120102d Flashcards
1
Q
The extent of the change of the grain structure in the heat affected zone depends upon
A) the temperature to which the metal is subjected
B) the composition of the steel
C) rate of cooling
D) all of the above
A
D) all of the above
2
Q
Which of the listed heat treatments alters the grain structure of the well deposit and heat affected zone
A) stress relief
B) tempering
C) normalizing
D) preheating
A
C) normalizing
3
Q
Temperature refers to the
A) intensity of heat
B) amount of heat
C) volume of heat
D) quality of heat
A
A) intensity of heat
4
Q
The movement of heat within the body of a material is called:
A) radiation
B) conduction
C) convection
D) transference
A
B) conduction
5
Q
The transfer of heat from one body to another is called
A) radiation
B) conduction
C) convection
D) transference
A
C) convection
6
Q
The movement of heat and air is called
A) radiation
B) conduction
C) convection
D) transference
A
A) radiation
7
Q
The rate of thermal conductivity refers to the:
A) melting temperature of a metal
B) BTU output of an oxy welding tip
C) speed heat travels within a material
D) time required to melt through the metal
A
C) speed heat travels within a material
8
Q
The material that requires the lowest heat input for welding because of its poor thermal conductivity is
A) mild steel
B) brass
C) aluminum
D) copper
A
A) mild steel
9
Q
The material that requires the greatest heat input for welding because of its high thermal conductivity is:
A) aluminum
B) mild steel
C) stainless steel
D) cast-iron
A
A) aluminum
10
Q
Restrained expansion of metal when it is heated results in:
A) internal cracking
B) dimensional upset
C) internal stress
D) surface hardening
A
B) dimensional upset
11
Q
Unrestrained expansion and contraction of metal when it is heated and allowed to cool slowly produces:
A) internal cracking
B) dimensional upset
C) no appreciable change
D) surface hardening
A
C) no appreciable change
12
Q
The dimensional upset that occurs when expansion is restrained maybe used to good advantage to
A) remove broken studs
B) use jigs and fixtures
C) remove excess weld reinforcement
D) weld around the neutral access
A
A) remove broken studs
13
Q
What is the result of welding a section when both expansion and contraction are restrained
A) excessive warping
B) loss of dimensions
C) very high stress
D) good sound weld
A
C) very high stress
14
Q
On which of the following jobs would expansion and contraction work in your favour?
A) welding, a joint subject to a high degree of restraint
B) when repairing an exhaust manifold
C) when repairing spokes on a flywheel
D) welding, aluminum tire rims
A
C) when repairing spokes on a flywheel
15
Q
Preheating heavy sections can help:
A) prevent weld bead cracking
B) increase internal stress
C) increase tensile strength
D) produce a fine grain structure
A
A) prevent weld bead cracking
16
Q
Metals that are to be welded, and that are low in ductility are usually preheated in order to:
A) promote fine grain size
B) slow the quench rate
C) improve the hardenability
D) increase welding stress
A
B) slow the quench rate
17
Q
Which of the following cannot be accomplished with a post welded heat treatment?
A) annealing
B) normalizing
C) stress relieving
D) distortion control
A
D) distortion control
18
Q
What is the soaking time required to stress relieve a steel weldment that is 1 inch thick?
A) one hour
B) two hours
C) three hours
D) four hours
A
A) one hour
19
Q
The annealing of a steel fabrication should:
A) decrease distortion
B) increase hardness
C) decrease ductility
D) decrease tensile strength
A
D) decrease tensile strength
20
Q
What effect does preheating have on a steel weldment ?
