JPS61288056A - Manufacture of aluminum alloy sheet for deep drawing - Google Patents

Abstract

PURPOSE:To obtain the titled sheet having particularly superior formability as well as strength equivalent to that of H19 materials by carrying out solution heat treatment under specific conditions after hot and cold rollings and then final cold rolling at a prescribed draft in manufacturing a hard sheet out of an Al-Mn-Mg-type Al alloy ingot having a specific composition. CONSTITUTION:The Al alloy ingot consisting of 0.1-1% Si, 0.2-2% Mg, 0.2-2% Mn, 0.1-0.3% Cu 0.005-0.2% Zn and the balance Al is homogenized and then subjected to hot rolling and cold rolling to be formed into sheets, which are subjected, as process annealing, to solution heat treatment constituted of holding at 500-600 deg.C for 5sec-5min and successive quenching, followed by final cold rolling at 30-70% draft.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the production of AI-Mn-MQ aluminum alloy sheets with excellent deep drawability, and particularly to the application of coating at any forming stage, regardless of whether before or after product forming. The present invention relates to the production of aluminum alloy hard plates with excellent drawability and strength for aluminum alloy plates to be subjected to baking treatment.

Conventional technology Conventionally, aluminum alloy plates for deep drawing are usually
14, rolling reduction ratio of finish cold rolling 30-50%
A semi-rigid plate, a semi-soft plate indicated by H24, or a fully annealed plate indicated by 0 have been used because they have excellent deep drawability.

In recent years, with advances in product forming technology, hard plates obtained by finish cold rolling with a rolling reduction of more than 50% have come to be used for deep drawing. This is largely due to the economic benefits of using sheets made from higher strength alloy materials.

The AI-Mn-Mg aluminum alloy represented by A 3004 is known to have relatively good strength and formability when used in hard plates, and these hard plates can be deep drawn for cans, barrels, etc. It is used in many products.

Such hard plates are produced by a process consisting of hot rolling, cold rolling, intermediate annealing, and final cold rolling, with intermediate annealing at 350°C.
The product is colored at ~450°C for 0.5~3 hours, and the final cold rolling reduction is 70~85%. Hard plates manufactured in this manner are often subjected to paint baking treatment before or after the process of forming products such as cans.

Problems to be Solved In the conventional technology, as mentioned above, from the viewpoint of obtaining a thin plate with high strength, the finishing cold opening rolling reduction ratio is 80 to 90%.
It is preferable to use a so-called H2O material (super hard plate) obtained by increasing the hardness. However, if the plate is made harder (strengthened) by increasing the reduction rate during finish cold rolling, the formability will also decrease.
There was a problem in that it was unfavorable from the point of view of moldability.

The present invention has strength equivalent to H2O material, and
It is possible to produce an aluminum alloy plate for deep drawing with much better formability. The purpose of this invention is to provide a manufacturing method thereof.

Means for Solving the Problems In order to achieve the above object, the present invention is configured as follows.

That is, the present invention provides a method for producing an aluminum alloy plate for deep drawing, in which Si: 0.1 to 1%, Mg:
0.2-2%, Mn: 0.2-2%, Cu: 0.
1 to 0.3%, Zn2 0.005 to 0.2%,
After homogenizing an aluminum alloy ingot in which the remainder is substantially Al, it is hot-rolled and cold-rolled into a plate, which is then held at 500°C to 600°C for 5 seconds to 5 minutes and then rapidly cooled. After solution treatment consisting of
~70% final cold rolling is performed.

Hereinafter, the configuration of the present invention will be explained in detail.

Each alloy component is added to increase the strength of aluminum, but the components that particularly dominate the strength are MQ,
Mn and Si. Mg and 3i increase the strength by forming a fine compound called MIl12Si.

Cu and Zn increase strength by forming a Mo-Cu-Zn compound and contribute to improving moldability.

