JP3157068B2 - Manufacturing method of aluminum alloy sheet for forming - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Al-Mg-Si used for a member for forming a plate material such as an automobile body sheet.
The present invention relates to a method for producing a system-based aluminum alloy sheet material, which improves strength and formability.

[0002]

2. Description of the Related Art Recently, in order to reduce the weight of an automobile body,
Studies have been made on the application of Al-Mg-Si-based aluminum alloys to automobile body sheets and the like. Conventionally, A
The l-Mg-Si based aluminum alloy is formed in a naturally aged (T4) state after the solution treatment, and is subjected to age hardening (baking hardening: bake hardening) during coating and baking (baking) heating.
den) can be obtained, and its use in automobile bodies and the like has been considered. A problem that arises when a body sheet or the like of an automobile body currently manufactured from a steel sheet is replaced with an aluminum alloy plate material is mainly low formability. For this reason, even better formability is required for Al-Mg-Si based alloys. On the other hand, although the strength of aluminum plates is originally inferior to steel plates, more recently, in order to reduce costs, aluminum alloys that can be coated and baked (age hardened) at a low temperature for a short time to obtain high strength have been developed. Is desired.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and as a result of various studies, it has been found that Al can improve the strength and formability of an Al-Mg-Si based aluminum alloy.
-A method for producing Mg-Si based aluminum has been developed.

[0004]

Means for Solving the Problems A method of manufacturing an aluminum alloy sheet for forming according to the present invention is constituted as follows to solve the above-mentioned problems. That is, the method for producing a forming aluminum alloy sheet material according to claim 1 includes the steps of: 0.3 to 1.7 wt% of Si and 0.01 to 1.2 Cu.
wt%, Mn0.01-1.1 wt%, Mg0.4-
1.4 wt%, Fe 1.0 wt% or less, the balance Al
And an aluminum alloy ingot consisting of unavoidable impurities are subjected to a hot rolling and a cold rolling.
Solution treatment in a temperature range of 0 ° C. or more and below the solidus line, adjustment of the quenching process and 0.5 to 5 at a temperature of 100 to 150 ° C.
It is characterized in that the low-temperature heat treatment is performed for a long time to control the volume ratio of the age-hardened intermetallic compound to 0.01 to 0.1%. The method for manufacturing an aluminum alloy sheet according to claim 2 of the present invention is intended to solve the above-described problems.
0.3-1.7 wt% of Si, 0.01-1.2 wt% of Cu
%, Mn 0.01 to 1.1 wt%, Mg 0.4 to 1.4
wt%, Fe1.0 wt% or less.
04-0.4 wt%, Zn 0.25 wt% or less, Zr
Any one of 0.4 wt% or less and Ti 0.2 wt% or less
After homogenizing the aluminum alloy ingot containing the seed or two or more, and the balance of Al and unavoidable impurities, hot rolling and cold rolling are performed, and then the solution is heated at a temperature in the range of 450 ° C or higher and the solidus temperature or lower. And quenching process adjustment and 1
A low-temperature heat treatment at a temperature of 00 to 150 ° C. for 0.5 to 5 hours is performed to reduce the volume ratio of the age-hardened intermetallic compound to 0.01 to
It is characterized in that it is controlled to 0.1%.

[0005]

The Al-Mg-Si based alloy targeted in the present invention is an alloy corresponding to the above composition range, for example, JIS. 6301,6004,6005,6105,6
JIS such as 151, 6061, 6066, 6070
Applicable to 6000 series alloys. The Al-Mg-Si based aluminum alloy is an age hardening type alloy, and the strength of the alloy is increased by generating a hardened precipitation phase during aging treatment. The aging precipitation process of the Al-Mg-Si-based aluminum alloy is as follows. Supersaturated solid solution → G. P. Zone → Intermediate phase → Stable phase After solution and quenching alloy, aging at room temperature (T4 treatment)
Then, G. and Si bonded to the excess vacancies quenched with the solute atoms Mg and Si. P. Zones are created and the strength of the alloy is slightly higher. Thereafter, by painting and baking (artificial aging), an intermediate phase, which is a hardened precipitation phase (intermetallic compound) that contributes most to the strength of the alloy, is precipitated, and the strength of the alloy to be a product is obtained. . However, during natural aging, most of the vacancies are G. P. Since it is included in the zone, the precipitation of the intermediate phase is hindered even after artificial aging, and the highest strength of the alloy cannot be obtained. When a naturally aged alloy is formed, G.I. P. Since the zone is consistent with the matrix (Al), it is easily cut into dislocations during deformation, and finally stress concentrates on the grain boundaries and the formability of the alloy decreases. Based on the above findings, the manufacturing method of the present invention was developed for the purpose of improving the strength and formability of the alloy using an industrially easy-to-operate manufacturing method for Al-Mg-Si-based aluminum alloys. is there.

