JPH03184678A - Production of fe-al alloy sheet - Google Patents

Abstract

PURPOSE:To produce the sheet of an Fe-Al alloy in the state of good quality by superposing an Al sheet on a steel sheet having a specific compsn., rolling down the sheets at a specific reduction by means of rolls, heating the sheets to a specific temp., and thereby alloying the Al and the steel. CONSTITUTION:The Al sheet of the thickness corresponding to the Al to be incorporated into the steel sheet is superposed on at least one surface of the steel sheet. The content of the C of this steel sheet is specified to <=0.02wt.% and the content of >=1 kinds of Ti, Nb or Zr to 0.01 to 0.8wt.%. The superposed materials are passed between the rolls and are subjected to the rolling reduction of >=30% to form the laminated and press welded sheet. The laminated and press welded sheet obtd. in such a manner is subjected to a diffusion treatment under the conditions to alloy the Al layer to the steel without melting the Al layer. The sheet of the Fe-Al alloy is easily and inexpensively produced in this way by using the existing production line.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is characterized by a bottom shape at room temperature, excellent oxidation resistance,
This invention relates to an industrial manufacturing method of Fe-A I alloy thin plate having magnetic properties and corrosion resistance.

[Conventional technology]

Fe-A I alloys are known to have excellent high temperature oxidation resistance and magnetic properties. Especially Fe-12%A
I, Fe-16% Al has very good magnetic properties.

However, conventionally, it has been extremely difficult to industrially produce such Fe-A I alloy thin plates. This is F
This is because if a high concentration of Al is contained in E, the material becomes extremely brittle, making it difficult to manufacture it into a thin plate by a combination of conventional rolling and annealing. Although F e-A I alloy is a material with excellent oxidation resistance and magnetic properties, it is not suitable for industrial use because cold rolling is almost impossible and processing into thin sheets is difficult. The reality is that it has not yet been widely used.

As a means of solving the poor workability of this alloy, a conventional method of performing special warm rolling (for example, J.

F, Naehman; J, Appl, Physics
s, 25 (1959), P, 30? ).

A method of spreading rPL of powdered Al from the surface of a steel sheet (Japanese Unexamined Patent Publication No. 54-49936) and a method of obtaining an extremely thin Fe-Al alloy by a liquid quenching method (Japanese Unexamined Patent Publication No. 57-60024) have been proposed. ing.

However, both methods require the use of special manufacturing equipment. Therefore, it is undeniable that it lacks mass productivity as in the production of ordinary steel plates, and that the production cost is high. It has also been proposed to alloy Al-clad steel sheets by diffusion annealing, but there is a problem that voids and cranks are generated near the interface between the steel sheet and the Al sheet during the diffusion treatment. -A technology for obtaining a 1 alloy thin plate had not been established.

[Object of the Invention] The object of the present invention is to produce such a useful Fe-A I alloy thin plate industrially at low cost using ordinary equipment, and in particular to produce a thin plate of such a useful F e-A I alloy at a low cost, especially by laminating a steel plate and an Al plate. When a clad-rolled F e-A I laminated pressure-welded plate is used as a material and is diffusion annealed and alloyed, no cracks occur near the interface between the steel layer and the Al layer.

Another object of the present invention is to produce a high-quality F e-A 1 alloy thin plate with few voids.

[Structure of the invention]

According to the present invention, C content is 0.02% by weight or less and one or more of silica Ti, Nb, or Zr is added to 0.0% by weight.
A containing 1 to 0.8% by weight of A to be contained in the steel plate on at least one side of the steel vi (excluding stainless steel plates).
Al plates with a thickness equivalent to 110 ℃ are piled up, passed between rolls and subjected to a reduction of 30% or more to make a laminated press-welded plate.The obtained laminated press-welded plate is heated at a temperature of 600 to 1300℃ A method for manufacturing an Fe-A 1 alloy thin plate is provided, which comprises performing a diffusion treatment at a temperature such that the Al layer does not melt and is alloyed with steel.

