JPS63286546A - Aluminum alloy plate for can and its production - Google Patents

Abstract

PURPOSE:To develop an Al alloy thin plate material as a can material for drink and food having excellent strength and moldability by adding Cu, Si and other elements to an Al-Mg alloy, thereby providing aging hardenability to the titled plate. CONSTITUTION:The ingot of the Al alloy contg., by weight, 3-6% Mg, 0.6-1.5% Cu, 0.05-0.7% Si, 0.05-1.0% Mn and 0.1-0.7% Fe and contg. one or more kinds among 0.01-0.3% Cr, 0.05-0.5% Zr, 0.005-0.3% Ti and 0.0001-0.003% B is worked to the plate material having specific thickness by hot rolling and cold rolling. Said plate materials made of Al alloy is heated to 400-500 deg.C, is retained for 2-120sec at this temp., is thereafter cooled to the room temp. at >=10 deg.C/hr cooling ratio and is cold rolled to 0.25mm final plate thickness. Said material is applied to aging treatment at 100-250 deg.C if necessary, by which the thin plate material made of Al alloy for a can having excellent strength and moldability is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an aluminum alloy plate with excellent strength and formability used for metal cans for beverages and foods, and a method for manufacturing the same.

[Conventional technology and its problems]

Metal cans used for beverages or foods consist of a can body and a can lid.The can body is processed into a cup shape by D [forming], and the can lid is joined to the cup after a tab is attached by rivet molding. Therefore, Af-Mn-Mg type 3004, which has excellent deep drawability and ironing workability, is used as the can body material, and Al-Mg type 5052 and Al-Mg type 5052, which have excellent rivet formability and opening properties, and strength, are used for the can lid. 5082 etc. are commonly used. Recently, as seen in Japanese Patent Application Laid-open No. 50141, alloys have been developed in which a trace amount of Cu is added to impart age hardenability.

In recent years, demand for aluminum cans has increased to 2. However, in order to reduce manufacturing costs, materials are being made thinner, and there is a strong desire for higher strength alloy plates.

However, although the above alloys have excellent formability, their strength tends to decrease due to the heating during painting (hereinafter referred to as baking), and they are insufficient in terms of strength to withstand future thinning. be. In addition, in JP-A No. 60-50141, Cu is added to increase the strength, but it is insufficient in terms of strength for the thinning of walls of 0.3 m or less, which is expected in the future, and processing is performed to the extent that the strength is improved. However, there is a problem that the properties of this alloy are somewhat poor, and there is a need to develop an alloy that can satisfy both strength and formability.

[Problem that the invention seeks to solve]

As a result of studying the above-mentioned problems, the present invention was developed as a result of the conventional alloys being non-heat-treatable alloys, which soften and lose strength during baking when used for metal cans. We have developed an aluminum alloy plate for cans that can be hardened to improve its strength, and a method for manufacturing the same.

[Means and effects for solving the problems] The present invention was made in view of the above problems, and the first invention is Mg3
~6wt%, Cu0.6~1.5wt%, Si0.0
5 to 0.7 wt%, Mn 0.05 to 1.0 wt%,
Contains Fe 0.1~0.7wt% and Cr0.01~
0.3wt%, Zr0.05-0.5nt%, Ti
0.005~0. ht%, B0.0001~0.00
The second invention is an aluminum alloy plate for cans containing at least one of Mg3 to 6wt%, and the remainder being unavoidably contained impurities.
0.6-1.5wt%, Si0.05-0.7wt%
, Mn 0.05-1.0wt%, Fe0.1-0.
Contains 7wt%, Cr0.01-0.3wt%, Zr
0.05-0.5wt%, Ti 0.005-0.
3wt%, B0.0001 to 0.003wt%, and the remainder is unavoidably contained impurities and Al after hot rolling or cold rolling 4
A method for producing an aluminum alloy plate for cans, which comprises heating to 00 to 500°C, holding for 2 seconds to 120 minutes, cooling to room temperature at a rate of 10°C/hr or more, and cold rolling to final thickness. and the third invention is Mg3-6wt%, Cu0
．． 6-1.5wt%, Si0.05-0.7wt%,
Mn0.05-1.0wt%, Fe 0.1-0.7
wt% and Cr0. O1-0.3wt%, Zr0.
05-0.5-t%, Ti0.005-0.3wt%,
Impurities containing any one or more of 80.0001 to 0.003 wt%, with the remainder unavoidably included, and A2
400-50 after hot rolling or cold rolling the alloy consisting of
Heat to 0℃, hold for 2 seconds to 120 minutes, then heat at 10℃/h
This is a method for producing an aluminum alloy plate for cans, which comprises cooling the aluminum alloy plate to room temperature at a rate higher than r, cold-rolling it to the final thickness, and then aging it at a temperature of 100 to 250'C.

