JP2589586B2 - Manufacturing method of aluminum laminated steel sheet - Google Patents

Description

The present invention relates to a method for producing an aluminum laminated steel sheet by roll pressing and heating.

[Prior Art] Aluminum has excellent properties such as light weight, good workability and high corrosion resistance, and the ability to improve the mechanical properties by containing other metals. In terms of mechanical strength, it is inferior to other materials such as iron. In order to impart the properties of iron to aluminum, a clad material of an aluminum plate and a steel plate has been developed.

As a method of joining an aluminum plate and a steel plate, a rolling method, a diffusion joining method, and a brazing method are known, but continuous production of the brazing method is difficult. In the diffusion bonding method, heating is performed under a pressurized state of plastic deformation or less to induce diffusion bonding, but the atmosphere generally requires a vacuum. Rolling methods most suitable for continuous production include a cold rolling method and a hot rolling method. Joining by cold rolling generally requires a rolling rate of several tens of percent, and it is difficult to find appropriate rolling conditions. If the rolling ratio is lower than this, sufficient bonding cannot be obtained, and it is necessary to further perform a heat treatment after the rolling. However, at the time of hot rolling or heat treatment after cold rolling, a fragile alloy layer grows at the joining interface, thereby reducing workability.

In order to solve these drawbacks, by performing ion etching with a non-oxidizing low-pressure gas such as argon to remove oxides and then rolling, a method that does not require heat diffusion treatment at a low rolling rate, There is a method in which an insert material such as nickel or copper is inserted and rolled to suppress brittle alloys generated during heat treatment. In addition, copper is interposed at the interface between the steel sheet and the aluminum foil, and the two are joined by applying a pressure and a heat treatment below the plastic deformation (Japanese Patent Application No. 63-163).
No. 269545). Furthermore, there is a method in which nickel or copper plating is applied to the joint interface and then rolling is performed to suppress the formation of a brittle alloy (Japanese Patent Application No. 1-264856).

[Problems to be Solved by the Invention] When laminating aluminum and steel having greatly different plastic deformation amounts, the conventional cold rolling method generally requires a rolling reduction of 20% or more, and involves technical difficulties. .
In addition, when a heat diffusion treatment is performed to improve the bonding strength, a fragile alloy grows at the interface and deteriorates the workability of the laminated steel sheet. Further, the method of using an insert material for suppressing alloy formation requires a thickness of 10 μm or more for handling the insert material, which is inferior in economy. Furthermore, a method of removing oxides on an aluminum foil or a plate and a steel plate by ion etching, which does not require heat diffusion treatment, requires a vacuum apparatus and a vacuum technique, and has problems in continuity and economy.

[Means for Solving the Problems] It is an object of the present invention to continuously and economically provide an aluminum laminated steel sheet having excellent adhesion, workability, and work adhesion by low-pressure rolling.

The gist is steel plate coated with chromium, chromium-based alloy, chromium oxide or chromium hydrated oxide,
Alternatively, aluminum or aluminum alloy foil is superimposed on a steel plate coated with chromium, a chromium-based alloy, chromium oxide or hydrated chromium oxide, which has been previously heat-treated in a neutral or reducing atmosphere, and Is subjected to a heat treatment after being pressed and pressed, to produce an aluminum laminated steel sheet coated with aluminum or an aluminum alloy foil on one or both surfaces by diffusion bonding.

The steel sheet of the present invention is a steel sheet manufactured by a cold rolling method, and includes a low-carbon steel sheet, a chromium-added steel sheet, and a nickel-diffusion-treated steel sheet. Further, the plate thickness can be selected according to the application.

On the other hand, the aluminum or aluminum alloy foil is aluminum or an aluminum alloy having a thickness of 5 to 200 μm manufactured by a rolling method. Aluminum alloys include alloys containing magnesium, manganese, silicon, and copper. The reason why the thickness is limited is that workability decreases with a foil of less than 5 μm, which is not suitable for high-speed production.
If the thickness exceeds 200 μm, it is uneconomical in terms of material costs.

In manufacturing, the joint surface of the steel sheet is immersed in an alkaline solution, or subjected to cathodic or anodic electrolytic treatment to perform degreasing. In this case, processing conditions such as liquid composition, liquid concentration, processing temperature, and processing time are not particularly limited. In addition, a pickling treatment is performed to remove scale from the surface of the steel sheet. The conditions for pickling are not particularly limited, but excessive treatment may cause occlusion of hydrogen and may hinder uniformity of bonding. Unless these degreasing and pickling treatments are performed, the adhesion of the film is poor, and it is difficult to obtain an aluminum laminated steel sheet having sufficient bonding strength.

