JPH028342A - Aluminum alloy plate for two-piece wheel rim and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture the title alloy plate having high brightness by subjecting an Al alloy having the specific compsn. contg. Mg, Cu, Si, Fe, Ti, B and impurity elements to heating, hot rolling and finish annealing at specific temp. CONSTITUTION:An Al alloy ingot constituted of, by weight, 2.0 to 5.0% Mg, 0.05 to 0.15% Cu, <=0.10% Si, <0.10% Fe, 0.005 to 0.10% Ti, 0.0001 to 0.05% B, in which inevitable impurity elements are regulated to inevitably <=0.05% and total <=0.1% and the balance Al is heated to 450 to 550 deg.C and is thereafter subjected to hot rolling. The hot rolled plate, as it is, or subjected to cold rolling at need is thereafter subjected to finish annealing at 300 to 450 deg.C. The ratio of the crystalline grain size in the orthogonal direction to the crystal grain size in the direction of the plate thickness is then regulated to <=2.0. By this method, the Al alloy plate for a two-piece wheel rim having high brightness, having excellent brightness in the zone subjected to flashbutt welding and having little difference in its base metal and the weld zone can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides high brightness of the base material and flash butt welded area when anodized after chemical polishing, and there is almost no difference in brightness between the two. The present invention relates to a method of manufacturing an aluminum alloy plate for a two-piece wheel rim.

[Conventional technology]

Conventionally, JIS A was used as the rim material for two-piece wheels.
3052 alloy and JIS A3454 alloy are often used. This alloy cannot be said to be a high-quality bright wheel rim material because the anodizing treatment after chemical polishing does not give the base material sufficient brightness, and the flash butt welded area becomes cloudy and conspicuous.

[Problem that the invention seeks to solve]

The purpose of this invention is to overcome the drawbacks of the above-mentioned prior art and to develop an aluminum alloy plate for two-piece wheel rims, which has high brightness in the base metal and flash butt welded area, and has almost no difference in brightness between the two. shall be.

[Means for solving problems]

The present invention was developed as a result of the inventor's extensive research into improving the two-piece wheel rim chassis described above. We have developed an alloy plate that has improved uniformity during polishing and anodizing. Specifically, (1) Mg2.0-5.0% by weight;
Cu 0.05-0.15%, Si 0.10% or less, F
e less than 0.10%, Ti 0.005-0.10%, B
0.0001 to 0.05%, and other unavoidably contained impurity elements are each 0.05% or less and the total is 0.
．． 1% or less, the balance being A and Q, and the ratio of the crystal grain size in the direction perpendicular to the crystal grain size in the plate thickness direction is 2.0 or less. Board.

(2) By weight, Mg 2.0-5.0%, Cu 0.05
~0.15%, Si 0.10% or less, Fe less than 0.10%, Ti 0.005-0.10%, B 0.0001
~0.05%, and other unavoidably contained impurity elements are each 0.05% or less, and the total is 0.1% or less,
The aluminum alloy ingot consisting of the remaining parts A and Q was heated to 450°C.
A method for manufacturing an aluminum alloy plate for a two-piece wheel rim, which comprises heating at ~550°C, followed by hot rolling, and finish annealing either as is or after cold rolling at a temperature of 300°C to 450°C.

0 Reasons for limiting the chemical composition Mg: An essential element to provide strength to the product of the present invention. If it is less than 2.0%, sufficient strength cannot be obtained, and if it exceeds 5.0%, the strength is too high. Since it impairs moldability, it is set at 2.0 to 5.0%.

Cu: Has the effect of improving brightness during chemical polishing. 0
．． If it is less than 0.05%, there is almost no effect, and 0.15%
Cu is 0.05 to 0.15 because the color tone changes when it exceeds
% range.

Si: Combines with Mg to form an intermetallic compound called M g 2 Si, which impairs brightness during chemical polishing, so St is 0.
．． It is essential to keep it below 10%.

Fe: Combines with AIl to produce an Aρ-Fe(Mn)-based intermetallic compound, which impairs brightness during chemical polishing.

Therefore, it is essential to suppress Fe to less than 0.10%.

