JPH0730430B2 - Aluminum alloy plate for drawing and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy soft plate for drawing used for packaging containers such as bottle caps and closures, bases for fluorescent lamps, and other various articles and the like. The present invention relates to a manufacturing method.

2. Description of the Related Art A soft material (O material) of general aluminum metal is used for applications such as bottle caps and closures, or bases for fluorescent lamps that are drawn and processed. And conventionally, as such an aluminum alloy,
JIS 1100 alloy, JIS 3003 alloy or AA8011 alloy are mainly used. When these aluminum alloys are used for the above-mentioned applications, generally, an ingot is obtained by a DC casting method (semi-continuous casting method), the ingot is subjected to a homogenization treatment, then hot-rolled, and then cooled. It is usual to carry out hot rolling and annealing. The conventional aluminum alloy soft plate for draw forming manufactured in this manner has good draw formability and also has a certain strength.

Problems to be Solved by the Invention As described above, the DC casting method has been applied to the production of the conventional aluminum alloy soft plate for drawing, but in recent years, due to the demand for cost reduction and thinning, the continuous casting method ( A thin plate continuous casting and rolling method) is applied to directly obtain a cast plate having a plate thickness of about 3 to 15 mm from a molten alloy and a method of omitting hot rolling is under study. However, when the continuous casting method is applied, since the cooling rate during casting is high, the solid solution amount of the alloying elements in the aluminum matrix is large, and therefore, when the temperature rising rate during annealing after cold rolling is slow, The crystal grains become an abnormally grown structure, the drawability deteriorates, and there is a problem that rough skin and flow lines easily occur during the draw forming, and in this case, the earing rate at the time of draw forming related to the forming yield also occurs. There is a problem that it becomes expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aluminum alloy plate having good draw formability and low earring rate during draw forming while applying continuous casting. Is.

Means for Solving the Problems The inventors of the present invention have conducted extensive experiments and studies to achieve the above-mentioned objects, and as a result, appropriately adjust the component weaving of the alloy in the case of applying continuous casting, and at the same time the final cold It was found that by appropriately adjusting the solid solution amount of Fe in the aluminum matrix in the state before rolling, it is possible to obtain an Al alloy plate for drawing forming having good drawing formability and low earring rate, and making the present invention. I arrived. In addition, in the process of producing alloys, when the continuous casting method is applied to increase the cooling rate during casting, the intermediate heat treatment during cold rolling is rapidly heated and rapidly cooled. It was found that an Al alloy plate for draw forming having excellent draw formability and low earring rate can be obtained by repeating the above two or more times, and the present invention has been accomplished.

Therefore, the inventions of claim 1 and claim 2 are in a state before final cold rolling and subsequent final annealing.
The composition of the Al alloy plate and the amount of solid solution of Fe are defined, and the inventions of claims 3 and 4 are processes of a method for producing an aluminum alloy plate for drawing by applying a continuous casting method. Is defined.

Specifically, the invention of claim 1 is an Al alloy sheet made by using a continuously cast sheet continuously cast at a cooling rate of 50 ° C./sec or more, and further, final cold rolling with a rolling rate of 30% or more. And in the Al alloy plate that is subsequently subjected to final annealing at a temperature of 350 ° C. or higher and is used for draw forming, Mg0.
1-2.0wt%, Mn0.1-2.5wt%, Fe0.1-2.5wt%, balance Al and unavoidable impurities, and Fe solid solution amount in the aluminum matrix is 200ppm or less It is characterized by.

Further, the invention of claim 2 is an Al alloy plate produced by using a continuously cast plate continuously cast at a cooling rate of 50 ° C./sec or more, and further, the final cold rolling with a rolling rate of 30% or more and the subsequent cold rolling. In an Al alloy plate that is subjected to final annealing at a temperature of 350 ° C or higher and is used for draw forming, Mg 0.1 to 2.0
wt%, Mn 0.1-2.5 wt%, Fe 0.1-2.5 wt%, and
It contains 1 or 2 kinds of Cu0.05-1.0wt% and Zn0.1-1.0wt%, the balance consists of Al and unavoidable impurities, and the solid solution amount of Fe in the aluminum matrix is 200ppm or less. It is characterized by.