In addition, using the laminated pressure-welded plate as a raw material, this is further rolled to the target thickness, and at that time, intermediate annealing is performed at 250 to 550°C before or during this rolling, and then at a temperature in the range of 600 to 1300°C. Provided is a method for manufacturing an Fe--Al alloy thin plate, which comprises performing a diffusion treatment under conditions such that the Al layer is alloyed with the steel without melting.

Furthermore, the laminated pressure-welded plate is annealed at 250 to 550°C and then formed into a desired shape (including the shape of a semi-finished product).
Provided is a method for producing an Fe-A I alloy thin plate molded product, which comprises performing a diffusion treatment under conditions where l1i is not melted but alloyed with steel.

[Effect]

Since the method of the present invention involves the operations of clad pressure welding and diffusion treatment, Fe-A I containing 3% or more Al, and in some cases 20% or more Al in Fe
Alloy thin plates can be manufactured industrially as strips in the same way as ordinary steel sheets.

In the diffusion process, by adjusting the degree, a uniform concentration of F with Al diffused uniformly in the temporary thickness direction can be obtained.
It can be made of e-A1 alloy plate.

It is also possible to obtain an Fe--Al alloy plate having A I U portions with different Al concentration distributions in the thickness direction.

In addition, it is possible to produce a FeAl alloy plate with a special structure that has an Al oxide film on the outermost surface and a layered Fe-A I alloy layer inside, making it relatively easy to manufacture products suitable for the application. can. Furthermore, if processing is performed before alloying by diffusion treatment, processed or semi-processed products of Fe-A I alloy with complex shapes, which have been difficult to produce in the past, can be easily produced.

In the present invention, C: 0.02% or less, Ti, N
b.

A steel plate containing 0.01 to 0.8% of one or more types of Zr is used as an Fe-based material, but if a steel plate with this composition is used, during the diffusion treatment of the press-welded plate with the Al plate. , voids and cranks that may occur near the interface between the m plate and the Al plate are prevented.

That is, the C content in the ig is 0.02% or less, and one or more of Ti, Nb, and Zr is added to the steel at 0.02% or less. When O is contained in an amount of 1 to 0.8%, these elements act to prevent the generation of voids and cracks in the products of the present invention, thereby producing high-quality F a-A 1 alloy thin sheets with excellent heat resistance and magnetic properties. can be manufactured.

[Detailed description of the invention includes: C: 0.02% by weight or less, Ti, Nb, Z
A steel plate or copper strip (hereinafter collectively referred to as steel plate) containing 0.01 to 0.8% by weight of one or more of r is used as one of the starting materials. Note that stainless steel sheets containing a large amount of chromium are not covered by the present invention. When carrying out the present invention, if a steel sheet with a high C content is used, 2. Voids tend to grow near the interface between the two, which in turn causes cracks to occur at the interface. Therefore, it is desirable that the C content in the steel sheet be as low as possible, but in the present invention, a C content of up to 0.02% is permissible. It has been found that by containing an appropriate amount of Ti, Nb, or Zr in the steel, it is possible to prevent the generation of voids and cranks near the interface between the steel layer and the Al layer during the diffusion treatment of the press-welded plate. One or two of these ingredients
If the content of seeds or more is less than 0.01%, no effect will be observed. On the other hand, even if it is contained in a large amount, the effect will be saturated, and the processability will deteriorate, making it difficult to obtain a press-welded plate, so it is limited to 0.8% or less. Although it is not necessarily clear why the inclusion of these components prevents voids and cracks from occurring near the interface, it is believed that these components are related to fixing C and producing stable carbides. Conceivable.

The Al plate (usually a thin plate or ribbon) used as the other starting material in the method of the present invention is preferably a pure Al plate; however, a normal Al plate contains some amount of Fe, Si, etc. These elements are also contained in steel sheets, so there is no problem even if such elements are contained.

