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Applications of Aluminum Alloys


Terms of Use

The data contained in the Technical Manual section has been compiled by United Aluminum. The data should be thoroughly evaluated and tested by technically skilled personnel before any use is made thereof. United Aluminum assumes no responsibility or liability for any use of this data and no warranties are given or implied by United Aluminum.

SELECTION GUIDE FOR ALUMINUM ALLOYS AND TEMPERS

 

 

RESISTANCE TO

 

Machinability

 

 

WELDABILITY

 

 

 

CORROSION

 

Brazeability

 

 

 

 

 

 

 

 

 

 

ALLOY

TEMPER

General

Stress- Corrosion Cracking

Working Cold

Gas

 

Arc

 

Resistance Spot and Seam

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1100

O

A

A

A

E

A

A

 

A

 

B

 

H12

A

A

A

E

A

A

 

A

 

A

 

H14

A

A

A

D

A

A

 

A

 

A

 

H16

A

A

B

D

A

A

 

A

 

A

 

H18

A

A

C

D

A

A

 

A

 

A

1350

O

A

A

A

E

A

A

 

A

 

B

 

H18

A

A

B

D

A

A

 

A

 

A

2024

O

D

D

D

 

D

 

D

 

T3, T4

D

C

C

B

D

C

 

B

 

B

 

T6

D

D

C

B

D

D

 

C

 

B

3003

O

A

A

A

E

A

A

 

A

 

A

 

H12

A

A

A

E

A

A

 

A

 

A

 

H14

A

A

B

D

A

A

 

A

 

A

 

H16

A

A

C

D

A

A

 

A

 

A

 

H18

A

A

C

D

A

A

 

A

 

A

 

H25

A

A

B

D

A

A

 

A

 

A

3004

O

A

A

A

D

B

B

 

A

 

B

 

H32

A

A

B

D

B

B

 

A

 

A

 

H34

A

A

B

C

B

B

 

A

 

A

 

H36

A

A

C

C

B

B

 

A

 

A

 

H38

A

A

C

C

B

B

 

A

 

A

3005

O

A

A

A

D

B

A

 

A

 

B

 

H12

A

A

B

D

B

A

 

A

 

A

 

H14

A

A

B

C

B

A

 

A

 

A

 

H16

A

A

C

C

B

A

 

A

 

A

 

H18

A

A

C

C

B

A

 

A

 

A

5005

O

A

A

A

E

B

A

 

A

 

B

 

H12

A

A

A

E

B

A

 

A

 

A

 

H14

A

A

B

D

B

A

 

A

 

A

 

H16

A

A

C

D

B

A

 

A

 

A

 

H18

A

A

C

D

B

A

 

A

 

A

 

H32

A

A

A

E

B

A

 

A

 

A

 

H34

A

A

B

D

B

A

 

A

 

A

 

H36

A

A

C

D

B

A

 

A

 

A

 

H38

A

A

C

D

B

A

 

A

 

A

SELECTION GUIDE FOR ALUMINUM ALLOYS AND TEMPERS

 

 

RESISTANCE TO

 

Machinability

 

 

WELDABILITY

 

 

 

CORROSION

 

Brazeability

 

 

 

 

 

 

 

 

 

 

ALLOY

TEMPER

General

Stress- Corrosion Cracking

Working Cold

Gas

 

Arc

 

Resistance Spot and Seam

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5050

O

A

A

A

E

B

A

 

A

 

B

 

H32

A

A

A

D

B

A

 

A

 

A

 

H34

A

A

B

D

B

A

 

A

 

A

 

H36

A

A

C

C

B

A

 

A

 

A

 

H38

A

A

C

C

B

A

 

A

 

A

5052

O

A

A

A

D

C

A

 

A

 

B

 

H32

A

A

B

D

C

A

 

A

 

A

 

H34

A

A

B

C

C

A

 

A

 

A

 

H36

A

A

C

C

C

A

 

A

 

A

 

H38

A

A

C

C

C

A

 

A

 

A

5056 &

O

A

B

A

D

D

C

 

A

 

B

5182

H12, H32

A

B

B

D

D

C

 

A

 

A

 

H14, H34

A

B

B

C

D

C

 

