METHOD OF MANUFACTURING ALUMINUM-CONTAINING COMPOSITION AND PRODUCT MADE FROM SUCH COMPOSITION

Abstract

The present invention is concerned with a method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association. The method comprises a casting step, an extrusion step, and an anodizing step.

Description

FIELD OF THE INVENTION

The present invention is concerned with a manufacturing method of producing an aluminum-containing composition and a product made from such composition.

BACKGROUND OF THE INVENTION

Aluminum is an element that has been increasingly used in industries and products. There are many different types of aluminum compositions and these various types of compositions are generally defined or categorized according to their ingredients. Different aluminum compositions can also be defined according to industry standards. For example, the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys published by the Aluminum Association in February 2009 has defined the ingredients of different aluminum-containing compositions.

While one common characteristic of all aluminum-containing compositions is that they all contain a high weight percentage of aluminum, the exact ingredients and/or the weight percents of these ingredients in the compositions do differ from each other. Due to these differences, different aluminum-containing compositions have different physical properties. Even for the same aluminum-containing composition with substantially the same ingredients and same weight percents of the ingredients, there can be different methods of manufacturing. The use of different manufacturing methods can have significant implications on production efficiency, production cost, and product quality and product characteristics.

The present invention seeks to provide a method of manufacturing an aluminum-containing composition which has an enhanced production efficiency, production cost and product quality, or at least to provide an alternative to the public.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises 1) casting of billets, 2) extrusion for producing profiles, followed by 3) anodizing, wherein the casting of billets include a) preheating a casting oven, b) loading sources of aluminum-containing supplies to the oven and melting the aluminum-containing supplies, c) adding a first refining agent to the melting or molten aluminum-containing supplies, d) removing residues from the molten aluminum-containing supplies, e) adding metallic elements including metal elements, alloys and/or intermediate alloys to the aluminum-containing supplies in the oven, the metallic elements having magnesium-silicon, and maintaining a refining temperature from 680-700° C., f) adding a second refining agent and introducing nitrogen to the molten aluminum-containing supplies for refining and removal of air bubbles in the molten aluminum-containing supplies, g) casting aluminum produced from the oven, and h) effecting homogenization on casted billets of aluminum alloy from step g), and wherein the extrusion includes i) heating the casted billets from step h) to 420-430° C., j) heating an extrusion die to 450-460° C., k) setting an extrusion speed between 15-18 meters/minute, and l) hardening aluminum-containing profiles produced from extrusion by water spraying.

Preferably, in step a) the preheating time may be 1-2 hours.

In an embodiment, in step b) of the casting the sources of aluminum-containing supplies may include aluminum-containing waste profiles and/or aluminum/aluminum-containing ingots. The partial use of aluminum-containing waste profiles is allowable in this embodiment and yet the quality of final products is not affected. The advantage of using aluminum-containing waste profiles is to be able to recycle the waste profiles and to lower manufacturing cost.

In one embodiment, in step c) the first refining agent may take the form of refining powder.

In one specific embodiment, in step g) at a diameter of about 90 mm a casting speed of about 160-180 mm/minute may be used.

In another embodiment, in step h) the homogenization may be allowed for about 12 hours. After homogenization, the casted billets may be allowed for cooling, followed by cutting the billets into desired dimensions.

In yet another embodiment, in step k) an extrusion press machine pad may be used and the billets are being extruded at 420-430° C., thus generating the aluminum-containing profiles. The aluminum-containing profiles may then be cooled down to about 50° C., followed by steps of straightening and elongation of the profiles, wherein the elongation is less than 2%. The profiles may be subjected to thermo-mechanical aging for 2-3 hours at 190-200° C.

In another embodiment, in step (3) the anodizing includes at least of the following:

m) degreasing by an AC degreaser at room temperature for about 2-8 minutes;
n) performing alkaline etching control at a temperature from 45-80° C.;
o) performing polishing control for 1-5 minutes at a temperature from 90-95° C.;
p) performing neutralization control for 3-4 minutes at room temperature;
q) performing anodizing control at a temperature from 15-30° C.; and
r) performing sealing control for 5-8 minutes at room temperature.