A) it increases tensile strength and ductility
B) it decreases tensile strength and ductility
C) it increases tensile strength, and decreases ductility
D) decreases tensile strength and increases ductility
A
D) decreases tensile strength and increases ductility
21
Q
The heat treating process that brings a material to its softest, toughest, weakest state is:
A) annealing
B) normalizing
C) stress relieving
D) Tempering
A
A) annealing
22
Q
Heating steel above its upper critical temperature and cooling in still air, describes a heat treatment known as:
A) annealing
B) normalizing
C) stress relieving
D) tempering
A
B) normalizing
23
Q
The temperature range for stress relieving is
A) 870°C (1600°F) to 980°C (1800°F)
B) 760°C (1400°F) to 870°C (1600°F)
C) 595°C (1100°F) to 700°C (1300°F)
D) 425°C (800°F) to 535°C (1000°F)
A
C) 595°C (1100°F) to 700°C (1300°F)
24
Q
Tempering is a___________ process.
A) case hardening
B) preheating
C) hardening
D) toughening
A
D) toughening
25
To produce grain structure, uniformity throughout the weldment and critical areas you would:
A) temper
B) stress relief
C) normalize
D) preheat
C) normalize
26
Heating above the upper critical temperature followed by a rapid quench describes:
A) stress relieving
B) normalizing
C) tempering
D) hardening
D) hardening
27
Heating below the lower critical temperature, followed by a rapid quench describes:
A) stress relieving
B) normalizing
C) tempering
D) annealing
C) tempering
28
A temperature indicating crayon marked at 150°C (300°F) is used for:
A) hardening
B) preheating
C) stress relieving
D) annealing
B) preheating
29
Which of the following is a temperature sensing device
A) thermograph
B) inclinometer
C) barometer
D) pyrometer
D) pyrometer
30
The HAZ stretches _____ from the weld until the grain structure of the parent metal has been unaffected by the heat of welding
a) parallel
b) perpendicular
c) towards
d) away
d) away
31
What are 4 factors that can affect the HAZ that must be considered before you make a weld procedure?
Any of the following are correct
- welding process
- type and size of the electrode
- current setting
- travel speed and # of passes needed
- type of material
- carbon content
- thickness of the material
- amount of preheat used (if used)
- ambient air temp
32
Typical grain pattern of single and mult-pass welds could be described as:
a) conical grain pattern
b) cross-hatch grain pattern
c) columnar grain pattern
d) helical grain pattern
c) columnar grain pattern
33
The HAZ appears in the _____ portion & consists of these areas
- the solid/liquid transition zone, the grain growth zone,
- the recrystalized zone and
- the partially transformed zone.
a) surface
b) center
c) unaffected base metal
b) center
34
The end result with a multipass weld is a _______ grain structure in the weld and HAZ.
a) coarser
b) finer
c) longer
d) shorter
b) finer
35
When ________ stress levels at dynamic loading and severe service conditions are required, the structure of the HAZ becomes very important
a) lower
b) higher
c) static
d) dynamic
b) higher
36
As a general rule a ______ grain structure makes a stronger weld
a) granular
c) columnar
d) finer
d) coarser
d) finer
37
Finer grain structure is preferred especially where ______ notch toughness values are required.
a) lower
b) mild
c) higher
c) higher
38
A welding procedure that generates to fine a grain structure may result in the formation of a hard and brittle _________ structure that is prone to cracking
a) ferritic
b) austenitic
c) martensitic
d) duplex
c) martensitic
39
Martensite typically only occurs in materials with ≥ ______ carbon content
a) 0.02%
b) 0.05%
c) 0.25%
d) 0.35%
d) 0.35%
40
The term temperature refers to a degree or intensity. True or False
True & expressed as °F or °C
41
The term heat expresses a volume or quantity measured in BTU or joules (J)
True or False
True
42
Match the gas with the correct info
Acetylene, Propane
a) 4580°F , 2500 BTU/ ft^3
b) 5600°F, 1470 BTU/ft^3
Acetylene : b
Propane : a
43
Is each statement true or false
You can change the amount of heat per unit of time through manipulation of torch valves or by using different sizes of heating tips.
You cannot, change the temperature of a neutral flame because this temperature determined by the chemical reaction
Both are true
44
What are the 3 forms of heat transfer?
Radiation, Convection, Conduction
45
What type of heat transfer does this describe?
Heat that travels on light waves.