A

 

A

 

H16, H36

A

B-C

B-C

C

D

C

 

A

 

A

 

H18, H38

A

C

C

C

D

C

 

A

 

A

5657

H241

A

A

A

D

B

A

 

A

 

A

 

H25

A

A

B

D

B

A

 

A

 

A

 

H26

A

A

B

D

B

A

 

A

 

A

 

H28

A

A

C

D

B

A

 

A

 

A

6061

O

B

A

A

D

A

A

 

A

 

B

 

T4

B

B

B

C

A

A

 

A

 

A

 

T6

B

A

C

C

A

A

 

A

 

A

7075

O

D

D

D

 

D

 

B

 

T6

C

C

D

B

D

D

 

D

 

B

Corrosion ratings A through E are relative ratings in decreasing order of merit, based on exposures to sodium chloride solution by intermittent spraying or immersion. Alloys with A and B ratings can be used in industrial and seacoast atmospheres without protection. Alloys with C, D and E ratings generally should be protected at least on faying surfaces.

Stress-corrosion cracking ratings are based on service experience and on laboratory tests of specimens exposed to the 3.5% sodium chloride alternate immersion test.

A = No known instance of failure in service or in laboratory tests.

B = No known instance of failure in service; limited failures in laboratory tests of short transverse specimens.

C = Service failures with sustained tension stress acting in short transverse direction relative to grain structure; limited failures in laboratory tests of long transverse specimens.

D = Limited service failures with sustained longitudinal or long transverse stress.

Ratings A through D for Workability (cold), and A through E for Machinability, are relative ratings in decreasing order of merit.

Ratings A through D for Weldability and Brazeability are relative ratings defined as follows: A = Generally weldable by all commercial procedures and methods.

B = Weldable with special techniques or for specific applications which justify preliminary trials or testing to develop welding procedure and weld performance.

C = Limited Weldability because of crack sensitivity or loss in resistance to corrosion and mechanical properties. D = No commonly used welding methods have been developed.

RECOMMENDED MINIMUM BEND RADII FOR 90-DEGREE COLD FORMING OF SHEET

The radii listed are the minimum recommended for bending sheets and plates without fracturing in a standard press brake with air bend dies. Other types of bending operations may require larger radii or permit smaller radii. The minimum permissible radii will also vary with the design and condition of the tooling.

 

 

RADII FOR VARIOUS THICKNESS EXPRESSED

ALLOY

TEMPER

 

IN TERMS OF THICKNESS “t”

 

 

 

164 in.

 

132 in.

116 in.

 

18 in.

1100

O

0

 

0

0

 

0

 

H12

0

 

0

0

 

12t

 

H14

0

 

0

0

 

1t

 

H16

0

 

12t

1t

 

112t

 

H18

1t

 

1t

112t

 

212t

2024

O

0

 

0

0

 

12t

 

T3

212t

 

3t

4t

 

5t

 

T361

3t

 

4t

5t

 

6t

 

T4

212t

 

3t

4t

 

5t

 

T81

412t

 

512t

6t

 

712t

 

T861

5t

 

6t

7t

 

812t

3003

O

0

 

0

0

 

0

 

H12

0

 

0

0

 

12t

 

H14

0

 

0

0

 

1t

 

H16

12t

 

1t

1t

 

112t

 

H18

1t

 

112t

2t

 

212t

3004

O

0

 

0

0

 

12t

 

H32

0

 

0

12t

 

1t

 

H34

0

 

1t

1t

 

112t

 

H36

1t

 

1t

112t

 

212t

 

H38

1t

 

112t

212t

 

3t

3005

O

0

 

0

0

 

0

 

H12

0

 

0

0

 

12t

 

H14

0

 

12t

12t

 

112t

 

H16

12t

 

1t

1t

 

2t

 

H18

1t

 

112t

2t

 

212t

 

 

RADII FOR VARIOUS THICKNESS EXPRESSED

ALLOY

TEMPER

 

IN TERMS OF THICKNESS “t”

 

 

 

164 in.

 

132 in.

116 in.

 

18 in.