Such an Al plate is superimposed on one or both sides of the above-mentioned steel plate, the thickness of which is selected so as to have the target Al content in the product alloy thin plate, and these are pressed together using rolls. At that time, it is desirable that the overlapping surfaces of both be subjected to purification treatment. In the pressure welding process of stacked plates using rolls, if the pressure reduction ratio is less than 30%, it is usually difficult to obtain a good pressure contact state between the steel plate and the Al plate. Therefore, it is necessary to set the pressure reduction ratio to 30% or more, thereby achieving lamination pressure welding between the steel plate and the Al plate.

In order to further improve the adhesion of this laminated press-welded plate, it is recommended to perform appropriate annealing treatment. Although this annealing treatment is not necessary in all cases, when the thickness of the press-welded plate exceeds approximately 1.5 am, Peeling may occur on the bonded surface when the plate is further cold-rolled in the primary process to reduce its thickness, or in some cases when it is formed into a product or semi-finished product. This can be prevented by annealing. This intermediate annealing is not effective unless a temperature of 250° C. or higher is employed. However, if the temperature exceeds 550°C, the steel layer of the pressure welding plate and the A
A thick all-glamella compound layer develops at the interface with the L layer, and during the next step of cold rolling, cranks are generated near this alloy layer, which may cause delamination. The annealing method may be batch annealing using a tight coil. in this case,
The annealing time is preferably about 1 to 20 hours. Other annealing methods may be used, but in any case, in order to prevent peeling during cold rolling, it is necessary to carry out the annealing at a temperature in the range of 250 to 550°C.

In this way, a laminated press-welded plate that has undergone the press-welding process, an annealed press-welded plate that has been subjected to intermediate annealing, or a cold-rolled press-welded plate that has been subjected to intermediate annealing before cold rolling or intermediate annealing during cold rolling, Once manufactured with the target amount of Al, it is subjected to a diffusion treatment in the ninth step. This diffusion treatment is a treatment for mutually diffusing the steel layer and the Al layer. When carrying out this diffusion process,
If the treatment temperature is less than 600° C., the diffusion of Al will not proceed sufficiently.

Moreover, when the temperature exceeds 1300°C, a molten layer forms in the diffusion alloy layer. Therefore, it is necessary to carry out the process in a temperature range of 600°C to 1300°C. Note that if the heating rate is increased during this diffusion treatment to a high temperature that is higher than the melting point of Al, AlN may melt at around 700°C.

When this Al layer melts, it causes a change in Al concentration in the direction of the plate surface due to sagging or accumulation. Therefore, it is necessary to prevent such melting of AlN as much as possible.

For this purpose, heat the aluminum at a temperature below the melting point of Al for a predetermined period of time.
For example, hold the temperature at 600 to 680℃ for more than 1 minute
It is preferable to form lJi into an alloy layer with a high melting point and then heat it to a higher temperature to perform a sufficient diffusion treatment. In the present invention, the phrase "performing the diffusion treatment under conditions in which rAlIi) is alloyed without melting" refers to this.

When carrying out this diffusion treatment, by appropriately selecting the temperature and treatment time within the above-mentioned treatment temperature range, and further by adjusting the atmosphere, steel plate products having nine different microstructures can be manufactured. For example, if sufficient diffusion is performed in a non-oxidizing atmosphere, Fe-
A1 alloy thin plates can be manufactured, and if the treatment is completed before sufficient diffusion, F with a high Al concentration in the surface layer can be produced.
e-A 1 alloy thin plate can be manufactured. Further, if diffusion annealing is performed without particularly avoiding surface oxidation, a special heat-resistant Fe-A 1 alloy thin plate having a rich Al oxide layer in the surface layer can be produced. In addition, after the diffusion process, F e
-A1 If the surface quality of the alloy thin plate becomes poor,
Good surface properties can be obtained by removing distortion by light cold rolling, or by polishing or polishing the surface.