In the present invention, the composition of the target alloy is limited as described above for the following reasons. Si precipitates Mg ₂ Si together with Mg during painting and baking to improve the strength. The content is 0.3 to 1.7
If the content is less than 0.3 wt%, the effect is small, and if it exceeds 1.7 wt%, the formability after the solution treatment is reduced. Mg forms a solid solution in the matrix after the solution treatment and contributes to the improvement of the moldability. At the time of painting and baking, Mg ₂ Si is precipitated together with Si to improve the strength. The reason that the amount is set to 0.4 to 1.4 wt% is that if the amount is less than 0.4 wt%, the strength improvement is small,
If the content exceeds 1.4% by weight, the formability after the solution treatment is reduced.

[0007] Cu is applied to G. P. zone,
Precipitates θ ′, S phase, etc. to improve strength. The reason for setting the amount to 0.01 to 1.2 wt% is that if the content is less than 0.01 wt%, the strength improvement is small, and if it exceeds 1.2 wt%, the corrosion resistance is reduced. Mn and Cr reduce the size of crystal grains and improve matrix strength. Set the amount to 0.
The reason for setting the content to 01 to 1.1 wt% and 0.04 to 0.4 wt% is that if the content is less than the lower limit, the effect is small, and if the content exceeds the upper limit, the moldability after the solution treatment is reduced. Zn has an effect of improving strength, and Zr, T
i has the effect of refining the structure, but Zn 0.25 wt
%, Zr 0.4 wt%, and Ti 0.2 wt%, the moldability decreases. Fe is usually contained as an impurity of Al, but if it is 1.0% by weight or less, the effect of the production method of the present invention is not hindered. In addition, impurities other than the above,
If the content is 0.5 wt% or less, the effect of the production method of the present invention is not hindered.

[0008] In the production method of the present invention, the above-mentioned Al-Mg-Si-based aluminum alloy is melt-cast, homogenized, and rolled by a usual method, and then subjected to a temperature range from 450 ° C to the solidus temperature. After the solution treatment, the aging process is adjusted and the low-temperature heat treatment is performed to reduce the age-hardened intermetallic compound (precipitate of the intermediate phase of Mg ₂ Si) by 0.01% by volume.
~ 0.1% by precipitation, strength,
It improves the formability. The reason why the solution treatment temperature is set at 450 ° C. or more and the solidus temperature or less is that, outside this temperature range, Si and Mg do not sufficiently form a solid solution in the matrix, and the formability decreases. As for the adjustment of the quenching process, after the solution treatment, water quenching or a predetermined temperature, for example, 100
By quenching to ~ 150 ° C, precipitation of coarse precipitates can be prevented. As the low-temperature heat treatment, it is desirable to perform a heat treatment at a temperature of 100 to 150 ° C. for 0.5 to 5 hours. Outside the above-mentioned temperature range and outside the time period, the age-hardened intermetallic compound (precipitate of the intermediate phase of Mg ₂ Si) cannot be precipitated to have a volume ratio of 0.01 to 0.1%. The desired strength and moldability cannot be obtained.

[0009] The aluminum alloy sheet produced by the method of the present invention significantly improves the formability such as elongation, Erichsen value and LDR. The baking process performed after molding is subjected, 0.0 prior to baking
Age-hardened intermetallic present as 1-0.1% volume fraction
By growing the compound, the mechanical strength such as the tensile strength and the proof stress is remarkably improved as compared to before the baking treatment.

[0010]