Furthermore, the manufacturing method of the Al alloy plate for drawing according to the invention of claim 3 is Mg0.1-2.0wt%, Mn0.1-2.5wt%, Fe0.1-
An aluminum alloy containing 2.5 wt% and the balance of Al and unavoidable impurities is continuously cast at a cooling rate of 50 ° C./sec or more to obtain a continuously cast plate having a plate thickness of 3 to 15 mm, and then cold rolling. Then 10 ℃ to a temperature in the range of 500-620 ℃
The final cooling is performed by repeating the heat treatment in which the temperature is raised at a heating rate of at least / sec or more and immediately or held at that temperature for 120 seconds or less and then cooled at a cooling rate of at least 10 ° C / sec two or more times. It is characterized in that the solid solution amount of Fe in the aluminum matrix immediately before hot rolling is adjusted to be 200 ppm or less, and the rolling ratio of the final cold rolling in the repeating step is 30% or more. is there.

And the manufacturing method of the Al alloy plate for draw forming according to the invention of claim 4 is Mg0.1-2.0wt%, Mn0.1-2.5wt%, Fe0.
1-2.5wt%, and Cu0.05-1.0wt%, Zn0.1-1.
An aluminum alloy containing 1 wt% or 2 wt% of 0 wt% and the balance consisting of Al and unavoidable impurities is continuously cast at a cooling rate of 50 ° C./sec or more to obtain a continuously cast plate having a plate thickness of 3 to 15 mm. Cold rolling followed by heating to a temperature in the range of 500 to 620 ° C at a heating rate of 10 ° C / sec or more, immediately or after holding at that temperature for 120 sec or less, then 10 ° C / s
The heat treatment of cooling at a cooling rate of ec or more is repeated twice or more to adjust the amount of Fe solid solution in the aluminum matrix to 200 ppm or less immediately before the final cold rolling. The feature is that the final cold rolling rate in the process is set to 30% or more.

Work The alloy components in the Al alloy plate for draw forming of each invention of the present application are mainly added to enhance the strength of the material and to stabilize the directionality and enhance the pilfer, that is, the tearing property when used for a cap or the like. First, the reasons for limiting the components in the Al alloy sheet for drawing according to the first aspect of the invention will be described.

Mg: Mg is an element effective as a solid solution in the aluminum matrix and increasing the strength of the O material. However, in the case of the method of the present invention, the cooling rate at the time of casting is increased to forcibly form a solid solution with other components, and the heating and cooling at the time of annealing are also accelerated. Therefore, not only Mg but also other alloy elements effectively act to improve the strength, so that it is not necessary to add 4 wt% as in the case of DC casting. Here, if the amount of addition of Mg is less than 0.1%, abnormal grain growth may occur during rapid heating and annealing, which may impair drawability. On the other hand, if the amount of addition of Mg exceeds 2.0 wt%, the cold rolling property is deteriorated, and ear cracks are apt to occur during cold rolling, which lowers the yield and causes operational problems. Therefore, the amount of Mg added is set within the range of 0.1 to 2.0 wt%.

Mn: Mn is an element that contributes to the improvement of strength and is effective in improving the tearability. In particular, in the material for drawing forming used for bottle caps, closures, etc., which are used in this invention, a material having a certain level of strength and excellent tearability is required, and therefore Mn
Is required. If Mn is less than 0.1 wt%, the above effect cannot be obtained. On the other hand, if it exceeds 2.5 wt%, the above effect can be obtained, but the cold rolling property is extremely deteriorated and the castability is extremely deteriorated. Therefore, the amount of Mn added is 0.1 to 2.5 wt.
Within the range of%.

Fe: Fe is forced to form a solid solution during casting like Mn,
It is an element that acts very effectively in controlling the directionality and improving the tearability by limiting the solid solubility in relation to the process after casting. Although the addition of Fe significantly reduces the solid solution amount of Mn, the reduction of the solid solution amount of Mn, on the contrary, produces fine precipitates. It is also useful for improving. If the Fe addition amount is less than 0.1 wt%, these effects cannot be obtained, while 2.5
If Fe is added in excess of wt%, the precipitate will be coarsened and it will be difficult to control the O material strength. Therefore, the amount of Fe added is 0.1-
Within the range of 2.5 wt%. The range in which the effect of adding Fe is most effective is within the range of 0.8 to 1.3 wt%, and therefore the amount of adding Fe is particularly preferably within the range of 0.8 to 1.3 wt%.

