120103h Flashcards
Which metal is lighter than Al
a) magnesium
b) copper
c) steel
d) manganese
a) magnesium
Al is a reactive metal.
What is meant by reactive?
A reactive metal is one that readily reacts with other elements.
Al reacts very quickly with O2 to form Al oxides
Al has a refractory oxide.
What is a refractory oxide?
Refactory oxide means that the oxide is difficult to melt, reduce or work.
The oxide of Al melts at a much higher temp than the parent metal.
How does the electrical and thermal conductivity of Al compare with that of mild steel?
The electrical and thermal conductivity of Al is aprox 4X that of mild steel
What are the aprox melting points of the following materials
a) Al
b) Al oxide
a) 660°C / 1220°F
b) 2037°C / 3700°F
Under the same conditions a section of Al would deflect ______ times as much as a similar section of mild steel
Under the same load, a section of Al would deflect 3X as much as a similar section of steel
What process may be used to enhance the Al oxide film for increased corrosion resistance
Anodizing increases the thickness of the oxide layer
The coefficient of linear expansion of Al is aprox:
a) equal to that of steel
b) half that of steel
c) twice that of steel
d) four times that of steel
2X that of steel
In the Al Association wrought iron Al alloy numbering system, the first digit indicates
a) the alloy group
b) the Al alloy
c) the Al purity over 99%
d) modifications to the original alloy
a) the alloy group
In the Al Association wrought iron Al alloy numbering system, the second digit indicates
a) the alloy group
b) the Al alloy
c) the Al purity over 99%
d) modifications to the original alloy
d) modifications to the original alloy
What is the purity of a 1050 Al alloy
1050 Al alloys are 99.5% pure
In the Al Association wrought iron Al alloy numbering system for 1XXX series the last 2 digits indicate :
a) the alloy group
b) the Al alloy
c) the Al purity over 99%
d) modifications to the original alloy
c) the Al purity over 99%
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 % of Mg added
b) the alloys added
Which Al alloy contains substantial amounts of Mg
a) AA 1030
b) AA 2014
c) AA 5356
d) AA 4043
c) AA 5356
What does the 4th digit indicate for Al alloy casting
a) min Al content
b) product form
c) modifications of the original alloy
d) type of heat treatment
b) product form
The Al wrought alloysin the groups 1XXX, 3XXX, & 5XXX series are:
a) heat treatable
b) non heat treatable
c) hardenable
d) temperable
b) non heat treatable
The Al wrought alloys in the groups 2XXX, 6XXX, & 7XXX series are:
a) heat treatable
b) non heat treatable
c) unworkable
d) unused
a) heat treatable
How can the mechanical properties of heat treated Al alloys be restored after welding
The properties may be restored by heat treating again
Heating an Al 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
d) solution heat treating
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
b) A ( anodized)
The mechanical properties of ____ -____ ____ Al alloys are improved by cold working and drawing
The mechanical properties of non-heat treatable Al alloys are improved by cold working and drawing
Which 2 filler metals may be used to weld most weldable Al alloys
a) ER1100 & ER3003
b) ER4043 & ER5356
c)ER5083 & ER 5454
d) ER6061 & ER 6351
b) ER4043 & ER5356
When welding a 6061-T6 alloy, which filler metal alloy is generally the best choice
ER4043
What is the primary consideration when selecting filler metals when using GMAW on Al?
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
b) matching base metal and filler metal chemistry and mechanical properties
Which is true of an ER5356 Al alloy?
a) there have been no modifications
b) It is 99.56% pure Al
c) It is a heat treatable Al
d) Mg is the major alloying element
d) Mg is the major alloying element
What type of alloy is an ER4043 filler wire
a) Al & silicon
b) Al & Mg
c) Al & manganese
d) silicon & manganese
a) Al & silicon
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
a) in the gun itself close to the contact tip
A pull type welding gun is designed to be used with:
a) hard wires
b) soft wires
c) solid core wires
d) tubular wires
b) solid core wires
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
b) push-pull system
Push - pull guns are an advantage when:
a) soft wires are taken through short liners
b) hard wires are taken through short lines
c) soft wires are taken through long liners
d) hard wires are taken through long liners
c) soft wires are taken through long liners
What type of metal transfer occurs with Al GMAW and 100% Ar shielding?
