JPS6022054B2 - High-strength Al alloy thin plate with excellent formability and corrosion resistance, and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-strength A-alloy board with excellent formability and corrosion resistance, and a method for producing the same.

In the manufacture of retainers, heat exchanger fins, caps, food cans, and the like, thin sheets such as soft pure A material typified by JIS AI 200 and A-alloy material are used.

In recent years, in order to reduce the weight and cost of these products, consideration has been given to using thinner sheets in the manufacture of these products. Increasingly, moldability, corrosion resistance, and strength are required for stretch molding, drawing molding, hole expansion molding, etc.

In other words, for the production of plate fin type fins for secondary vessels, for example heat exchangers, GIS/AI2 with a plate thickness of 0.13 to 0.2 mm and a tensile strength of about 9012 kg/mau is used.
European-quality pure A-type materials such as 00 or Japanese materials were used, but in recent years, a thin sheet processing technology called the drawless method has been developed, which combines stretch forming and iron forming. Since it has become possible to form a thin plate with a thickness of about 0.1, in order to reduce the cost of the fin, the fin can be formed using a thin plate with a thickness of about 0.10 to 0.12. Manufacturing is now being considered. but,
When using the above-mentioned thin plate to manufacture the above-mentioned fins, it is required to have high strength due to problems such as handling and adhesion between the tube and the fin, and in addition, in order to extend the life of the fin, it is required to have high strength. It is also required to be excellent.

In other words, a thin plate that can be formed by the above-mentioned drawless method must have a thickness of 0.115 or less, a tensile strength of 16k9/hiro or more, an elongation of 5% or more, and an Erichsen value of 5 or more. Therefore, it is extremely difficult to mold the above-mentioned soft pure A-layer material that does not have the above-mentioned characteristics. Therefore, from the above-mentioned viewpoint, the present inventors conducted research to develop an A-type alloy thin plate that has high strength and excellent formability that can be formed by the drawless method, and also has excellent corrosion resistance. As a result, M town: 0.1 to 0.6% Zn: 0.01 to 0.15% Y: 0.0005 to 0.02%, and Cu: 0.01 to 0.1% Fe: 0.1 to 0.5% Mg: 0.01 to less than 0.3% Ti: 0.005 to 0.1% Contains one or more of the following, and the remainder is unavoidable as A. After hot-rolling an A-alloy mirror block having a composition consisting of impurities (the above weight %) under normal conditions to make a hot-rolled sheet,
This is subjected to primary cold rolling at a rolling rate of 40% higher to form a cold rolled sheet, and then the cold rolled sheet is heated at a heating rate of 500 qo/min or higher at a heating rate of 50 qo/min or more from room temperature to the cold rolled sheet.
After rapid heating to a temperature in the range of 0 to 600 ° C., a high temperature short-time intermediate annealing is performed, which consists of immediately cooling to room temperature at a cooling rate of 500 q0 / min or more without heating and holding, and then the above-mentioned 60-95 for intermediate sintered anchor plate material
A thin plate with the final thickness is formed by performing secondary cold rolling at a rolling rate of 50%, and finally, the thin plate is subjected to heat-holding tempering at a temperature within the range of 200 to 350°C. It was discovered that the A-alloy thin plate produced by this method has high strength, which allows thin plate forming processing by the drawless method, excellent formability, and excellent corrosion resistance.

This invention was made based on the above findings, and the reason why the component composition range and manufacturing conditions were limited as described above will be explained below.

Chest Component composition range {a) Mn The Mn component is used as a solid solution in the base material to increase the recrystallization temperature of the A. It has the effect of improving sex, but
If the content is less than 0.1%, the desired effect cannot be obtained, while if the content exceeds 0.6%, coarse compounds will precipitate and the formability will deteriorate.
Its content was determined to be 0.1 to 0.6%.

[b} Zr and Y In the Zr and Y components, the recrystallization temperature of the A〆 alloy thin plate is further increased in a state where both of these components coexist.
This has the effect of improving the strength, and furthermore, this effect of increasing the recrystallization temperature makes the dawn anchor softening curve of the A-alloy thin plate gentler, which has the effect of making it easier to carry out the final process of tempered sintered anchor. However, if the content is less than 0.01% Zr and less than 0.0005% Y, the desired effect cannot be obtained; on the other hand, if the content is less than 0.15% Zr and 0.02% Y Even if the Zr content exceeds 0.01 to 0.1%, the effect of further improving the above effect cannot be obtained.
5%, Y: 0.0005 to 0.02%.

[c) C↓ Fe, Mg, and Ti These components have the uniform effect of solidifying into the base material and improving the strength and corrosion resistance of the thin slope, and Ti has the effect of refining the cast structure. However, the content is Cu: 0.0
When the content is 1%, Fe: less than 0.1%, Mg: less than 0.01%, and Ti: 0.005%, the desired strength improvement effect cannot be obtained, while Cu: 0.1%, respectively. , Fe:
If the content exceeds 0.5%, Ti: 0.1%, and Mg content exceeds 0.3%, the formability of the thin plate will deteriorate. , respectively Cu: 0.01-0.1%, Fe+0.1-0.
5%, Mg: 0.01-0.3%, and Ti: 0
．． 0.005 to 0.1%.

Wind Unavoidable impurities A of this invention and the alloy thin plate contain Si, as unavoidable impurities.
It contains Ni, Zn, etc., but especially in the Sj component, if the content exceeds 0.2%, it will have a negative effect on the properties of the A-alloy thin plate. It is desirable to limit the content to only a limited amount.

{B- Manufacturing conditions [a' Rolling rate of primary cross-rolling In order to impart the desired fine crystal structure to the intermediate sintered anchor plate material, primary cold rolling at a rolling rate of 40% or more is necessary. be.