TiB: These elements are effective in refining the casting structure and improving weldability as in general aluminum alloys, and Ti is 0.005-0.10% and B is 0.0001-0.0001%.
The range is 0.05%. If each of these impurities is not 0.05% or less and the total is not 0.10% or less, the brightness will be impaired and at the same time the flash butt weld will become cloudy and the aesthetic appearance will be impaired.

0 Reasons for limiting the crystal grain shape Regarding the crystal grain shape, the reason why the ratio of the crystal grain size in the direction perpendicular to the crystal grain size in the plate thickness direction is 2.0 or less is as follows.
The orientation of the crystals in the alloy plate is made as close to isotropic as possible, and the orientation of the crystals in the weld heat-affected zone that occurs during flash butt welding is not much different from that of the base metal by chemical polishing and anodic oxidation. This is to ensure uniform processing of the welded parts.

0 Reasons for limiting the manufacturing process If the heating temperature of the ingot is less than 450°C, hot rolling properties are poor;
If the temperature exceeds 550°C, the hot rolling properties will improve, but the precipitates will become coarse and the brightness will decrease, so the temperature was set in the range of 450°C to 550°C.

Then, it is hot rolled at that heating temperature, and if moldability is particularly taken into account, it may be further cold rolled to measure the uniformity of the structure. There is no difference in brightness in any of the rolled plates.

The final annealing temperature ranges from 300°C to 450°C because the recrystallized grains become coarser after passing through the roll after flash butt welding, causing roughness and cracking during forming.

〔Example〕

(Left below) After melting and refining AΩ alloys having the five chemical compositions shown in Table 1, semi-continuous casting was performed to produce 450+nm x 1200++
An ingot of ++n×3000 mm was obtained.

After heating this ingot at 450 to 550°C for 1 to 5 hours, hot rolling was started at that temperature to form a hot rolled plate with a thickness of 4.5 squares. Next, final annealing was performed at 350°C for 2 hours.
A 5 mm soft material was obtained.

The thickness of each material is 4.5mm x width 225m
After cutting into 1l x 1180mm length, roll it into a short cylindrical shape,
Flash butt welded. Flash butt welding was carried out under conditions that had a so-called sound weld, in which no cracking or breakage occurred from the weld during subsequent roll forming.

The two-piece wheel rim was molded and surface-treated according to the process of flash butt welding and mounting under the above conditions, and the brightness of the two-piece wheel rim was visually determined. The results are shown in Table 2.

Note that the steps of molding and surface treatment are as follows.

Removing pars from flash butt welds - Roll forming into a 14-inch wheel rim → Polishing with an automatic cloth polishing device until lines from roll forming and traces of pars removal from welds disappear → Using phosphoric acid-based polishing liquid at 100°C × 2 minutes of chemical polishing - 10 minutes of washing under running water - IA/IA with 15% sulfuric acid electrolyte
dIn2, anodic oxidation treatment to a film thickness of 5μ → washing with running water for 10 minutes → sealing treatment.

〔Effect of the invention〕

As explained in detail above and shown in the examples, according to the method of manufacturing an aluminum alloy plate for two-piece wheel rim of the present invention, the obtained aluminum alloy plate has (1) high brightness, (2) ) Excellent brightness in flash butt welds, and (3) excellent quality characteristics with almost no difference in brightness between the base metal and the weld, making it ideal for bright two-piece wheel rim materials. The base material itself has high brightness, strength, and formability, making it suitable for three-piece wheel rim materials that do not require flash butt welding.

Claims (2)

[Claims] (1) By weight, Mg2.0~5.0%, Cu0.05~
0.15%, Si 0.10% or less, Fe less than 0.10%, Ti 0.005-0.10%, B 0.0001-0.
05%, other unavoidably contained impurity elements are each 0.05% or less and the total is 0.1% or less, the remainder, A
An aluminum alloy plate for a two-piece wheel rim, characterized in that the ratio of the crystal grain size in the direction perpendicular to the crystal grain size in the thickness direction is 2.0 or less. (2) By weight, Mg2.0~5.0%, Cu0.05~
0.15%, Si 0.10% or less, Fe less than 0.10%, Ti 0.005-0.10%, B 0.0001-0.
0.05%, other unavoidably contained impurity elements are each 0.05% or less, and the total is 0.1% or less, the balance A
An aluminum alloy ingot consisting of
A method for manufacturing an aluminum alloy plate for a two-piece wheel rim, which comprises heating at a temperature of 0.degree.