As described above, in the Al alloy plate of the invention of claim 1, Mg, Mn, Fe are added as essential alloy components, strengthening by solid solution of Mg, and strength by dispersion strengthening effect of Mn, Fe which are transition elements In addition to making improvements, we have taken into consideration the stabilization of directionality, the improvement in tearability required as a material for draw forming, and the improvement in cold rolling property.

Furthermore, in the aluminum alloy plate for draw forming according to claim 2, Cu and / or Zn is added in addition to the above-mentioned Mg, Mn, Fe, and M is added.
In addition to the above-mentioned effects due to g, Mn, and Fe, we are also working to improve the strength after baking by utilizing age hardening during baking. Next, Al for draw forming according to the invention of claim 2
The reason for limiting the addition amounts of Cu and Zn in the alloy plate will be described.

Cu: Cu promotes age hardening during coating baking as described above, and is effective in improving the strength of the plate after coating baking. This effect occurs in the precipitation process of Al-Cu-Mg-based precipitates. To achieve this effect, at least 0.05
It is necessary to add more than wt% Cu. On the other hand, when Cu is added in an amount of 1.0 wt% or more, age hardening can be easily obtained, but work hardening easily occurs during cold rolling, and draw formability is impaired. Therefore, the addition amount of Cu is set to the range of 0.05 to 1.0 wt%.

It is well known that Zn: Zn can also be expected to age harden due to the interaction with Mg and Cu.In this invention, addition of Zn also improves the strength of the plate after coating baking by age hardening during coating baking treatment. I am trying to If the addition amount of Zn is less than 0.1 wt%, the result cannot be obtained, while if it exceeds 1.0 wt% Zn
If added, the strength is improved, but the work hardenability becomes strong and the draw forming workability is extremely impaired. Therefore, the addition amount of Zn is set within the range of 0.1 to 1.0 wt%.

The balance of each of the above components is the same in any invention of the present application.
Al and inevitable impurities may be used.

In addition, in a usual aluminum alloy, a small amount of Ti or Ti and B may be added for refining the crystal grains of the ingot. Even in the aluminum alloy hard plate for forming of the present invention, a small amount of Ti or Ti And B may be contained. However, when Ti is added, the addition amount is 0.
If it is less than 01%, the effect of Ti addition cannot be obtained, and if it exceeds 0.50%, TiAl ₃ crystallizes and impairs the formability.
It is preferably in the range of 0.50%. In addition, when B is added together with Ti, if the addition amount of B is less than 1 ppm, there is no result of addition of B, while if it exceeds 1000 ppm, coarse particles of TiB ₂ are mixed and formability is impaired, so B is 1 ppm to 1000 ppm.
It is preferably within the range.

Further, in the aluminum alloy sheet for draw forming according to the first and second aspects, the solid solution amount of Fe dissolved in the aluminum matrix before the final cold rolling must be 200 ppm or less. That is, the Al alloy sheet of claims 1 and 2 is then subjected to a final cold rolling of 30% or more, and subsequently subjected to final annealing at a temperature of 350 ° C or more to obtain a predetermined sheet thickness as a soft sheet and draw forming. However, as a plate in the state before the final cold rolling, the solid solution amount of Fe in the aluminum matrix needs to be 200 ppm or less. The amount of solid solution of Fe is closely related to the directionality of drawing process, and if the amount of solid solution of Fe exceeds 200ppm, the ears become strong at 45 ° during drawing process, and as an Al alloy plate for drawing process. Becomes inappropriate. Note that the amount of solid solution of Fe at this stage is preferably in the range of 80 to 160 ppm,
In this case, it is possible to obtain a so-called non-ear material having no ears during the drawing process after the final treatment.

Next, the invention of claims 3 and 4, that is, the invention of a manufacturing method will be described.

First, a melt of an alloy having the above-described composition is melted according to a conventional method, and a thin plate continuous casting method (continuous casting and rolling method)
Continuous casting method such as the above is used to continuously cast a plate having a plate thickness of 3 to 15 mm, and wound into a coil. The cooling rate during this continuous casting needs to be a high cooling rate of 50 ° C./sec or more. Originally, Fe and Mn, which are transition metals, are difficult to form a solid solution in aluminum, and most of them crystallize when the cooling rate during casting is low. In order to achieve the effect, a cooling rate of 50 ° C / sec or more is required. Note that Fe crystallizes or precipitates to some extent even at a cooling rate of 50 ° C./sec or more. However, within the composition range of the present invention, 50 ℃ / sec
At the above high cooling rate, crystallized substances and precipitates become extremely fine, which is rather advantageous in terms of strength improvement.

