120103h Aluminum and Aluminum Welding

Question 1

Question: Which metal is lighter than aluminum?
a) magnesium, b) copper, c) steel, d) manganese

Answer 1

Answer: a) magnesium
Explanation: Magnesium is lighter than aluminum, highlighting the importance of material selection in welding and fabrication for achieving desired weight and strength characteristics.

Question 2

Question: Aluminum is a reactive metal. What is meant by reactive?

Answer 2

Answer: A reactive metal readily reacts with other elements. Aluminum reacts quickly with oxygen to form aluminum oxides.
Explanation: Understanding aluminum’s reactive nature is crucial for welders, as it affects how the metal behaves during the welding process, particularly in terms of oxidation and corrosion.

Question 3

Question: Aluminum has a refractory oxide. What is refractory oxide?

Answer 3

Answer: Refractory oxide means the oxide is difficult to melt, reduce, or work. The oxide of aluminum melts at a much higher temperature than the parent metal.
Explanation: The concept of refractory oxide is significant in welding, as it influences the melting behavior of aluminum, impacting welding techniques and temperature management.

Question 4

Question: How does the electrical and thermal conductivity of aluminum compare with that of mild steel?

Answer 4

Answer: The electrical and thermal conductivity of aluminum is approximately four times that of mild steel.
Explanation: This knowledge is important for welders to manage heat distribution and electrical characteristics during the welding process.

Question 5

Question: What are the approximate melting points of the following materials?
a) aluminum
b) aluminum oxide

Answer 5

Answer: a) 660°C (1220°F), b) 2037°C (3700°F)
Explanation: Knowing the melting points aids in selecting appropriate welding settings and techniques for aluminum and its compounds.

Question 6

Question: Under the same conditions, a section of aluminum would deflect __ times as much as a similar section of mild steel.

Answer 6

Answer: Under the same load, a section of aluminum would deflect three times as much as a similar section of steel.
Explanation: This information is vital for understanding the structural behavior of aluminum under load, influencing design and welding choices.

Question 7

Question: What process may be used to enhance the aluminum oxide film for increased corrosion resistance?

Answer 7

Answer: Anodizing increases the thickness of the oxide layer.
Explanation: Anodizing is a surface treatment method that enhances corrosion resistance, important for the longevity and durability of aluminum weldments.

Question 8

Question: The coefficient of linear expansion of aluminum is approximately:
a) equal to that of steel.
b) half that of steel.
c) twice that of steel.
d) four times that of steel.

Answer 8

Answer: c) twice that of steel.

Question 9

Question: In the Aluminum Association wrought aluminum alloy numbering system, the first digit indicates:
a) the alloy group, b) the aluminum alloy, c) the aluminum purity over 99.00%, d) modifications to the original alloy

Answer 9

Answer: a) the alloy group
Explanation: The first digit in the numbering system identifies the primary alloying element or the alloy group, providing a quick reference to the alloy’s main characteristics.

Question 10

Question: In the Aluminum Association wrought aluminum alloy number system, the second digit indicates:
a) the alloy group, b) the aluminum alloy, c) the aluminum purity over 99.00%, d) modifications to the original alloy

Answer 10

Answer: d) modifications to the original alloy
Explanation: The second digit indicates if there have been modifications to the original alloy, which is crucial for understanding the specific characteristics and suitability of the alloy for different welding applications.

Question 11

Question: What is the purity of a 1050 aluminum alloy?

Answer 11

Answer: 1050 aluminum alloys are 99.50% pure.
Explanation: This indicates the high level of purity of 1050 aluminum, which can affect its welding characteristics, such as corrosion resistance and electrical conductivity.

Question 12

Question: In the Aluminum Association wrought aluminum alloy number system for 1XXX series, the last two digits indicate:
a) the alloy group, b) the aluminum alloy, c) the aluminum purity is over 99.00%

Answer 12

Answer: c) the aluminum purity is over 99.00%
Explanation: In the 1XXX series, the last two digits (after the initial ‘1’) specify the minimum aluminum content, which is important for determining the alloy’s general properties.