a) short circuiting
b) globular
c) dip transfer
d) spray
d) spray
What is the most likely cause of a porous, dirty weld bead?
a) drag technique
b) globular
c) dip transfer
d) spray transfer mode
a) drag technique
What is the most likely cause of the wire melting back on the contact tip?
a) wire feed speed to high
b) wire feed speed to slow
c) welding with a forehand technique
d) diameter of the wire matches the drive rolls
b) wire feed speed to slow
Al is the second most common metal after steel. What ore is Al obtained from?
a) cassiterite
b) bauxite
c) magnesite
d) horn silver
b) bauxite
Why is Al favoured for wide cross section of applications?
a) high tensile strength
B) high yield strength
c) high ductility
d) corrosion resistance, finishing options, high strength to weight ratio
d) corrosion resistance, finishing options, high strength to weight ratio
Why is Al generally added to molten steel during the steel making process:
a) to deoxidize and control grain growth
b) to replace some steel resulting in a lighter weight
c) to deoxidize and control elastic deformation of the steel
a) to deoxidize and control grain growth
Due to Al having an affinity for O2 what propellants is powdered Al used to manufacture?
Explosives and rocket engine propellants
What is the melting point of Iron?
a) 1500°F
b) 2050°F
c) 2750°F
d) 3025°F
c) 2750°F
Describe what is meant by the term; affinity:
A spontaneous or natural liking for
- the tendency of certain substances to combine with others
Describe what is meant by the term; cast:
Formed by placing liquid Al into a mould
Describe what is meant by the term; hot shortness:
The tendency towards brittleness and cracking while hot.
Describe what is meant by the term; wrought:
Mechanically shaped
- metals worked or shaped by mechanical means such as hammering but formed with care
Describe what is meant by the term; alloy:
A mixture of 2 or more elements of which one must be metal
Describe what is meant by the term; coefficient of linear expansion:
A ratio used as a multiplier to compare the expansion and contraction of a substance under different conditions of heat
Describe what is meant by the term; density:
The mass of a substance divided by its volume or the mass of a substance per unit of volume
Describe what is meant by the term; non-ferrous:
low to no iron content
Describe what is meant by the term; refractory:
A substance especially resistant to heat; having a high melting point
Describe what is meant by the term; thermal conductivity:
A measure of the speed at which heat flows through an object
Al has an electrical conductivity rating of about ______% that of copper?
a) 35%
b) 45%
c) 60%
d) 80%
c) 60%
Al coefficient of linear expansion is almost ___ that of steel
a) 1X
b) 2X
c) 8X
d) 10X
b) 2X
Al expands twice as much as an identical piece of steel for the same rise in temp
What is the melting point of Al?
a) 1050°F
b) 1220°F
c) 1320°F
d) 1530°F
b) 1220°F
Although Al has a relatively _____ melting point, its _______ thermal conductivity has a marked effect on welding due to the ______ heat input required.
Low melting point
high thermal conductivity
higher heat input required
Is Al magnetic? Y/N
No
Does Al spark? Y / N
No - that is why it is used for storage containers for explosive or flammable materials
Tensile strength, yield strength and ductility are 3 of what properties?
a) chemical properties
b) mechanical properties
c) physical properties
d) conductivity properties
b) mechanical properties
What is the melting point of Iron?
a) 1050°F
b) 1820°F
c) 2750°F
d) 3010°F
c) 2750°F
Why do we alloy Al?
to increase tensile, yield strength, & ductility
- changes its mechanical properties
What is the tensile strength of commercially pure Al?
a) 5000psi
b) 6000psi
c) 7000psi
d) 8000psi
c) 7000psi
Can some Al have tensile strengths as strong as 10,000psi? Y / N
Yes
What is yield strength?
is the measure of a load that causes permanent deformation
The 3 most important ________ properties of Al centre on how
1. it reacts with O2 (oxidation)
2. it may become subject to corrosion problems ( galvanic corrosion)
3. it can be finished to produce and retain desired properties ( anodizing)
chemical, physical, mechanical
The above describes the 3 most important CHEMICAL properties of Al
What is Al covered with naturally occurring ______ ______ film that gives Al its corrosion resistance
refractory oxide
The type of Al corrosion that takes place depends on multiple factors what is the prime factor?