For the continuously cast plate obtained as described above, cold rolling and heat treatment (annealing) are subsequently repeated twice or more. That is, after performing primary cold rolling on a continuous cast plate to obtain an intermediate plate thickness, the first heat treatment (intermediate heat treatment)
The final heat treatment may be performed after the final cold rolling is performed to obtain the product sheet thickness, or the first cold rolling and the first heat treatment may be performed, and then the cold rolling and the heat treatment may be further performed. You may repeat 2 times or more. The heat treatment in this process improves the rolling property without impairing the age hardening by solid solution Cu, Zn, Mg and the dispersion strengthening effect by the transition metals Fe, Mn, and also improves the directionality and draw formability. It is what is done. In this heat treatment, both heating rate and cooling rate must be 10 ° C / sec or more so that precipitation does not occur during heating (heating) and cooling, and a completely recrystallized and uniform structure In order to obtain the required temperature, it is necessary to reach the temperature of 500 ℃ / sec or more.
If the temperature exceeds ℃, eutectic melting may occur and plate breakage may occur during operation. Therefore, the ultimate temperature was set within the range of 500 to 620 ℃. Holding at a temperature within the range of 500 to 620 ° C
It is easier to control the precipitation if it is as short as possible, but 120 seconds or less is acceptable. Note that such a heat treatment of rapid heating and rapid cooling of 10 ° C./sec or more and no holding or a short-time holding of 120 sec or less can be achieved by using a continuous annealing furnace.

Of the cold rolling in the above process, the final cold rolling (before the final heat treatment) needs to have a rolling rate of 30% or more. If the final cold rolling ratio is less than 30%, it is difficult for the crystal orientation to rotate during the final annealing, and the 45 ° ear during drawing forming after annealing becomes high.

Furthermore, in the above process, the amount of Fe solid solution in the aluminum matrix in the plate just before the final cold rolling was 20%.
It is adjusted to 0 ppm or less, preferably 80 to 160 ppm. By doing so, it is possible to obtain a material having a low earring rate and excellent directivity during the drawing process.

As described above, the cold rolling and the heat treatment of the rapid heating / quenching are repeatedly performed twice or more on the continuous cast plate, and the solid solution amount of Fe in the aluminum matrix before the final cold rolling is adjusted, It is possible to obtain an Al alloy sheet having a low earring rate, a fine crystal grain, a high O material strength, and excellent drawability and workability, which are necessary conditions for a draw forming material.

In addition, since the solution treatment effect can be obtained by the heat treatment (annealing) by the above-mentioned rapid heating and quenching, after the final annealing, as a stabilization treatment, a heat treatment at 100 to 250 ° C. (artificial aging treatment) may be performed, In this way, a material having higher strength can be obtained.

Examples [Example 1] Compositions of alloys A to D within the composition range defined in the invention of claim 1 of the present application as shown in Table 1 and JIS 1100 alloy which is a conventional alloy Regarding the alloy with the code E of
Applying the process shown in Table 2, the final plate thickness 1.0m
A rolled plate of m was obtained. Here, in Table 2, the process conditions for the alloys A and C are within the process condition range of the invention of claim 3 of the present application, and the process conditions for the alloys B, D and E are outside the process condition range. Table 3 shows the amount of Fe solid solution in the aluminum matrix in each plate immediately before the final cold rolling in this manufacturing process, and also includes the mechanical properties and the flow line of each finally obtained rolled plate. Table 3 shows the results of examination of redrawability.

As shown in Table 3, in the Al alloy plate for the draw forming process (alloy code A, C: example of the present invention) manufactured according to the process conditions of the present invention, compared with the rolled plate according to the conventional example (1100 alloy) or the comparative example. Then, it is clear that the O-material is a material which is remarkably excellent in strength, has a low earing rate at the time of draw forming, and is also excellent in draw formability including the flow line.

