JPS61199057A - Aluminum can for drink - Google Patents

Abstract

PURPOSE:To improve workability in the secondary working stage of the titled Al cans to be obtained and to reduce pinholes and flange cracking of cans, by using as a can stock an Mn-containing aluminum alloy which is provided with specific mechanical properties by prescribed heat treatment after drawing the ironing. CONSTITUTION:As the Al alloy for can stock, 'A3104-H19' containing 0.8-0.9% Mn is used, which is subjected to heat treatment in a washing and drying furnace at >=270 deg.C for 5-10min after drawing with ironing. The alloy which is reduced in tensile strength to 23-25kg/mm<2> and increased in elongation to 6.5-8% is used as can stock. In this way, the can stock after drawing with ironing is provided with ductility, so that workability in bulging and necking (the secondary working) is improved and the titled Al cans reduced in pinholes and flange cracking can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION ■Field of Industrial Application This invention relates to aluminum beverage cans, and more specifically, has good workability in bulging, necking, etc. performed after drawing and ironing (hereinafter referred to as DI) processing. ,
DI with less occurrence of pinholes and flange cracks
This invention relates to aluminum cans for beverages made of aluminum alloy for processing.

2. Prior Art Conventionally, Al--Mn-based aluminum alloys have been widely used as can materials for aluminum beverage cans manufactured by DI processing, bulge processing, necking processing, and the like. This Al-Mn-based aluminum alloy is D
It has mechanical strength suitable for I processing, and has tensile strength, yield strength, and elongation that can withstand DI processing, which is the next processing. In general, materials with high mechanical strength, high tensile strength, high yield strength, and high elongation have excellent workability as can materials, and can be effectively used to address the current trend toward thinner can walls. In DI processing, if the barring rate exceeds 45%,
Mechanical strength with a tensile strength of 20 kg/mm or more is required, and can materials that satisfy this strength include 5, for example, J I
SA 3004-HI3 has traditionally been used. This J
ISA 3004-H19 has a washing drying temperature of approximately 200
Mechanical properties after heat treatment at ℃ for 5 minutes are tensile strength 3
0-32 kg/mm.

It has an elongation of 3 to 4.5% and has mechanical properties that can sufficiently withstand DI pre-processing.

L KaL f, K 7! l(et al., J l5A300
4-4 (19 is DI pre-processing - next processing) bulge processing,
The self-lubricating properties and workability during necking processing (secondary processing) are poor, and pinholes and flange cracks occur in the can during secondary processing, with the occurrence rate being extremely high at 300 to 350 PPM. Generally speaking, when can stock has high tensile strength and yield strength, it tends to elongate less and become harder, so work hardening during pre-DI processing increases and residual stress remains in the can stock. This is considered to be the cause of pinholes and flange cracks during secondary processing. Therefore, a can material suitable for secondary processing needs to be a ductile material with little work hardening.

■Problems to be solved by the invention This invention was made by focusing on these conventional problems, and the can materials that have been used in the past can be converted to JISA300
By changing from 4-HI3 to A3104-HI3 and increasing the heat treatment temperature.

Bulge processing is performed by imparting ductility to the can material after DI processing.

The purpose of the present invention is to improve the workability of necking processing (secondary processing) and to provide an aluminum beverage can with fewer pinholes and flange cracks.

In order to achieve this object, the present invention provides an aluminum alloy for DI processing that is used as a can material in aluminum beverage cans that are manufactured by performing bulge processing, necking processing, etc. after DI processing. A3104-HI3 containing M n 0.8-0.9%.

After DI processing, the A3104-H19 was heat treated in a washing drying oven at 270°C or higher for 5 to 10 minutes to reduce the tensile strength in mechanical properties to 23 to 25 kg/mm and the elongation to 6.5 to 8%. The feature is that the can material is made from an increased amount of water.

It has a structure that has more than 0 action. The operation of this invention will be explained.

This invention uses A3104-HI3 as the can material.
This is because the work hardening in the pre-I processing was small, and the heat treatment temperature after the DI processing was raised to 270°C.

Although the tensile strength decreases, the elongation increases and the can material becomes ductile, improving workability in secondary processing.

1. This invention will be explained based on the following test examples. Table 1 below shows the differences in the main chemical components, excluding aluminum, between the conventional JIS A3004-HI3 and the can material 3104-HI3 according to the present invention.

Table ■ As is clear from Table 1, A3104-HI3 is J
The Mn (7) content is lower than that of ISA 3004-HI3, and this Mn content affects workability in secondary processing.

Furthermore, in this invention, after DI processing, A3104-HI3 is heat treated in a washing and drying oven to change its mechanical properties. Specifically, as a result of increasing the heat treatment temperature from the conventional heat treatment temperature of 200°C to 270°C, the tensile strength in mechanical properties was 26 to 28 kg/mrr? It decreased from 23 to 25 kg/mm2.

On the contrary, the elongation increased from 3-4.5% to 6.5-8%.

In addition, the toxin level also increased. The relationships between the heat treatment temperature after DI processing, tensile strength, elongation, and knee W value are shown in FIGS. 1, 2, and 3, respectively.

From this test result, it is clear that the can material becomes more ductile as the heat treatment temperature increases after DI processing, and this change in mechanical properties has a large effect on improving workability in secondary processing. . Furthermore, one crystal grain is also 270"
A change was observed between c and 280°C.

■Effects As explained below, according to this invention, since Mn is added, workability in secondary processing can be improved by reducing work hardening and increasing elongation, and the pinholes that occur can be reduced to IPPM or less. This has the effect of reducing flange leakage to 8 PPM or less. JISA300, the conventional can material
4-H19 and A3104-H1 of the can material according to this invention
A comparison of the pinhole occurrence rate and flange leakage occurrence rate under each condition of No. 9 is shown in Table 3, FIGS. 4 and 5.

A B CD E (sample) procedural amendment (method) % formula % 2. Title of the invention Aluminum beverage can for beverages 3. Relationship to the amendment case Patent applicant address 1-1o Kamiakaecho, Toyama City, Toyama Prefecture -1 June 25, 1985 6. Contents of the Amendment Details of the amendment as shown in the attached sheet [A brief explanation of 1 drawing in book l is added as follows.

[Brief explanation of drawings]

Figures 1 to 3 show can material A according to the present invention.
3104-HI3 is a graph showing mechanical properties,
Figure 1 is a graph showing the relationship between the tensile strength in the laddering direction (kg/n) and the heat treatment temperature ("C) after DI processing, Figure 2
The figure shows the relationship between the elongation (%) in the can wall edge direction and the heat treatment temperature (C) after DI processing. (”
It is a graph showing the relationship with C). Figures 4 and 5 are graphs comparing the effects of J[S^3004-1119, a conventional can material, and A3104-H19, a can material according to the present invention. Regarding the rate, JIS^3004-1119 samples A, B, and C
, D and sample E of 83104-H19, Figure 5 shows the flange leakage rate of J15A30.
04-Old 9 samples A, B, C, D and A3104-141
9 is a graph comparing sample E with sample E. ” he adds.

Claims (1)

[Claims] In an aluminum beverage can manufactured by performing bulge processing, necking processing, etc. after drawing and ironing, the aluminum alloy for drawing and ironing used as the can material contains 0.8 to 0.9% Mn. A3104-H19 containing A3104-H19 after drawing and ironing.
Cans are heat treated in a washing drying oven at 70°C or higher for 5 to 10 minutes to reduce the mechanical properties of tensile strength to 23 to 25 kg/mm^2 and increase elongation to 6.5 to 8%. An aluminum can for beverages characterized by the material.