Mn forms fine precipitates when rapidly cooled from high temperatures and tempered, but this does not affect the strength of the alloy components.

If each of these components is less than the lower limit, the strength will be insufficient, and if it exceeds the upper limit, coarse compounds will be formed, reducing moldability, and it will become too hard, causing molding defects, which is not desirable. . Furthermore, zn is useful for increasing the strength of the board after the coating is baked.

In the conventional production of hard plates or ultra-hard plates, the final cold rolling is performed at a rolling reduction of 70 to 85%.

However, the hard plate manufactured by this method has a large reduction amount in the final cold rolling, so although its strength is high, its deep drawability is not good.

In contrast, according to the present invention, by holding the temperature at 500°C to 600°C for 5 seconds to 5 minutes and then rapidly cooling it, so-called solution treatment is performed as intermediate annealing. , it has become possible to obtain strength comparable to that of a hard plate by reducing the amount of reduction exceeding 70% of the conventional strength without impairing deep drawability.

In addition, the temperature increase rate to the annealing temperature should be 5°C/sec or more, and 15
It is desirable that the cooling rate to below 0°C be 5°C/sec or more. If the annealing temperature is lower than 500°C and the holding time is shorter than 5 seconds, the required strength cannot be obtained. On the other hand, if the temperature is higher than 600°C, the plate will melt and the strength obtained will not change even if the plate is held for longer than 5 minutes, which is economically disadvantageous.

If the reduction rate in the final cold rolling is lower than 30%, it will not be possible to obtain the strength equivalent to that of a conventional hard plate. becomes large, which is not desirable. The optimal range is 40-60%.

According to the present invention, an aluminum alloy intermediate plate before final rolling is solution-treated and then finally cold-rolled to obtain a hard plate material. , if the paint baking at 150 to 220°C is treated, this treatment works in conjunction with the solution treatment according to the present invention, and the similar baking is equivalent to or higher than that of the conventional hard plate treated. strength can be obtained. In other words, since the amount of reduction in the final cold rolling is small, the as-rolled sheet is relatively soft and has good formability, and the subsequent baking reduces the strength when subjected to treatment, or The treatment causes age hardening and increases strength. As a result, the strength of the paint baking is equal to or higher than that of the conventional 819 board which has been treated. With conventional hard boards, the strength of paint baking decreases due to treatment.

LL Example 1 After homogenizing the alloy ingots having the above components at 580° C. Subsequently, each hot rolled sheet was subjected to the steps of cold rolling, intermediate annealing, and final cold rolling under the conditions shown in Table 1 below to obtain a finished sheet of 0.41111.

毫 Prior Art (The same applies to the table below) Note that the heating rate at 550° x 3 G seconds during intermediate annealing was a minimum of 8°C/second, and the cooling rate was a minimum of 9°C/second. Each finished board thus obtained was subjected to a heat treatment at 205° C. for 10 minutes, which corresponds to the paint baking treatment. The properties of the finished board subjected to this heat treatment and the finished board before this treatment are shown in Table 2.

Table 2 ◇ ・5 i ch, z (yield strength), σa (tensile strength): Measured with JISS No. piece he (ear ratio) Ni blank 55 mφ, punch diameter 3
OR (limit drawing ratio) measured on a cup drawn with 3WIlφ (tip R = 2 m): Drawing with punch diameter 331111φ (tip R-211111) As is clear from Table 2,
As for finished plates as manufactured, those according to the present invention have almost the same strength as conventional hard plates (No. 7, No. 8, No. 8), and deep drawability is superior to hard to ultra-hard sheets (No. 8).
, 6 to N0.8>, and the selvage rate is also significantly lower.

On the other hand, a finished board that has undergone heat treatment has excellent shaping and strength that is superior to conventional hard boards and equal to or greater than ultra-hard boards. The ear rate is significantly lower than these.