[Example 2] As shown in Table 4, the alloys of the symbols F to H within the component composition range defined in the invention of claim 2 of the present invention and the alloy composition of the conventional alloy AA8011 alloy I Alloy and JIS
A process as shown in Table 5 was applied to the 1100 alloy and the alloy having the code E to obtain a rolled plate having a final plate thickness of 0.22 mm. Here, the process conditions for the alloys F and H in Table 5 are within the process condition range of the invention of claim 4 of the present application, and the process conditions for the alloys G, I and E are outside the process condition range. Table 6 shows the Fe solid solution amount in the aluminum matrix of each plate immediately before the final cold rolling in the manufacturing process, and corresponds to the coating baking treatment (baking) for each finally obtained rolled plate. 200 ° C x 2
Table 6 shows the results of examining the mechanical properties after the stabilizing heat treatment for 0 min and the drawability including the flow line.

As shown in Table 6, the Al alloy sheet for alloy forming (alloy code F, H: Inventive Example) manufactured according to the process conditions of the present invention is coated with a rolled sheet according to a conventional example or a comparative example. It is clear that the strength is improved after the baking treatment, and the drawability including the flow line generation condition is remarkably excellent.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, the strength after forming is superior to that of the conventional material, and the drawability is excellent even though continuous casting is applied, and the ear ratio and the flow rate are improved. It is possible to obtain an Al alloy plate for drawing that is excellent in terms of line. Therefore, according to the present invention, it is possible to reduce the thickness and increase the strength of packaging containers such as bottle caps and closures, bases of fluorescent lamps, and other various articles.

Claims (4)

[Claims] 1. An Al alloy sheet produced by using a continuously cast sheet continuously cast at a cooling rate of 50 ° C./sec or more, and further, final cold rolling with a rolling rate of 30% or more and subsequent 350
Al alloy plate that is subjected to final annealing at a temperature of ℃ or higher and used for drawing forming contains Mg 0.1 to 2.0 wt%, Mn 0.1 to 2.5 wt%, Fe 0.1 to 2.5 wt% However, the balance is Al and inevitable impurities, and the amount of solid solution of Fe in the aluminum matrix is 200 ppm or less, an Al alloy plate for drawing. 2. An Al alloy sheet produced by using a continuously cast sheet continuously cast at a cooling rate of 50 ° C./sec or more, and further, final cold rolling with a rolling rate of 30% or more and subsequent 350
Al alloy plate that is subjected to final annealing at a temperature of ℃ or higher and used for drawing forming contains Mg 0.1 to 2.0 wt%, Mn 0.1 to 2.5 wt%, Fe 0.1 to 2.5 wt% In addition, it contains one or two of 0.05 to 1.0 wt% Cu and 0.1 to 1.0 wt% Zn, the balance being Al and inevitable impurities, and the solid solution amount of Fe in the aluminum matrix is 20.
An Al alloy plate for draw forming, characterized by being 0 ppm or less. 3. Mg0.1-2.0wt%, Mn0.1-2.5wt%, Fe0.1
An aluminum alloy containing ~ 2.5 wt% and the balance Al and unavoidable impurities is continuously cast at a cooling rate of 50 ° C / sec or more to form a continuously cast plate with a plate thickness of 3 to 15 mm, and then cold rolled. , Followed by 10 to a temperature in the range of 500-620 ° C
The temperature is raised at a heating rate of ℃ / sec or more and held immediately or at that temperature for 120 seconds or less, and then cooled at a cooling rate of 10 ℃ / sec or more. The amount of Fe solid solution in the aluminum matrix immediately before cold rolling is adjusted to be 200 ppm or less, and further the rolling ratio of the final cold rolling in the repeating step is 30% or more. Manufacturing method of Al alloy plate for forming process. 4. Mg0.1 to 2.0 wt%, Mn0.1 to 2.5 wt%, Fe0.1
~ 2.5wt%, and Cu0.05-1.0wt%, Zn0.1-1.0
An aluminum alloy containing 1% or 2% by weight and the balance being Al and unavoidable impurities is continuously cast at a cooling rate of 50 ° C./sec or more to obtain a continuously cast plate having a plate thickness of 3 to 15 mm. Cold rolling followed by heating to a temperature in the range of 500 to 620 ° C at a heating rate of 10 ° C / sec or more, immediately or after holding at that temperature for 120 sec or less, then 10 ° C / s
The heat treatment of cooling at a cooling rate of ec or more is repeated twice or more to adjust the amount of Fe solid solution in the aluminum matrix to 200 ppm or less immediately before the final cold rolling. A method for producing an Al alloy sheet for drawing, wherein the final cold rolling rate during the process is 30% or more.