'b} Intermediate annealing conditions Generally, when producing A-alloy thin plate containing Mn component,
Since the Mn component has the effect of coarsening crystal grains and deteriorating formability, current efforts are being made to make the crystal grains finer by taking heat treatment conditions and rolling conditions into consideration.

On the other hand, in the invention of (1), by using a Rentsugi sintering furnace and performing intermediate annealing at a rapid high temperature for a short time, coarsening of crystal grains caused by the Mn component is suppressed, and rather, the crystal grains are significantly refined, This ensures high strength and excellent formability. Therefore, the heating rate is 50℃/
If the heating temperature is less than 600 qo, crystal grains will grow and it will not be possible to obtain the desired fine crystal structure. If the cooling rate exceeds 500°C/min, the effect of primary cold rolling will be lost, making it impossible to secure a fine crystal structure, and will cause difficulties in the operation of the continuous dawn anchor furnace. If the heating rate is less than 500 qo/min, it will not be possible to exhibit the desired treatment effect and crystal grains will grow.
Heating rate: 500-60000, cooling rate: 500oo
/min or more in order to refine the crystal grains.

In addition, in the above-mentioned intermediate anchor, since the crystal grains will become coarse if maintained at the above-mentioned heating temperature, it is necessary to immediately cool the crystal grains at the above-mentioned cooling rate after heating to the above-mentioned heating temperature. As a result, it becomes possible to achieve high strength and excellent formability.

{c' Rolling rate of secondary cold rolling If the rolling rate is 60%, it will not be possible to secure the specified high strength, while if the rolling rate exceeds 95%, the formability will deteriorate. Therefore, the rolling rate is 60~
It was set at 95%.

{d} Heating temperature of the adjusting anchor: If the temperature is less than 20,000, the desired excellent formability cannot be secured; on the other hand, if the heating temperature is 350,
If it exceeds 0, the strength of the thin plate will decrease significantly, so
The heating temperature was set at 200 to 350 qo.

Next, the present invention will be specifically explained with reference to Examples.

Example A alloy ingot having the composition shown in Table 1 was produced by the usual melting method and casting method, and then hot-rolled to form a hot-rolled plate with a thickness of 5 skin. Then, this hot-rolled sheet was subjected to primary cold rolling, continuous cold rolling using a continuous racing anchor furnace, secondary cold rolling, and temper rolling under the same conditions shown in Table 1. As a result, Invention A-finished alloy thin plates 1 to 26 and Comparative A-finished alloy thin plates 1 to 9, each having a thickness of 0.1, were manufactured.

In addition, Comparative A thin alloy sheets 1 to 9 were all manufactured under conditions in which any of the component compositions and manufacturing conditions were outside the scope of the present invention (those marked with * in Table 1). In particular, comparative A-alloy thin plate 9 was produced according to a conventional method using a conventional A-alloy ingot and performing intermediate annealing by batch annealing instead of using a Rentsugi hammer furnace.

Next, the resulting thin alloy sheets 1 to 26 of the present invention A
And Comparative A, tensile strength of alloy thin plates 1 to 9,
Elongation and tensile strength: Measure the Eriksen value under the conditions of 15k9/mau, and use a Dolores fin die to apply it to a willow fin. Processed, observed its fin workability, and further
A salt water spray test was conducted for 1 day to measure the corrosion weight loss (converted to a year) and to observe the occurrence of pitting. These results are summarized in Table 2. From the results shown in Table 2, all of the thin alloy sheets 1 to 26 of the present invention A have a tensile strength of 16, which is required for forming by the drawless method, for example.
K9/pine or higher, elongation: 5% or higher, and Eriksen value:
Comparison A and alloy thin sheets 1 to 1 have excellent properties of 5 or more, as well as excellent formability and corrosion resistance, but any of the component composition and manufacturing conditions are out of the scope of the present invention. No. 9 is inferior in at least one of the above properties, formability, and corrosion resistance, and in particular, Comparative A. alloy thin sheet No. 9, which corresponds to the conventional A.
It is clear that the A alloy thin plates 1 to 26 of the present invention have superior properties compared to the above.

Claims (1)

[Claims] 1 Contains Mn: 0.6%, Zr: 0.01-0.15%, Y: 0.0005-0.02%, and further contains Cu: 0.01-0.1% Fe. : 0.1 to 0.5% Mg: 0.01 to less than 0.3% Ti: 0.005 to 0.1% Contains one or more of the following, and the rest is Al and inevitable impurities. A high-strength Al alloy thin sheet with excellent formability and corrosion resistance, characterized by having the following composition (the above weight %): 2 Contains Mn: 0.1-0.6% Zr: 0.01-0.15% Y: 0.0005-0.02%, and further contains Cu: 0.01-0.1% Fe: 0 .1 to 0.5% Mg: 0.01 to less than 0.3% Ti: 0.005 to 0.1% A composition containing one or more of the following, with the remainder consisting of Al and inevitable impurities. (wt%) is hot-rolled under normal conditions to form a hot-rolled plate, and then subjected to primary cold rolling at a rolling reduction of 40% or more to form a cold-rolled plate. Then, the cold-rolled sheet was heated to 50°C from room temperature in a continuous heat treatment furnace at a thermal rate of 500°C/min or more.
After rapid heating to a temperature within the range of 0 to 600°C, a high-temperature, short-time intermediate annealing is performed, which consists of immediately cooling to room temperature at a cooling rate of 500°C/min or more without holding the heat, and subsequently, 60 to 95 for the above intermediate annealing plate material.
% elongation to form a thin plate with the final thickness, and finally, the thin plate is subjected to temper annealing at a temperature within the range of 200 to 350°C. A method for producing a high-strength Al alloy thin plate with excellent formability and corrosion resistance.