its contact with other metals
- it can be minimized by insulating the Al from other metals with coatings or non-conductive dividers
What does anodizing do to the refractory oxide layer?
anodizing makes the refractory oxide layer thicker which increases the corrosion resistance & accepts colouring dies making them decorative
What must be removed from Al because it interferes with the welding process
refractory oxide layer
What do you use to clean the refractory oxide layer off the Al?
mechanical cleaning - SS wire brush, stainless power Bruch and SS wire wool
The aluminum association of America uses a 4 digit numbering system, what does the first digit shown as four in the example 4xxx
a) a modification of the alloy
b) Al-zinc alloys
c) the major alloy-group
d) pure aluminum
c) the major alloy-group
The tendency of certain substances to combine with others is the definition for:
a) attraction
b) inert
c) linear
d) affinity
d) affinity
Hydrogen in Al while welding is a primary cause of porosity. Which of the following could be a source of hydrogen that could affect the integrity of Al welds.
a) hydrated surface oxides
b) lubricants
c) filler rods
d) all of the above
d) all of the above
which conduit liner is recommended for th GMAW Al process
a) teflon
b) plastic
c) nylon
d) all of the above
d) all of the above
What is the purpose of Al when making carbon steel?
a) used as a deoxidizer
b) used as an oxidizer
c) used to increase hardness
d) used to promote thermal conductivity
a) used as a deoxidizer
What is the definition of hot shortness?
a) process where aluminum is heated to the point of melding
b) the ability of Al to with-stand high heats and maintain its strength
c) Al can become brittle in the weld area and will crack while hot
d) Al expansion rates are slightly greater than the rate of contraction
c) Al can become brittle in the weld area and will crack while hot
Aluminum is used extensively in steel making
a) to controll grain structure
b) to lower the melting temperatures
c) to prevent corrosion
d) all of the above
a) to controll grain structure
Al is obtained from:
a) iron ore
b) bauxite ore
c) copper ore
d) alumia ore
b) bauxite ore
Which statement is correct when referring to galvanic corrosion
a) any process that increases the refractory oxide causes corrosion
b) Al subjected to high temp service
c) Al that is continually subject to oil based environments
d) steel contacting Al, while in a moist environment
d) steel contacting Al, while in a moist environment
What type of wire brush do you use to remove oxide film on Al before welding
a) carbon steel
b) copper
c) stainless steel
d) Al
c) stainless steel
Where are the drive rolls located on a pull type system.
a) in the gun close to the contact tip
b) the same place as on the push system
c) at the drum where the wire is located
d) at the power source
a) in the gun close to the contact tip
When referring to trouble shooting which of the following could eliminate dirty welds
a) the push technique
b) spray transfer
c) clean the base metal with a stainless steel brush
d) all of the above
d) all of the above
Which of the following products could be referred to as wrought alloys?
a) wire
b) plates
c) extruded shapes
d) all of the above
d) all of the above
Which alloys exist in an ER5356 filler wire used in the GMAW process?
a) Al & manganese
b) Al & Cu
c) Al & Mg
d) Al & Si
c) Al & Mg
Which element combined with powdered Al creates a chemical reaction that generates heat used for rocket propellants.
a) Mg
b) Iron
c) O2
d) Hydrogen
c) O2
Al oxide melts at what temperature
a) a lower temp than Al
b) at the same temp than Al
c) at a higher temp than Al
d) it never melts
c) at a higher temp than Al
Al wrought alloys are designated by a four digit code. What does the 30 designate in this example 1030?
a) the Al group
b) no alloy modification
c) Al purity as a percent
d) Mg alloy series
c) Al purity as a percent
Which power source is preferred for GMAW when welding Al?
a) AC constant current
b) DC constant current
c) DC constant amperage
d) DC constant voltage
d) DC constant voltage
Which of the following is advantageous when using a push pull system with GMAW on Al?
a) allows for greater machine to work distances
b) provides positive control of wire speed
c) suited for feeding soft wire
d) all of the above
d) all of the above
Which alloys exist in an ER4043 filler wire used in the GMAW process
a) Si & Mg
b) Al & Mg
c) Al & Si
d) Al & Mg
c) Al & Si