Preferably, the steps a) to r) may be performed sequentially.

According to a second aspect of the invention, there is provided a method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises a step of casting of billets, wherein the casting step includes:—

• a) preheating a casting oven;
• b) loading sources of aluminum-containing supplies to the oven and melting the aluminum-containing supplies;
• c) adding a first refining agent to the melting or molten aluminum-containing supplies;
• d) removing residues from the molten aluminum-containing supplies;
• e) adding metallic elements including metal elements, alloys and/or intermediate alloys to the aluminum-containing supplies in the oven, the metallic elements having magnesium-silicon, and maintaining a refining temperature from 680-700° C.;
• f) adding a second refining agent and introducing nitrogen to the molten aluminum-containing supplies for fining and removal of air bubbles in the molten aluminum-containing supplies;
• g) casting aluminum produced from the furnace; and
• h) effecting homogenization on casted billets of aluminum alloy from step g).

Preferably, the steps a) to h) may be performed sequentially.

According to a third aspect of the present invention, there is provided a method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises a step of extrusion, the extrusion includes:—

• i) heating casted billets to 420-430° C.;
• j) heating an extrusion die to 450-460° C.;
• k) setting an extrusion speed between 15-18 meters/minute; and
• l) hardening aluminum-containing profiles produced from extrusion by water spraying.

Preferably, the steps i) to l) may be performed sequentially.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises a step of anodizing, including at least one or more of the following:

m) degreasing by an AC degreaser at room temperature for about 2-8 minutes;
n) performing alkaline etching control at a temperature from 45-80° C.;
o) performing polishing control for 1-5 minutes at a temperature from 90-95° C.;
p) performing neutralization control for 3-4 minutes at room temperature;
q) performing anodizing control at a temperature from 15-30° C.; and
r) performing sealing control for 5-8 minutes at room temperature.

Preferably, the steps m) to r) may be performed sequentially.

According to a fifth aspect of the present invention, there is provided with a product made from an aluminum-containing composition made from one of the above described methods.

BRIEF DESCRIPTION OF DRAWINGS

Some embodiments of the present invention will now be explained, with reference to the accompanied drawings, in which:—

FIG. 1 is a billet casting flow chart for 5050 alloy showing an embodiment of a casting procedure during production of an aluminum-containing composition according to some embodiments;

FIG. 2 is an extrusion flow chart for 5050 alloy showing an embodiment of an extrusion procedure during production of an aluminum-containing composition according to some embodiments; and

FIG. 3 is an anodizing flow chart for 5050 alloy showing an embodiment of an anodizing procedure during production of an aluminum-containing composition according to some embodiments.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention is concerned with a method of manufacturing an aluminum-containing composition. In the context of this description, the composition may also be referred as an aluminum alloy. Specifically, the aluminum-containing composition contains substantially 0.4 wt % silicon, 0.7% iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum. The aluminum-containing composition may also be defined according to international classification as Aluminum Alloy 5050, for example as defined by a publication called International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association. The publication is incorporated herein by way of reference in its entirety. For the sake of explanation, this aluminum-containing composition may also be addressed as subject aluminum-containing composition or “SA” hereinafter.

Although the present invention is concerned with SA, for comparison purpose another aluminum-containing composition is also depicted. This other aluminum-containing composition may be addressed as comparison aluminum-containing composition or “CA” hereinafter. It is to be noted that CA contains 0.2-0.6 wt % silicon, 0.15 wt % iron, 0.2 wt % copper, 0.05 wt % manganese, 0.45-0.9 wt % magnesium, 0.0 wt % chromium, 0.05 wt % zinc and 98.05-98.9 wt % aluminum. CA may also be defined as Aluminum Alloy 6463 according to the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association. The following table summarizes the chemical composition of SA and CA.

	CHEMICAL ANALYSIS
ALLOYS	Si	Fe	Cu	Mn	Mg	Cr	Zn
SA-5050	0.4	0.7	0.2	0.1	1.1-1.8	0.1	0.25
CA-6463	0.2-0.6	0.15	0.2	0.05	0.45-0.9	—	0.05

Table 1 summarizes the chemical composition of Alloys 5050 and 6463.