An embodiment of the present invention will be described below.
An aluminum alloy having the chemical composition (wt%) shown in Table 1 is melt-cast by a usual method, subjected to a predetermined homogenization treatment, hot-rolled at 400 ° C., and then cold-rolled to obtain a 1 mm-thick plate. did. This plate material was subjected to a solution treatment and a heat treatment shown in Table 2. That is, as an example of the production method of the present invention, after solution treatment at 560 ° C. × 1 hour, water quenching is performed, and immediately 100 ° C. × 5 hours, 120 ° C. × 1 hour, 150 ° C. ×
Heat treatment for 0.5 hour, or quenching in a heat treatment furnace at 100 ° C., 120 ° C., 150 ° C. directly after solution treatment under the same conditions and heat treatment at those temperatures for 0.5 to 5 hours, An intermetallic compound with a volume fraction of 体積 0.1% was obtained. Finally, a baking treatment (180 ° C x
1 hour). For comparison, first, (1) solution treatment according to a conventional method, quenching to room temperature, T4 treatment, and then baking treatment (180 ° C. × 1 hour), and (2) 0.01 to 0 0.1% volume ratio of the intermetallic compound is not obtained, that is, immediately after the solution treatment, 60 ° C. × 10 hours, 80 ° C. × 8 hours, 180 ° C. ×
After heat treatment for 20 minutes at 200 ° C. × 10 minutes, a sample subjected to a baking treatment (180 ° C. × 1 hour) was used as a sample. For these plates, tensile tests, Erichsen overhang tests,
A critical depth drawing (LDR) test was performed. Table 3 shows the results.
The results are shown in Tables 4, 5, 6, 7, and 8.

The tensile test was carried out using a JIS No. 5 tensile test piece, and the Erichsen overhang test was conducted according to JIS Z2247A.
The overhang height was measured by the method. In the critical depth drawing (LDR) test, a blank coated with lubricating oil with a punch having a diameter of 33 mm was deep drawn, and a value obtained by dividing the maximum blank diameter that did not break by the punch diameter was obtained. The volume ratio of the age-hardened intermetallic compound was determined by known image processing.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[0015]

[Table 4]

[0016]

[Table 5]

[0017]

[Table 6]

[0018]

[Table 7]

[0019]

[Table 8]

As is clear from Tables 1 to 8, all of No. 1 to No. 12 according to the present invention have elongation, tensile strength,
It can be seen that various properties such as proof stress, Erichsen value and LDR are excellent. On the other hand, No. 13 and N
o.14 and No.15 to No.22 of the conditions deviating from the present invention
It can be seen that any one or all of the properties such as elongation, tensile strength, proof stress, Erichsen value, LDR and the like are remarkably lower than those according to the production method of the present invention. Tables 3 to 8
In the case of odd heat treatment before baking
The volume ratio of the intergeneric compound was measured.
In the case of an even heat treatment method, the effects of the present invention may not be neglected.
Therefore, the volume fraction of the intermetallic compound was not measured.

[0021]

As described above, according to the present invention, compared with Al-Si-Mg alloys manufactured by the conventional manufacturing method, the alloys are particularly excellent in elongation and improved in strength. It is the most suitable as a method for manufacturing a member, and has remarkable effects such as a large contribution to the improvement of the formability and strength of the material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int. Cl. ⁷ Identification symbol FI C22F 1/05 C22F 1/05 (56) References JP-A-4-160131 (JP, A) (58) Fields surveyed (Int. .Cl. ⁷ , DB name) C22F 1/00 C22C 21/00-21/18 C22F 1/05

Claims (2)

(57) [Claims] 1. Si 0.3-1.7 wt%, Cu 0.0
1-1.2 wt%, Mn0.01-1.1 wt%, Mg
Containing 0.4 to 1.4 wt% and Fe 1.0 wt% or less,
After homogenizing the aluminum alloy ingot consisting of the remaining Al and inevitable impurities, hot rolling and cold rolling are performed, and then solution treatment is performed at a temperature in the range of 450 ° C. or more and below the solidus line, and adjustment of the quenching process And at a temperature of 100-150 ° C
A method for producing an aluminum alloy sheet for forming, characterized in that a low-temperature heat treatment is performed for 0.5 to 5 hours to control the volume ratio of an age-hardened intermetallic compound to 0.01 to 0.1%. 2. 0.3 to 1.7 wt% of Si, 0.0 of Cu
1-1.2 wt%, Mn0.01-1.1 wt%, Mg
Containing 0.4 to 1.4 wt% and Fe 1.0 wt% or less,
Furthermore, Cr 0.04 to 0.4 wt%, Zn 0.25 wt
%, Zr 0.4 wt% or less, Ti 0.2 wt% or less, and after homogenizing an aluminum alloy ingot consisting of the balance of Al and inevitable impurities, hot rolling, cold rolling Cold rolling, then solution treatment in a temperature range of 450 ° C. or more and a solidus or less, and a quenching process adjustment and a low temperature heat treatment at a temperature of 100 to 150 ° C. for 0.5 to 5 hours. A method for producing an aluminum alloy sheet for forming, wherein the volume ratio of the age-hardened intermetallic compound is controlled to 0.01 to 0.1%.