- you can fee the heat radiating from the object
a) radiation
b) convection
c) conduction
d) transference
a) radiation
46
What type of heat transfer does this describe?
Heat from one body to another by the movement of a gas
- the heat is transferred to your hand by means of _____.
a) radiation
b) convection
c) conduction
d) transference
b) convection
47
What type of heat transfer does this describe?
The transfer of heat within a body. The rate at which a material can transfer heat within itself is known as its thermal _____ rate.
a) radiation
b) convection
c) conduction
d) transference
c) conduction
48
The rate at which a material can transfer heat within itself is known as its _________rate.
a) thermal expansion
b) thermal potential
c) thermal conductivity
d) thermal contraction
c) thermal conductivity
49
Expansion is usually associated with a rise in temp. true or false
true
50
__________ occurs when the metal is in a solid condition and has not reached its transition temperature. The transition temperature for steel is 1333°F.
a) fluid expansion
b) transition expansion
c) solid expansion
d) free expansion
c) solid expansion
51
________ takes place above the transition temperature. Steel will transition or change from one crystalline form to another. During this transition, steel remains in a solid state.
a) fluid expansion
b) transition expansion
c) solid expansion
d) free expansion
b) transition expansion
52
__________ occurs in molten metal
a) fluid expansion
b) transition expansion
c) solid expansion
d) free expansion
a) fluid expansion
53
With restrained expansion and contraction, when the cooled bar's dimensions are shortened and thickened this condition is called?
a) restrained upset
b) contraction disruption
c) directional inequality
d) directional upset
d) directional upset
54
When you are welding, both expansion and contraction are often restrained because you are heating the metal in a localized area and moving the heat along the weld joint.
The metal acts like a vise to restrain the expansion while the metal is being heated; it then acts like a clamp to restrain the contraction as the metal cools.
The frequent result is either a buildup of ______ in the joint area or a _____ if the metal is free to move in any direction.
a) tension, distortion
b) stress, fracture
c) stress, distortion
d) distortion, stress
c) stress, distortion
55
To overcome stress & distortion from restrained expansion and contraction you would
a) use a joint design that reduces amt of weld metal required
b) use a sub assembly to make as many unrestrained welds as possible
c) try to design the weldment to have room for movements while they are hot and after cooling
d) all of the above
d) all of the above
56
When you know a weld is going to pull parts out of alignment what can you do to compensate for this?
preset the parts
57
Heating one area of a project so that the area needing to be welded expands open. Accepts the welds and then everything is allowed to cool results in:
a) very high residual stress
b) high residual stress
c) very low residual stress
d) low residual stress
c) very low residual stress
This process is referred to as dimensional upset
58
What are the 2 ways to preheat?
- local preheat (small surface area)
- total preheat ( entire structure)
- total used when structure requires slower controlled cooling
59
On the WPS when preheating is included it is usually specified as a __________
a) max temp
b) median temp
c) average temp
d) min temp
d) min temp
60
What 2 factors does preheating prevent?
High stress & cracking
61
Metals that are low in ________ or prone to cracking should always be preheated prior to any hot work.
a) tensile strength
b) malleability
c) thermal conductivity
d) ductility
d) ductility
62
Are the following steels low or high in ductility?
Cast iron:
High Carbon Steels:
Tool Steels:
Medium carbon alloy steels:
Cast Aluminum:
All are steels low in ductility
63
Does preheating prevent hardness?
Yes
64
The higher the carbon content requires __________ temps of preheat.
higher carbon content = higher preheat temps
65
Small welds on thick low carbon steel require a pre heat of
a) 100°F to 200°F
b) 125°F to 190°F
c) 150°F to 250°F
d) 175°F ro 225°F
c) 150°F to 250°F
66
Does preheating affect arc strikes?
Yes, preheat makes striking an arc much easier especially with bronze or Al electrodes
67
generally _________ slows the rate of cooling.
a) preheat
b) post heat
c) normalizing
d) both a & b
d) both a & b
both pre and post heat are used to slow the rate of cooling
68
does preheating affect the grain structure of the weldment and the surrounding metal?