Next, the joining surface of the steel sheet is coated with chromium, an alloy containing chromium as a main component, chromium oxide or chromium hydrated oxide. The method of coating is not particularly limited, but a method by electroplating for chromium and a chromium alloy, and a method by chemical conversion for chromium oxide and hydrated chromium oxide are economical. At this time, the coating amount of chromium, chromium alloy, chromium oxide, and chromium hydrated oxide was 0.
02~0.5g / m ² are suitable. The amount of coating was limited to 0.0
If it is less than 1 g / m ^2, to a sufficient improvement effect can not be observed, 0.5
If the value exceeds g / m ² , the joining force is reduced.

When the chromium is coated by the electroplating method, when the steel sheet is subjected to a heat treatment, a gas or liquid such as hydrogen absorbed or absorbed by the electric treatment can be desorbed, and the uniformity of joining is improved. The atmosphere for the desorption treatment may be a non-oxidizing atmosphere represented by hydrogen, nitrogen or argon. In this atmosphere, the chromium-coated steel sheet is heated at a sheet temperature of 200 to 800 ° C. for 1 to 60 seconds. 200
If the temperature is lower than ℃, the desorption treatment is possible, but the treatment time becomes longer and the workability deteriorates. When the heating time is less than 1 second, the effect of the desorption treatment is not recognized even at a plate temperature of 800 ° C., and the effect is saturated when the heating time is 600 seconds or more. Preferably, it is 60 seconds, but it may take 600 seconds to improve the mechanical properties.

Next, the treated steel sheet and the aluminum or aluminum alloy foil are overlapped, and the whole is rolled down at a rolling reduction of 1 to 15%. The rolling reduction depends on the thickness and hardness of the steel plate and aluminum or aluminum alloy foil used. In a steel sheet that has not been subjected to an annealing treatment, a sufficient bonding force can be obtained at a rolling reduction of about 1%. Also, 15
If the rolling ratio is increased to at least%, wrinkles may occur. The aluminum or aluminum alloy foil can be coated on both sides or one side of the steel sheet, but when symmetrically laminated and pressed down, the warpage caused by the difference in linear expansion coefficient can be eliminated.

Then, in order to impart good adhesiveness to the aluminum laminated steel sheet temporarily joined by rolling, the aluminum or aluminum alloy foil coated from 400 ° C. is subjected to a heat treatment at a temperature lower than the melting point for 1 to 600 seconds. When the temperature is less than 400 ° C and less than 1 second, the effect of improving the adhesion is small. Joining takes more than 600 seconds, but the effect saturates. 60% for continuous high-speed production
Seconds or less are preferred. Of course, the heat treatment at a certain temperature or higher can also serve as softening annealing.

The atmosphere at the time of heating is not limited, and may be hydrogen, nitrogen, argon, or a mixed gas thereof. Further, heating may be performed in air. The pressing force at the time of heating is not particularly limited.

[Action] A strong oxide film exists on the surface of the aluminum or aluminum alloy foil. However, when the steel sheet is superimposed on a steel sheet and rolled, this oxide film is destroyed at the joint surface and a new surface appears, so that oxidation occurs. There is no need to remove the membrane. The chromium, chromium alloy, chromium oxide, or chromium hydrated oxide coating the steel plate covers the defects on the surface of the steel plate, and promotes brittle iron-aluminum intermetallic compound growth during the heat treatment promoted by the emerging surface. It is considered that an aluminum laminated steel sheet having excellent processing adhesion can be obtained in order to suppress the occurrence of the problem. In addition, since the chromium layer exists between aluminum and iron, the formation of a carburized layer is suppressed, and the heat treatment can be performed under conditions that can improve the machining characteristics deteriorated by rolling.

[Examples] The present invention will be specifically described with reference to Examples.

Example 1 A steel plate having a thickness of 0.30 mm subjected to a normal degreasing and pickling treatment was used.
Chromic anhydride 100 g /, sodium fluoride in a solution of 5 g / inclusive temperature 50 ° C., as a cathode the steel sheet at a current density of 4000A / m ^2, chromium metal, chromium hydrated oxide in the chromium content was treated 0.5 g / m ² and made like. The treated steel sheet is placed in a hydrogen gas atmosphere at a plate temperature of 200 ° C.
Heat treatment for 0 seconds, and then overlay aluminum foil with a thickness of 200 μm, roll at a rolling reduction of 5%, and heat the plate in air.
Heat treatment was performed at 400 ° C. for 60 seconds to obtain an aluminum laminated steel sheet.

Example 2 A 1.0 mm-thick steel sheet subjected to ordinary degreasing and pickling treatment was treated with 80 g of chromic anhydride, 0.3 g of sulfuric acid, and 0.6 g of borofluoric acid.
In a solution containing g / each at a temperature of 60 ° C., a steel plate was used as a cathode, and the chromium metal and chromium hydrated oxide were treated to have a chromium content of 0.01 g / m ² . The steel sheet subjected to this treatment is placed in an argon gas atmosphere at a temperature of 800 ° C. for 1 hour.
Heat treatment for 2 seconds, then overlaid with a 30μm thick aluminum alloy foil (JIS-3003), rolled at a rolling reduction of 12%,
Heat treatment was performed for 10 seconds at 550 ° C. in the air to obtain an aluminum laminated steel sheet.