In order to appreciate the present invention it is to be mentioned that for a long time manufacturing aluminum alloy CA-6463 includes steps of polishing and oxidation. In order to produce aluminum alloy 6463 with desired surface quality, one requirement is to use aluminum ingots of high purity and moulds of high specification. Another requirement is to use higher operating temperatures during manufacturing. However, this would increase the cost of manufacturing and the moulds are subject to wear and tear quickly. This is undesirable in a manufacturing sense.

In view of this, an embodiment of the present invention allows manufacturing of aluminum alloy SA-5050 using waste profiles of aluminum and without using moulds of such high specification. The manufacturing of aluminum alloy SA-5050 according to present invention can increase production efficiency and cost. The following tables show the physical characteristics of aluminum alloys CA-6463 and SA-5050.

TABLE 2
Comparison of physical properties of alloys CA-6463 and SA-5050
	Tensile	Yield
Alloy	strength	strength	Elongation
condition	(Mpa)	(0.2 Mpa)	%	Remarks
CA-6463-T5	157	110	9	Standard
				requirements
SA-5050-T5	190	160	10	Actual data

TABLE 3
Comparison of surface shininess and extrusion
marks of alloys CA-6463 and SA-5050
Alloy	Shini-
condition	ness	Surface	Remarks
CA-6463-T5	400-550	Lining not obvious	Use daily production data
SA-5050-T5	500-600	Lining not obvious

By way of explanation, tempering is a heat treatment technique for alloys. It is to strengthen the alloys. “T” is a heat treatment designation code known by a skilled person in the art. It refers to Solution Heat Treated, and is usually used for products that have been strengthened by heat treatment, with or without subsequent strain hardening. Specifically, “T5” is a designation code and refers to products cooled from an elevated temperature in a shaping process and then artificially aged.

Experiments conducted during test manufacturing of alloys CA-6463 and SA-5050 show that molten aluminum alloy SA-5050 in the mould cavity has a good mobility or fluidity. As such, it can flow smoothly and achieve a high speed extrusion in an extrusion apparatus. Further, its high mobility will cause less wear and tear to the moulds and can thus ensure a longer life of the moulds.

Experiments and studies have shown that when compared with manufacturing alloy CA-6463, an embodiment of the method of the present invention for manufacturing alloy SA-5050 has a 20% increase in productivity, and the moulds have a 50% increase in production life span. These have generated significantly savings in cost. More importantly, due to the longer life span of the moulds, there is less down time during manufacturing.

During manufacturing of aluminum alloy SA-5050, there are three main steps, namely, 1) alloy casting, 2) alloy extrusion and 3) alloy anodizing. The following describes the embodiment of the manufacturing methodology of the present invention.

Alloy Casting

FIG. 1 illustrates the general flow of the alloy casting steps during manufacturing. The steps are set out as follows.

• 1. Reheat oven preferably for 1-2 hours.
• 2. Introduce preferably 500-800 kg of waste profiles onto the bottom of the oven, and then add aluminum ingots. The waste profiles refer to aluminum alloy made from previous manufacturing and are recycled.
• 3. Heat the oven until the aluminum ingots melt completely.
• 4. Add impurity removal agents, the amount of which is preferably equals to 0.15 wt % of the liquid or molten aluminum alloy in the oven. Stir and mix them together until impurities rise and/or float to the surface of the aluminum alloy. When the impurities appear stable on the liquid surface, they can be removed from the surface easily.
• 5. Add other alloys and/or an intermediate alloy. After the alloys completely melt, take a sample for analysis. One preferred intermediate alloy which can be used is magnesium-silicon.
• 6. Adjust the alloy composition in the oven. Start refining and initiate air bubbles removal process at 680-700° C. Add refining powders, the amount of which should be about 0.15 wt % of the liquid/molten aluminum, into a refining apparatus and connect the apparatus with nitrogen supply. Activate the apparatus until the refining agents spurt out, and then insert the pipe from the apparatus into the liquid/molten aluminum to start the refining process. The pipe outlet is kept away from the bottom of the oven for 10-15 cm. The pipe is then moved evenly and impurities and air bubbles are removed from the liquid aluminum alloy until the refining process finishes.
• 7. The casting speed is kept at substantially 160-180 mm/minute billet at diameter of 90 mm.
• 8. Homogenization is then conducted for about 12 hours at 470-480° C. After the billets cool down naturally, cut the billets into pieces. Homogenization is a type of heat treatment primarily eliminating the consequences of micro-segregation and to raise the level of properties for shaped castings. Homogenization can increase the technological formality before subsequent thermo-mechanical treatments.