The present invention imparts age hardenability and improves strength by adding Cu to an An-Mg alloy, and improves formability by adding St. That is, the present invention aims to strengthen the alloy by molding an Al-Mg-Cu based compound, and adds Fe and Mn to form Af-Mn-F.
This promotes the precipitation of e-3i compounds to provide solid lubricity during molding.

Next, the reason for limiting the ingredients of the present invention will be described.

First, Mg is one of the hardening elements, but it has no effect if it is less than 3 wt%, and if it exceeds 6 wt%, it inhibits workability. Cu
combines with Mg to form an Al-Cu-Mg-based compound and contributes to strengthening, but if it is less than 0.6 wt%, the effect is small, and if it exceeds 1.5 wt%, quenching sensitivity increases and strength is impaired. It will be done. Si is AI! , , Mn, combines with Fe to A/! -Mn-Fe-5i based compounds are molded to improve moldability, but if it is less than 0.05wt%, the effect is small, and if it exceeds 0.7wt%, toughness decreases and quenching sensitivity is increased to ensure sufficient strength. is not obtained. Fe is Q, and if it is less than 1 wt%, it will not have sufficient effect to precipitate Al-Mn-Fe-based compounds, and if it exceeds 0.7 wt%, it will form a huge Al-Mn-Fe-based compound. ,
Impairs toughness and formability. Cr contributes to improving corrosion resistance, but if it is less than 0.01wt%, the effect is small;
%, a giant intermetallic compound is formed with AN, reducing the ductility required for forming. Zr suppresses recrystallization during material processing (especially during hot rolling) and contributes to improving formability by obtaining fine fibers in the processing direction.
If it is less than t%, the effect is small, and if it exceeds 0.5wt%, it becomes a huge AI! , -Zr- type compounds are formed and the moldability is inhibited. Ti has the effect of refining the crystal grains of the ingot, but 0
．． If it is less than 0.005wt%, it has no effect, and 0.3wt%
If it exceeds this amount, a huge intermetallic compound is formed with Af, impairing the rolling properties and formability of the material. Like Ti, B contributes to grain refinement in the ingot, but if it is less than 0.0001 wt%, the effect is small, and if it exceeds 0.003 wt%, coarse T
iBz particles are formed and the toughness is reduced.

Next, the manufacturing method of the present invention will be explained.

After hot or cold rolling aluminum alloy with the above composition 4
The purpose of heating to 00 to 550°C is to perform solution treatment, and at a temperature below 400°C, Mg is heated.

Solid solution of Cu is not promoted and sufficient reinforcement cannot be achieved.

Moreover, if the temperature exceeds 550°C, the crystal grains will become coarse and roughness will occur during molding of the final product. The holding period was set from 2 seconds to 120 minutes because there is no solution treatment effect if the holding period is less than 2 seconds.
This is because, if it exceeds 100%, the crystal grains will become coarser.

The cooling rate after heating was 10℃/hr.
If it is less than r, the cooling process will be A/! This is because the equilibrium phase of the -Mg-Cu system precipitates and does not contribute to strengthening. Also, aging treatment at a temperature of 100 to 250°C after cold rolling to the final thickness is A j! -M g - This is to promote fine and uniform precipitation of the Cu-based compound and harden it at 100°C.
If it is less than 250°C, the effect will be small, and if it exceeds 250°C, coarse particles will precipitate and the strength will be lower than that without heat treatment.

[Example 1] An embodiment of the present invention will be described below.