Example 3 A 0.5 mm-thick steel sheet that had been subjected to ordinary degreasing and pickling treatments was placed in a solution containing 100 g of chromic anhydride and 5 g of sodium fluoride at a temperature of 50 ° C., and using the steel sheet as a cathode, The chromium hydrated oxide was treated so as to have a chromium content of 0.1 gg / m ² . Steel plate with this treatment and thickness 30μm
Was rolled at a rolling reduction of 8%, and subjected to a heat treatment in air at a temperature of 650 ° C. for 5 seconds to obtain an aluminum laminated steel sheet.

Example 4 A 0.6 mm-thick steel plate subjected to a normal degreasing and pickling treatment was used.
In a solution containing 5 g / sodium dichromate at a temperature of 60 ° C., the steel sheet was used as a cathode and the chromium and chromium oxide were treated to a chromium content of 0.5 g / m ² . Then, a 15μm thick aluminum alloy foil (JIS-1N30)
The whole was rolled at a rolling reduction of 5%, and then subjected to a heat treatment in a hydrogen gas atmosphere at a temperature of 400 ° C. for 30 seconds to obtain an aluminum laminated steel sheet.

Example 5 A steel plate having a thickness of 0.10 mm subjected to a normal degreasing and pickling treatment was used.
In an acidic solution at a temperature of 60 ° C. containing 10 g / ammonium dichromate, the steel plate was treated as an anode and the amount of chromium oxide was adjusted to 0.01 g / m ² in terms of chromium.
% And hydrogen gas at 5% in an atmosphere containing 5%
Under the conditions described above for 30 seconds. A steel plate subjected to this treatment and an aluminum alloy foil (JIS-3004) having a thickness of 50 μm are overlapped and rolled at a rolling reduction of 1%, and then subjected to a heat treatment at a temperature of 500 ° C. for 30 seconds in a nitrogen gas atmosphere. An aluminum laminated steel sheet was obtained.

Example 6 A steel plate having a thickness of 0.10 mm subjected to a normal degreasing and pickling treatment was used.
Chromous chloride 200g / Nickel chloride 25g / Sodium citrate 50g / Ammonium chloride 130g /
The chromium-nickel alloy was plated at 0.5 g / m ² in terms of chromium amount in an acidic solution containing 40 ° C. at a temperature of 40 ° C. using the steel plate as a cathode. Steel plate with this treatment and thickness 100
5 µm aluminum alloy foil (JIS-1085)
After rolling at a draft of 500 mm, the temperature of the sheet is 500 ° C in a nitrogen gas atmosphere.
Heat treatment was performed for 30 seconds under the conditions described above to obtain an aluminum laminated steel sheet.

The obtained aluminum laminated steel sheet, after attaching a 1 mm square grid on the aluminum surface until it reaches the base steel part, overhanging 6 mm or 8 mm on the aluminum side with an Erichsen tester, forcibly peeling off with cellophane tape,
The processing adhesion was tested.

As a result, in the aluminum laminated steel sheets according to the present invention of Examples 1 to 6, peeling of the aluminum or aluminum alloy foil from the steel sheet was not recognized.

[Effect of the Invention] By the method for producing an aluminum laminated steel sheet according to the present invention,
Aluminum or aluminum alloy foil and steel sheet are uniformly joined at a low rolling rate, and diffusion processing can also serve as softening annealing, making aluminum laminated steel sheets excellent in adhesion, workability and work adhesion economically. Obtained.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-128180 (JP, A) JP-A-53-102840 (JP, A) JP-A-63-40689 (JP, A) JP-A-54- 120258 (JP, A) JP-B 34-5408 (JP, B1) JP-B 37-70 (JP, B1)

Claims (2)

(57) [Claims] 1. A steel sheet containing chromium, chromium alloy, chromium oxide or chromium hydrated oxide in an amount of 0.01 to 0.5 g in terms of chromium.
/ m ² was coated, in a neutral or reducing atmosphere, 200 to 800 ° C., 1
Heat treatment for ~ 600 seconds, then laminate aluminum or aluminum alloy foil with a thickness of 5 ~ 200μm, press the whole at a reduction rate of 1 ~ 15%, then lower than 400 ℃ below the melting point of the coated aluminum or aluminum alloy At the temperature of
A method for producing an aluminum laminated steel sheet, comprising performing heat treatment for 1 to 600 seconds. 2. A steel sheet containing 0.01 to 0.5 g of chromium, chromium alloy, chromium oxide or chromium hydrated oxide in chromium content.
/ m ² coating, and then laminate aluminum or aluminum alloy foil with a thickness of 5 to 200 μm, and reduce the whole to a rolling reduction of 1 to 15
%, Followed by heat treatment at a temperature lower than the melting point of the coated aluminum or aluminum alloy from 400 ° C. for 1 to 600 seconds.