Question 13

Question: What does the number 43 indicate in the filler wire designation ER4043?
a) the carbon content, b) the alloys added, c) the minimum purity, d) the percentage of magnesium added

Answer 13

Answer: b) the alloys added
Explanation: The ‘43’ in ER4043 identifies the specific alloys added to the filler wire, which influences its welding characteristics and compatibility with different base metals.

Question 14

Question: Which aluminum alloy contains substantial amounts of magnesium?
a) AA 1030, b) AA2014, c) AA 5356, d) AA4043

Answer 14

Answer: c) AA 5356
Explanation: AA 5356 is known for containing significant amounts of magnesium, affecting properties like strength, corrosion resistance, and weldability.

Question 15

Question: What does the fourth digit indicate for an aluminum alloy casting?
a) minimum aluminum content, b) product form, c) modifications of the original alloy, d) type of heat treatment

Answer 15

Answer: b) product form
Explanation: The fourth digit in the aluminum alloy casting designation system specifies the product form, which is essential for understanding the intended use and manufacturing process of the alloy.

Question 16

Question: The aluminum wrought alloys in the groups 1XXX, 3XXX, and 5XXX series are:
a) heat-treatable, b) non-heat treatable, c) hardenable, d) temperable

Answer 16

Answer: b) non-heat treatable
Explanation: The 1XXX, 3XXX, and 5XXX series of aluminum wrought alloys are non-heat treatable, which impacts how they respond to welding and post-welding treatments.

Question 17

Question: The aluminum wrought alloys in the groups 2XXX, 6XXX, and 7XXX series are:
a) heat-treatable, b) non-heat treatable, c) unworkable, d) unused

Answer 17

Answer: a) heat-treatable
Explanation: These series of aluminum wrought alloys are heat-treatable, which means they can be strengthened through heat treatment processes, making this knowledge essential for appropriate welding and post-welding treatments.

Question 18

Question: How can the mechanical properties of heat-treated aluminum alloys be restored after welding?

Answer 18

Answer: The properties can be restored by heat-treating again.
Explanation: Post-weld heat treatment is crucial for restoring the mechanical properties of heat-treated aluminum alloys that may have been altered during the welding process.

Question 19

Question: Heating an aluminum alloy to a temperature below its melting point for a specified period of time and then quenching from this temperature is called:
a) tempering, b) hardening, c) aging, d) solution heat-treating

Answer 19

Answer: d) solution heat-treating
Explanation: Solution heat-treating is a key process in the heat treatment of aluminum alloys, involving heating and then rapid cooling to achieve desired mechanical properties.

Question 20

Question: Non-heat treatable wrought alloys are designated with several levels of mechanical properties. Which does not indicate a mechanical property designation?
a) H1 (work hardened only), b) A (anodized), c) O (fully annealed), d) F (as fabricated)

Answer 20

Answer: b) A (anodized)
Explanation: ‘A’ for anodized is not a mechanical property designation but rather refers to a surface treatment process, unlike the other options which describe the mechanical state of the alloy.

Question 21

Question: The mechanical properties of ___________ aluminum alloys are improved by cold working and drawing.

Answer 21

Answer: non-heat treatable
Explanation: Cold working and drawing are processes that can enhance the mechanical properties of aluminum alloys, such as strength and ductility.

Question 22

Question: Which two filler metals may be used to weld most weldable aluminum alloys?
a) ER 1100 and ER3003, b) ER4043 and ER5356, c) ER5083 and ER5454, d) ER6061 and ER6351

Answer 22

Answer: b) ER4043 and ER5356
Explanation: ER4043 and ER5356 are commonly used filler metals for welding aluminum alloys due to their compatibility and welding performance.

Question 23

Question: When welding a 6061-T6 alloy, which filler metal alloy is generally the best choice?

Answer 23

Answer: ER4043
Explanation: ER4043 is often chosen for welding 6061-T6 alloy because of its good welding properties and compatibility with the base metal.