Alloy Extrusion

FIG. 2 illustrates the general flow of the alloy extrusion steps during manufacturing. The steps are set out as follows.

• 1. Put casted billets into the oven. The casted billets are heated up to 420-430° C.
• 2. Heat the extrusion die to 450-460° C.
• 3. Maintain the temperature of extrusion press machine pad at 420-430° C.
• 4. Set extrusion speed at 15-18 meters/minute.
• 5. Use water spraying to cool down the aluminum profile while it is coming out from the press machine.
• 6. Straighten the aluminum profile after it cools down to about 50° C. The extent of elongation is kept at below 2%.
• 7. Carry out thermo-mechanical aging process for 2-3 hours. The temperature of thermo-mechanical aging is set between 190-200° C.

Alloy Anodizing

In an embodiment, the anodizing includes at least one or more of the following:
1. degreasing by an AC degreaser at room temperature for about 2-8 minutes;
2. performing alkaline etching control at a temperature from 45-80° C.;
3. performing polishing control for 1-5 minutes at a temperature from 90-95° C.;
4. performing neutralization control for 3-4 minutes at room temperature;
5. performing anodizing control at a temperature from 15-30° C.; and
6. performing sealing control for 5-8 minutes at room temperature.

Highlights of Above Manufacturing Steps

During the above manufacturing, an alloy or intermediate alloy (magnesium-silicon) is used. This allows a lower casting temperature of 680-700° C. This is technically advantageous because on one hand it can reduce wear and tear of the moulds and reduce the grain size of the aluminum alloy product. On the other hand, it creates a better alloy condition for subsequent extrusion.
During extrusion using other aluminum alloy manufacturing methodologies, typically a rather high temperature at 500-520° C. is required. To the contrary, the extrusion temperature required in the above methodology of the present invention is much lower at 420-430° C. Yet, the desired physical properties can still be attained. Specifically, with this lower temperature fewer grains are produced in the alloy product. The surface condition is smoother and the surface shininess is increased. All these attributes favor subsequent oxidation and polishing steps.

During polishing and oxidation using other aluminum alloy manufacturing methodologies, the operating temperature is usually at 95-105° C. It is typically only within this temperature range for the polishing step to produce a desired degree of shininess. However, the side effect of adopting this operating temperature is that there is usually associated with flaws such as sandy, delaminating or foggy surface with flow marks. On the other hand, if the operating temperature were low, there would be a whitish surface and lack of shininess. To the contrary, the operating temperature of the polishing and oxidation steps of the present invention can be carried out at 90-95° C. and yet the advantages described using conventional oxidation and polishing methods are preserved and at the same time a lower energy cost.

It should be understood that embodiments of the invention are described by way of examples only. A skilled person in the art will be aware of the prior art which is not explained in the above for brevity purpose.

Claims

1. A method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises:

(1) casting of billets;

(2) extrusion for producing profiles; followed by

(3) anodizing;

wherein said casting of billets includes:

a) preheating a casting oven;

b) loading sources of aluminum-containing supplies to the oven and melting the aluminum-containing supplies;

c) adding a first refining agent to the melting or molten aluminum-containing supplies;

d) removing residues from the molten aluminum-containing supplies;

e) adding metallic elements including metal elements, alloys and/or intermediate alloys to the aluminum-containing supplies in the oven, the metallic elements having magnesium-silicon alloy, and maintaining a refining temperature from 680-700° C.;

f) adding a second refining agent and introducing nitrogen to the molten aluminum-containing supplies for refining and removal of air bubbles in the molten aluminum-containing supplies;

g) casting aluminum produced from the oven; and

h) effecting homogenization on casted billets of aluminum alloy from step g); and

wherein said extrusion includes:

i) heating the casted billets from step h) to 420-430° C.;

j) heating an extrusion die to 450-460° C.;

k) setting an extrusion speed between 15-18 meters/minute; and

l) hardening aluminum-containing profiles produced from extrusion by water spraying.