In this way, according to the method of the present invention, Fe-A 1 alloy thin plates, which are difficult to manufacture using normal manufacturing methods, can be manufactured industrially. In particular, Fe-Al alloys are difficult to roll, not only by cold rolling but also by hot rolling. In the method of the present invention, a steel plate with good workability and an Al plate can be rolled in a press-welded state before Al is alloyed or after press-welding. Since the plate thickness is reduced by rolling, it is possible to cold-roll the plate to the target thin plate, and in some cases, it can be cold-processed into the shape of a product or semi-finished product.

Moreover, the Al content can be increased to 10% or more if necessary. Therefore, F e which is a high magnetic permeability alloy
-A 1 alloy thin plate and catalyst-supporting metal substrate used at high temperatures, as well as F e-A, which has excellent heat resistance and corrosion resistance.
1 alloy thin plate or alloy ribbon can be manufactured at low cost.

The oxidation resistance of the Fe-A 1 alloy thin sheet obtained by the method of the present invention is superior to that of stainless steel sheet (ferritic) even under severe conditions such as heating at 1000°C, as shown in the examples below. , and C is 0.02% or less, and one or more of Ti, Nb, and Zr is 0.0%
By using a tI4 plate containing 1 to 0.8%, voids and cracks are prevented from forming at the interface between the W4 layer and the Al layer during the diffusion treatment, so a high quality Fe-Al alloy thin plate can be manufactured.

A typical example of the present invention will be given below to show the characteristics of a steel plate obtained by the method of the present invention.

[Example 1] Plate thickness 0.6 whose chemical component values (weight %) are shown in Table 1
Both surfaces of the steel plate No. 1 were polished with a roll with a wire brush, and this was used as the core material, and the plate thickness was 0.15 mm.
An Al plate with IS alloy number 1050 that had been spray degreased with trichloroethane was used as the skin material.

The skin materials were superimposed on both sides of each core material with the thickness shown in Table 2, and rolled in a four-high rolling mill at the indicated reduction rate to the thickness shown in Table 2. and wound it on a coiler. The rolling speed was 10-30-7 minutes. The obtained pressure-welded plate coil was charged into a batch annealing furnace and subjected to intermediate annealing at 350°C for 10 hours, and then cold rolled to a plate size of 0.10 mm. A disk-shaped specimen with a diameter of 60 layers was taken from the obtained pressure-welded cold-rolled coil, and this disk-shaped specimen was heat-treated at 650°C for a time of 1000°C to 1150°C.
An oxidation test was conducted in which the sample was heated to a temperature of The results are shown in Table 2.

Note that during this high-temperature oxidation test, the diffusion of Al progresses, but the uniform diffusion ends at 1100 in the example of the present invention.
℃ for about 1 hour.

In addition, samples No. 4 and Nα5 were taken after heat treatment at 1100° C. for 25 hours, and their cross sections were observed under a microscope. The photographs are shown in Figs. 1 and 2.

As is clear from Table 2 (Sample 5, which is a comparative material that does not contain Ti, Nb, and Zr, shows an oxidation weight increase of more than IO+wg/c+m" at 1100°C for 200 hours, Sample 1, which is the invention material) No, 1.No, 2.Nct
3 and 4 show good oxidation resistance with an oxidation weight gain of less than 10111 g/c+m'' even in the oxidation test at 1100°C for 200 hours.Also, as seen in the photo in Figure 2, Ti
In sample floor 5, which is a comparative material that does not contain , Nb, or Zr, voids and cracks appear near the interface between the steel plate layer and the Al layer.

On the other hand, when a steel plate having the composition specified in the present invention is used, no voids or clutter are observed and the interface is uniform, as seen in the photograph of FIG.