5005

O

0

 

0

0

 

0

 

H12

0

 

0

0

 

12t

 

H14

0

 

0

0

 

1t

 

H16

12t

 

1t

1t

 

112t

 

H18

1t

 

112t

2t

 

212t

 

H32

0

 

0

0

 

12t

 

H34

0

 

0

0

 

1t

 

H36

12t

 

1t

1t

 

112t

 

H38

1t

 

112t

2t

 

212t

5050

O

0

 

0

0

 

12t

 

H32

0

 

0

0

 

1t

 

H34

0

 

0

1t

 

112t

 

H36

1t

 

1t

112t

 

2t

 

H38

1t

 

112t

212t

 

3t

5052

O

0

 

0

0

 

12t

 

H32

0

 

0

1t

 

112t

 

H34

0

 

1t

112t

 

2t

 

H36

1t

 

1t

112t

 

212t

 

H38

1t

 

112t

212t

 

3t

5657

H25

0

 

0

0

 

1t

 

H27

1t

 

112t

212t

 

3t

6061

O

0

 

0

0

 

1t

 

T4

0

 

0

1t

 

112t

 

T6

1t

 

1t

112t

 

212t

7075

O

0

 

0t

1t

 

1t

 

T6

3t

 

4t

5t

 

6t

WATERSTAIN AND ITS PREVENTION

What is Waterstain?

Sometimes, when a coil of aluminum is unwound, some patches of white, chalky stains can be seen on the surface — this is a sure indication that the coil has been exposed to moisture at some time. Although usually white, the colors of the stains can also be brown, black or even show iridescent colors.

How does the staining occur?

Aluminum reacts with oxygen in the air to form a very tenacious oxide coating. It is this coating that gives aluminum its excellent corrosion resistance.

Under most conditions aluminum will not react with water at all, but aluminum is very prone to waterstaining when water is trapped between mating surfaces, such as when it is in the form of a tightly wound coil or in a stack of flat sheet.

Because oxygen from the air is prevented from reaching much of the aluminum surface, a chemical reaction occurs between the entrapped water and the aluminum, which results in a white hydroxide film forming instead of the usual transparent oxide film. The stains have no significant affect on the mechanical strength, but they can be unsightly and are often objectionable for esthetic reasons. They may cause processing problems where additional surface finishing or fabrication is to be performed.

Where does the water come from?

Obviously aluminum coils should not be stored in an area where they would be exposed to rain, or to water from a leaking roof or a leaking water pipe, or be exposed to any water splashes from nearby processing equipment. However, waterstain can still occur in an apparently dry storage area. This is because the most common source of water is condensation.

Air contains water in the form of water vapor. Warm air can hold more moisture than cold and so, if the air is chilled, it releases its moisture in the form of dew. A familiar example is the condensation of water that forms on the outside of a glass of cold liquid.

There is a risk of water condensing on an aluminum coil whenever the metal temperature is allowed to fall much below the surrounding air temperature, or, in technical terms, water will condense on aluminum if the temperature of the metal falls below the dew- point. Some examples of how this may occur:

  • Moving cold metal from a cold truck directly into a warm storage area can result in condensation, especially on a humid day. Instead, the unopened package of cold metal should be placed in a cooler area, free from drafts, and allowed to warm up slowly.
  • Moving metal from cold warehouse to a warm factory floor. Again, the metal should be allowed to warm up slowly.
  • Leaving a warehouse door open, allowing cold air to enter and cool the metal. If the air temperature suddenly rises as the day gets hotter then water may condense on the coil.

How does the water get in between the wraps?

It is often a source of amazement that waterstaining can occur all the way across a wide strip despite only the edges of a coil getting wet. However the water is forced into the wraps of the coil by a strong force called capillary action (the very tiny gaps between the wraps of the coil cause it to behave like a sponge soaking up water).

If there is evidence that the package has been exposed to moisture when you receive the metal, then this should be noted on the receiving papers and you should notify United Aluminum immediately.

If water is already in contact with the metal, the only sure way to avoid waterstain is to process the metal immediately. If this is not practical then remove the water as quickly as possible by using fans to blow air over the metal. Do not use hot air as this can cause further condensation to occur.

United Aluminum hopes that this information has provided a better understanding of waterstain. The value of the aluminum and assured production schedules justify the extra precautions.