2. A method as claimed in claim 1, wherein in step a) the preheating time is 1-2 hours.

3. A method as claimed claim 1, wherein in step b) the sources of aluminum-containing supplies include aluminum-containing waste profiles and/or aluminum/aluminum-containing ingots.

4. A method as claimed in claim 1, wherein in step c) the first refining agent takes the form of refining powder.

5. A method as claimed in claim 1, wherein in step g) at a diameter of about 90 mm a casting speed of about 160-180 mm/minute is used.

6. A method as claimed in claim 1, wherein in step h) the homogenization is allowed for about 12 hours.

7. A method as claimed in claim 6, wherein after the homogenization the casted billets are allowed for cooling, followed by cutting the billets into desired dimensions.

8. A method as claimed in claim 1, wherein in step k) the billets are being extruded by an extrusion press machine pad at 420-430° C., thus generating the aluminum-containing profiles.

9. A method as claimed in claim 8, wherein the aluminum-containing profiles are then cooled down to about 50° C., followed by steps of straightening and elongation of the profiles, wherein the elongation is less than 2%.

10. A method as claimed in claim 9, wherein the profiles are subjected to thermo-mechanical aging for 2-3 hours at 190-200° C.

11. A method as claimed in claim 1, wherein steps a) to l) are performed sequentially.

12. A method as claimed in claim 1, wherein in step (3) the anodizing includes at least one or more of the following:

m) degreasing by an AC degreaser at room temperature for about 2-8 minutes;

n) performing alkaline etching control at a temperature from 45-80° C.;

o) performing polishing control for 1-5 minutes at a temperature from 90-95° C.;

p) performing neutralization control for 3-4 minutes at room temperature;

q) performing anodizing control at a temperature from 15-30° C.; and

r) performing sealing control for 5-8 minutes at room temperature.

13. A method as claimed in claim 12, wherein steps m) to r) are performed sequentially.

14. A method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises a step of casting of billets, wherein said casting step includes:—

a) preheating a casting oven;

b) loading sources of aluminum-containing supplies to the oven and melting the aluminum-containing supplies;

c) adding a first refining agent to the melting or molten aluminum-containing supplies;

d) removing residues from the molten aluminum-containing supplies;

e) adding metallic elements including metal elements, alloys and/or intermediate alloys to the aluminum-containing supplies in the oven, the metallic elements having magnesium-silicon, and maintaining a refining temperature from 680-700° C.;

f) adding a second refining agent and introducing nitrogen to the molten aluminum-containing supplies for refining and removal of air bubbles in the molten aluminum-containing supplies;

g) casting aluminum produced from the oven; and

h) effecting homogenization on casted billets of aluminum alloy from step g).

15. A method as claimed in claim 14, wherein steps a) to h) are performed sequentially.

16. A method of manufacturing an aluminum-containing composition, wherein the composition having substantially 0.4 wt % silicon, 0.7 wt % iron, 0.2 wt % copper, 0.1 wt % manganese, 1.1-1.8 wt % magnesium, 0.1 wt % chromium, 0.25 wt % zinc and 96.45-97.15 wt % aluminum, or being Aluminum 5050 as defined by the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys of the Aluminum Association, wherein the method comprises a step of extrusion, said extrusion includes:—

i) heating casted billets to 420-430° C.;

j) heating an extrusion die to 450-460° C.;

k) setting an extrusion speed between 15-18 meters/minute; and

l) hardening aluminum-containing profiles produced from extrusion by water spraying.

17. A method as claimed in claim 16, wherein steps i) to l) are performed sequentially.