Question 24

Question: What is the primary consideration when selecting a filler metal when using GMAW on aluminum?
a) the amperage and voltage settings, b) matching base metal and filler metal chemistry and mechanical properties, c) the temper designation of the base metal, d) the type of joint to be welded

Answer 24

Answer: b) matching base metal and filler metal chemistry and mechanical properties
Explanation: The compatibility of filler metal with the base metal in terms of chemistry and mechanical properties is crucial for achieving a quality weld in GMAW processes on aluminum.

Question 25

Question: Which is true of an ER5356 aluminum alloy? a) There have been no modifications, b) It is 99.56% pure aluminum, c) It is a heat-treatable aluminum, d) Magnesium is the major alloying element

Answer 25

Answer: d) Magnesium is the major alloying element Explanation: ER5356 aluminum alloy is characterized by its significant magnesium content, which influences its properties and suitability for specific welding applications.

Question 26

Question: What type of alloy is an ER4043 filler wire? a) aluminum and silicon, b) aluminum and magnesium, c) aluminum and manganese, d) silicon and manganese

Answer 26

Answer: a) aluminum and silicon Explanation: ER4043 is an aluminum-silicon alloy filler wire commonly used in aluminum welding for its good fluidity, smooth bead appearance, and less sensitivity to weld cracking.

Question 27

Question: Where are the drive rolls located on a pull type drive system? a) in the gun itself, close to the contact tip, b) in the main wire feed unit, c) on the drum some distance behind the wire feeder, d) the same place as on a push type system

Answer 27

Answer: a) in the gun itself, close to the contact tip Explanation: In a pull type drive system, the drive rolls are located in the gun itself, near the contact tip. This setup helps in feeding soft wires like aluminum through the gun without causing issues like wire tangling or deformation.

Question 28

Question: A pull type welding gun is designed to be used with: a) hard wires, b) soft wires, c) solid core wires, d) tubular wires

Answer 28

Answer: b) soft wires Explanation: Pull type welding guns are particularly suited for soft wires, such as aluminum, as they help in minimizing wire feeding problems associated with softer materials.

Question 29

Question: What type of wire drive system allows greater machine-to-work distances? a) push system, b) push-pull system, c) 2 drive roll system, d) 4 drive roll system

Answer 29

Answer: b) push-pull system Explanation: The push-pull system is designed to allow for greater distances between the welding machine and the workpiece. This system combines the features of both push and pull systems for efficient wire feeding over long distances.

Question 30

Question: Push-pull guns are an advantage when: a) soft wires are taken through short liners, b) hard wires are taken through short liners, c) soft wires are taken through long liners, d) hard wires are taken through long liners

Answer 30

Answer: c) soft wires are taken through long liners Explanation: Push-pull guns provide an advantage in situations where soft wires, like aluminum, need to be fed through long liners, as they help reduce feeding issues and ensure consistent wire delivery.

Question 31

Question: What type of metal transfer occurs with aluminum GMAW and 100% argon shielding? a) short circuiting, b) globular, c) dip transfer, d) spray

Answer 31

Answer: d) spray Explanation: When welding aluminum using GMAW (Gas Metal Arc Welding) with 100% argon shielding gas, spray transfer is the typical mode of metal transfer. This method is characterized by a steady stream of small molten droplets across the arc.

Question 32

Question: What is the most likely cause of a porous, dirty weld bead? a) drag technique, b) push technique, c) brushing the aluminum with a stainless steel brush, d) spray transfer mode

Answer 32

Answer: a) drag technique Explanation: Porous and dirty weld beads in aluminum welding are often caused by the drag technique. This technique can lead to inadequate gas coverage, resulting in contamination and porosity in the weld.

Question 33

Question: What is the most likely cause of the wire melting back onto the contact tip? a) wire feed speed too high, b) wire feed speed too low, c) welding with a forehand technique, d) diameter of the wire matches the drive rolls

Answer 33

Answer: b) wire feed speed too low Explanation: When the wire melts back onto the contact tip, it's often because the wire feed speed is too low. Insufficient wire feed speed doesn't provide enough wire to the arc, causing the wire to melt back towards the contact tip.