An aluminum alloy having the composition shown in Table 1 was melted and cast into a slab with a thickness of 500 m by a water-cooled casting method, which was homogenized and then hot-rolled into a plate with a thickness of 2.5 rrm. After being cold rolled into a 0.8mm plate, it was solution-treated by holding it at 520°C for 10 seconds in a continuous annealing furnace, air-cooled to room temperature, and then cold rolled to a thickness of 0.25n.
Finished as a +n+ board.

The above 0.25 mm thick plate is heat treated for 200'C110 minutes, which corresponds to baking painting, and then riveted and then rolled and bonded to a can body made of 3004 alloy that has undergone DI processing to strengthen the can body. I looked into it. At the same time, the yield strength of the blank plate after the above-mentioned heat treatment (baking) was also investigated. The rivet formability was determined by checking the presence of cracks and necking by protruding the rivet attachment part and performing rivet joints at a stroke speed of 150 spa+. These results are shown in Table 2.

As is clear from Table 2, all of the aluminum alloys of the present invention have good riveting formability, have significantly higher compressive strength than conventional alloys, and have a blank yield strength of about 1% higher than conventional alloys after baking. It can be seen that the strength is .5 times stronger.

[Example 2] An alloy ingot with a composition of Nα2 shown in Table 1 (the manufacturing method is Example 1)
) was hot rolled into a 3IIIO plate, and then 0
．． Cold rolled to 8am, solution treated, final plate thickness 0.2
The specimens were cold rolled to a temperature of 5.5 mm, subjected to aging treatment or not, and subjected to baking treatment at 200'C for 10 minutes to measure rivet forming and compressive strength. For the pressure test, the can joined to the can body is filled with nitrogen gas.
The pressure until the bottom of the can buckled was expressed as the filling gas pressure. These results are shown in Table 3.

As is clear from Table 3, according to the manufacturing method of the present invention,
It can be seen that the rivet formability is superior to that of the comparative example, and the pressure resistance strength is also significantly higher.

[Effects] As explained above, according to the present invention, an aluminum plate for cans having excellent formability and strength can be obtained, which exhibits remarkable effects in industry.

Claims (3)

[Claims] (1) Mg3-6wt%, Cu0.6-1.5wt%,
Si0.05~0.7wt%, Mn0.05~1.0w
t%, Fe0.1-0.7wt% and Cr0.01
~0.3wt%, Zr0.05~0.5wt%, Ti0
．． 005-0.3wt%, B0.0001-0.003
An aluminum alloy plate for cans, which contains one or more of wt% and the remainder is unavoidably contained impurities and Al. (2) Mg3-6wt%, Cu0.6-1.5wt%,
Si0.05~0.7wt%, Mn0.05~1.0w
t%, Fe0.1-0.7wt% and Cr0.01
~0.3wt%, Zr0.05~0.5wt%, Ti0
．． 005-0.3wt%, B0.0001-0.003
After hot rolling or cold rolling, an alloy consisting of Al and impurities containing at least one of wt% and the remainder unavoidably contained is heated to 400 to 500 ° C. for 2 seconds to 120 °C.
1. A method for producing an aluminum alloy plate for cans, which comprises holding the aluminum alloy plate for cans for a few minutes, cooling it to room temperature at a rate of 10° C./hr or more, and cold rolling it to the final thickness. (3) Mg3-6wt%, Cu0.6-1.5wt%,
Si0.05~0.7wt%, Mn0.05~1.0w
t%, Fe0.1-0.7wt% and Cr0.01
~0.3wt%, Zr0.05~0.5wt%, Ti0
．． 005-0.3wt%, B0.0001-0.003
After hot rolling or cold rolling, an alloy consisting of Al and impurities containing at least one of wt% and the remainder unavoidably contained is heated to 400 to 500 ° C. for 2 seconds to 120 °C.
1. A method for manufacturing an aluminum alloy plate for cans, which comprises holding the aluminum alloy plate for a few minutes, cooling it to room temperature at a rate of 10°C/hr or more, cold-rolling it to a final thickness, and then aging it at a temperature of 100 to 250°C.