Example 2 Alloy ingots having the above components were mixed with No. 61 to No. 1 of Example 1.
0.4 by the process under the same conditions, respectively.
It was made into a finished board with a thickness of 111 mm. Then, similar heat treatment was performed. Table 3 shows the properties of the finished board before and after heat treatment.

The products in Table 3 have a strength equal to or higher than that of the prior art as manufactured, a small selvage ratio in the strength warp, and a higher deep drawability. On the other hand, when heat treated, the strength is higher than the ultra-hard plates and hard plates made by conventional techniques, the deep drawability is further improved, and the selvage rate is significantly lower than the strength.

Example 3 Alloy ingots having the above components were used as No. 1 to No. 0.1 of Example 1.
0.4- by the process under the same conditions, respectively.
A one-thick finish plate was used. Then, similar heat treatment was performed. Figure 4 shows the characteristics of the finished board before and after heat treatment.

Table 4 As is clear from Table 4, the finished plate obtained according to the present invention, even as manufactured, is the ultra-hard plate (N O,
With almost the same strength as a hard plate (No. 6”) or a hard plate (No. 7”),
It has a small selvage ratio and good deep drawability. On the other hand, when subjected to heat treatment, it has higher strength than an ultra-hard board or a hard board, and also has a smaller selvage ratio and high deep drawability. Also, No. 1, No. 2”, No. 5 in the same table.
As can be seen from ``, even if the intermediate annealing conditions satisfy those of the present invention, if the reduction ratio in the final cold rolling exceeds 70%, the formability decreases both before and after the heat treatment, and If the selvage ratio is large and the rolling reduction ratio is less than 30%, sufficient strength cannot be obtained.

Example 4 The alloy ingots having the above components were each homogenized at 580°C x 10 hours, then hot rolled at 550°C to form a plate with a thickness of 41. Subsequently, it was cold rolled to a thickness of 0.80+e-. Intermediate annealing was performed under the conditions shown in Table 5 below, and final cold rolling was performed with a reduction of 50% to give a thickness of 0.40+em. Thereafter, heat treatment was performed at 205° C. for 10 minutes.

Table 6 shows the properties of the finished plate thus obtained before and after heat treatment.

Table 6 Table 6 shows that the finished board according to the present invention, as manufactured, has a small selvage on average and good formability, and the paint baking shows high strength after treatment. With,
It has been shown that good moldability can be obtained. On the other hand, as in the comparative example, if the intermediate annealing temperature is low or if the temperature is not rapidly cooled from the annealing temperature, the strength of the paint bake will decrease significantly after the treatment, and the paint will have sufficient strength and high formability. It becomes clear that the object of the invention of producing a drawing plate is not achieved.

Effect of the invention The effects obtained by the present invention are as follows.

(1) With a final cold rolling reduction of 30 to 70%, it has strength equivalent to conventional hard plates or ultra-hard plates with a higher rolling reduction, and has good forming properties that are not found in these hard and hard plates. It is possible to obtain a deep-drawing plate with high properties and a small selvage ratio.

This effect is more noticeable on boards that have been treated with paint baking.

(2) In the vI baking process, the thermal energy in the process can be effectively used as an aging process. In the prior art, the strength of the paint bake is reduced by the treatment.

■By performing cold rolling before intermediate annealing, the plate to be annealed can be made to any thickness, so hot rolling can be done in accordance with the required thickness of the final cold rolled plate. There is no need to change the rolling reduction rate.

Claims (1)

[Claims] Si: 0.1-1%, Mg: 0.2-2%, Mn: 0.
2-2%, Cu: 0.1-0.3%, Zn: 0.005
After homogenizing an aluminum alloy ingot containing ~0.2% and the remainder being substantially Al, it is hot rolled and cold rolled into a plate, and then this plate is heated to 500°C to 600°C. A method for producing an aluminum alloy plate for deep drawing, which comprises performing a solution treatment consisting of holding for 5 seconds to 5 minutes and then rapidly cooling, followed by final cold rolling at a reduction rate of 30 to 70%.