[Example 2] The pressure rolled plates of samples Nt14 and Nt5 in Example 1 were cold rolled to a thickness of 0.05 m, and heat treated at 650°C for 1 hour, followed by diffusion treatment at 1100°C for 2 hours. This was carried out in a vacuum to obtain a FeAl alloy thin plate in which Al was uniformly diffused. After that, due to the shape correction of the plate, the elongation rate was reduced to 1.
0% light cold rolling was performed. A disk-shaped specimen of 60 s+-φ was taken from the obtained F e-A I alloy thin plate and exposed to air for 1 hour.
Oxidation experiments were conducted by heating to 000-1150°C. The results are shown in Table 3. In this example, the oxidation resistance of a Fe-A I alloy Fi plate in which Al was uniformly diffused was investigated.

As is clear from Table 3, the comparison material is 6-5IJS.
430 stainless steel plate has an oxidation temperature of 1100℃, 115
Comparative sample 5a, which showed an oxidation weight increase of 10 + wg/cm'' or more in less than 25 hours at 0°C and did not contain Ti, Nb, or Zr, had a
Although the oxidation weight increase is smaller and better than 430 steel plate, 12
00'c x 200 hours, 1150°C x less than 50 hours showed an oxidation weight gain of 10 mg/c1 or more, whereas sample No. 4a according to the present invention showed an oxidation weight increase of 1100°C x 2
00 hours, 10+ even at 1150°c x 50 hours
The weight gain due to oxidation is less than mg/c-, indicating good oxidation resistance.

In addition, in the comparison sample Na5a, when the pressure-welded cold-rolled sheet is subjected to the diffusion treatment, voids and cranks are generated near the interface between the m layer and the Al layer, as shown in Figure 2, and the shape of the sheet after the diffusion treatment is corrected. It was confirmed that sheet breakage is likely to occur during light cold rolling, which is performed for the purpose of rolling, and cracks may occur during processing such as punching and bending.

〔Effect of the invention〕

As mentioned above, according to the present invention, Fe-Al alloy thin plates, which were extremely difficult to make into thin plates, can be manufactured in a high quality state without cranks or voids, and moreover, they can be manufactured using existing production lines. Since it can be manufactured easily and inexpensively, it has great industrial significance.

[Brief explanation of drawings]

Figure 1 is a metallurgical micrograph showing the metallographic structure of a cross section of a steel plate after diffusion treatment using a steel plate containing Ti as a core material, and Figure 2 is a
It is a metallurgical micrograph showing the metal structure of a cross section of a steel plate after diffusion treatment using a steel plate that does not contain i, Nb, or Zr as a core material.

Claims (3)

[Claims] (1) C content is 0.02% by weight or less, and Ti, Nb
or one or more types of Zr from 0.01 to 0.8
At least one side of a steel plate containing % by weight is laminated with an Al plate having a thickness corresponding to the amount of Al to be contained in the steel plate, and this is passed between rolls and subjected to a reduction of 30% or more to perform lamination pressure welding. 600 to 1
Fe-
A method for producing an Al alloy thin plate. (2) C content is 0.02% by weight or less, and Ti, Nb
or one or more types of Zr from 0.01 to 0.8
At least one side of a steel plate containing % by weight is laminated with an Al plate having a thickness corresponding to the amount of Al to be contained in the steel plate, and this is passed between rolls and subjected to a reduction of 30% or more to perform lamination pressure welding. The obtained laminated press-welded plate is further rolled to the target thickness, and at that time, intermediate annealing is performed at 250 to 550°C before or during rolling, and then 60°C
A method for producing an Fe-Al alloy thin plate, which comprises performing a diffusion treatment at a temperature in the range of 0 to 1300°C under conditions such that the Al layer is alloyed with the steel without melting. (3) C content is 0.02% by weight or less, and Ti, Nb
or one or more types of Zr from 0.01 to 0.8
At least one side of a steel plate containing % by weight is laminated with an Al plate having a thickness corresponding to the amount of Al to be contained in the steel plate, and this is passed between rolls and subjected to a reduction of 30% or more to perform lamination pressure welding. 250-5 to the obtained laminated pressure-welded plate.
Fe- A method for producing aluminum alloy thin plate molded products.