rolling) Then, when the finish rolling reduction was 83.3%, the finish annealing furnace 1 was
The H ₂ concentration was adjusted to 75 vol.%, And finish annealing was performed in the finish annealing furnace 1. When the whiteness of the product after the finish annealing was confirmed, it was 52.0, which was good, and it was confirmed that blackening was prevented.

[0049]

As described above, when the present invention is employed, the processing contents such as finish rolling, which is a step higher than the finish annealing step, for the purpose of improving the productivity of the Fe-Cr-Al alloy sheet, etc. Even if it is changed, the blackening of the material after the finish annealing is prevented only by adjusting the atmosphere gas concentration of the finish annealing to produce a product with good surface tone and oxidation resistance and uniformity. There is an effect that can be.

For example, claim 1, claim 3, or claim 4
According to the invention described in (1), there is an effect that the atmosphere gas concentration for preventing blackening can be adjusted by feedback control only by detecting the whiteness of the material surface after the finish annealing.

According to the second or fifth aspect of the present invention, by using the rolling reduction in the finish rolling before the finish annealing, the atmosphere gas concentration for blackening prevention by feedforward control is reduced. There is an effect that it can be adjusted.

According to the third or sixth aspect of the present invention, the correlation between the whiteness of the material surface after finish annealing and the oxidation resistance (or oxidation increase) discovered by the present inventors has been found. Inexpensive, easy and quick, Fe-Cr as a product
-There is an effect that the oxidation resistance of the Al alloy plate can be determined. Moreover, evaluation can be easily performed over the entire length of the product.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of oxidation increase and whiteness of a 20Cr-5Al iron-based alloy steel finish-annealed material.

FIG. 2 is a diagram showing the relationship between the whiteness of a 20Cr-5Al iron-based alloy steel finish-annealed material and the rolling reduction in finish rolling.

FIG. 3 is a configuration diagram for explaining a finish annealing facility according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram for explaining finish annealing equipment according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram for explaining a finish annealing facility according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 Finish annealing furnace 4 Material 5 Atmospheric gas supply device 8 Atmospheric gas concentration adjusting device 9 Whiteness meter 10 Reduction rate history information 11 Evaluation device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Genichi Ishibashi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Chiba Works, Ltd. (72) Inventor Tsukasa Matsubara 1 Kawasaki-cho, Chuo-ku, Chiba-shi Inside Kawasaki Steel Corporation Chiba Works (72) Inventor Hirohiro Yamaguchi 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside Kawasaki Steel Corporation Chiba Works (72) Inventor Kenichi Fujita 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture F term in Kawasaki Steel Corporation Chiba Works (reference) 2G059 AA02 BB15 MM12 4K043 AA01 AB01 AB12 BB01 BB05 DA05 EA07 FA09 FA12 GA10

Claims (6)

[Claims] In a bright finish annealing method for producing a thin Fe—Cr—Al alloy sheet by repeating cold rolling and annealing a plurality of times, the atmosphere gas of the finish annealing furnace is H ₂ , N ₂ .
_2, and inevitable with consist impurities, H ₂ of the atmospheric gas on the basis of the whiteness of the material surface after final annealing
A bright finish annealing method for a Fe-Cr-Al alloy sheet, characterized by controlling the concentration. 2. A bright finish annealing method for producing a thin Fe—Cr—Al alloy sheet by repeating cold rolling and annealing a plurality of times, wherein the atmosphere gas of the finish annealing furnace is H ₂ , N ₂ .
_2, and with constituting unavoidable impurities, bright finish annealing method Fe-Cr-Al alloy plate, characterized by controlling the concentration of H ₂ in the atmospheric gas on the basis of the reduction ratio at the finish rolling. 3. A bright finish annealing facility for producing a thin Fe—Cr—Al alloy sheet by repeating cold rolling and annealing a plurality of times, wherein the whiteness of the material surface is determined on the exit side of the finish annealing furnace. Fe-characterized by providing a whiteness meter for detection
Bright finish annealing equipment for Cr-Al alloy sheets. 4. An atmosphere gas supply device for supplying at least H ₂ gas and N ₂ gas as atmosphere gases into the finish annealing furnace, and the H gas is supplied via the atmosphere gas supply device based on a detection value of a whiteness meter. according to claim 3, characterized in that it comprises a ambient gas concentration adjusting means ₂ for adjusting the gas and N ₂ at least one of the gas supply amount of the gas Fe-
Bright finish annealing equipment for Cr-Al alloy sheets. 5. A method of thinning by repeating cold rolling and annealing a plurality of times.
Finish sintering in the production of an original Fe-Cr-Al alloy plate
At least H_TwoGas and N _TwoGas atmosphere
Atmosphere gas supplied to the above finishing annealing furnace as ambient gas
The finishing pressure is supplied via the supply device and its atmospheric gas supply device.
H based on the draft in rolling_TwoGas and N_TwoLow on gas
Atmosphere gas concentration adjustment to adjust at least one gas supply
Fe-Cr-Al alloy comprising:
Bright finish annealing equipment for plates. 6. For a thin Fe—Cr—Al alloy plate manufactured by repeating cold rolling and annealing a plurality of times, the whiteness of the material after finish annealing is measured, and acid resistance is determined based on the measured whiteness. Fe-Cr characterized by evaluating the chemical nature
-Method for evaluating oxidation resistance of Al alloy plate.