Yes - preheating can also positively influence the mechanical properties of the weldment
69
What are the 4 effects preheating has:
reduces tensile strength
reduces residual hardness
increases ductility
increases the notch toughness
70
preheating slows the rate of cooling and enhances mechanical properties, the tendency for cracking is ____________.
a) reduced
b) reduced or eliminated
c) increases
d) increases exponentially
b) reduced or eliminated
71
Preheat temps normally range from
a) 100°F to 200F
b) 125°F to 190F
c) 150°F to 250°F
d) 100°F to 400°F
d) 100°F to 400°F Although they can be as high as 800°F for some alloy steels
72
Generally the higher alloy steels and higher carbon levels require (higher or lower) preheat temps?
higher alloy & carbon content = higher preheat temps
73
When might you avoid preheating?
a) using austenitic SS
b) quenched alloys
c) tempered alloys
d) all of the above
d) you might avoid preheating all: austenitic SS, quenched or tempered alloys.
Follow the WPS or check with a supervisor.
74
Postheating is adding heat _______ after welding
a) shortly after welding
b) immediately after welding
c) up to days after welding
d) any point after welding
b) immediately after welding
75
Are the following 2 statements true or false
-Post weld heat treatment takes place after welding but not immediately after.
- Stress relief is an example of a post weld heat treatment process that can take place days after the weld has cooled.
Both are true
76
What are the 4 main purposes of post heating welds on carbon steels
- slowing the cooling rate of the weld and HAZ
- prevent hydrogen induced cracking
- reduction or prevention of martensite
- relief of residual stress
77
Hydrogen induced cracking usually occurs ____
a) in the weldment
b) surrounding area of the weldment
c) the HAZ
d) a parallel area of the weldment outside the HAZ
c) the HAZ
78
Hydrogen induced cracking usually occurs
a) immediately after welding
b) shortly after welding
c) up to several weeks after welding
d) there is no time limit found for the cracking to be found present
c) up to several weeks after welding
79
How is hydrogen introduced to the weld nugget?
a) through the filler metal
b) through the shielding gas
c) through both the filler metal and shielding gas
d) is pulled from the base metal during welding
a) through the filler metal
80
__________ the weld right after completion allows the hydrogen to migrate out of the weld and reduce the chance of hydrogen induced cold cracking.
a) preheating
b) post heating
c) normalizing
d) annealing
b) post heating
81
________ is a grain structure that is needle like and is very hard and brittle.
b) martensite
82
Martensite is formed by:
If the steel is rapidly ________ it cools so quickly that the carbon does not have time to come out of solution.
quenched
83
Post heating slows the cooling rate and allows the ______ to escape to the grain boundary and not become trapped
a) hydrogen
b) manganese
c) iron
d) carbon
d) carbon
84
Slowing the rate of cooling reduces the
a) overall stress
b) internal grain structure
c) internal stresses
d) surface tension
c) internal stresses
85
Generally the higher the post heat temp the lower the ____________
a) residual tension
b) surface tension
c) internal stress
d) residual stress
d) residual stress
86
What are the 2 main factors for determining post heating temps of a weld.
material thickness
carbon and other alloy content
+ was the material heat treated when manufactured
87
True or False
Postweld heat treatments can be divided into two general categories.
True
Hight temp - above upper critical temps
Low temp - below the lower critical temp
88
What is another term for transformation temp?
a) UC - upper critical temp
b) LC - lower critical temp
b) LCT - lower critical temp
89
Facts to remember about heating and cooling rates
- dont weld steels <0°C or 32°F
- Thick steel that surrounds small arc welds at room temperature are colder quenches the weld faster than if it were quenched in water.
-Never quench hot steel unless you want to increase the hardness.
- Never attempt to weld such objects as automotive springs, spindles or other suspension or steering components. if it fails you may be liable for injury or death due to negligence
90
The change from one crystalline form to another is completed at a temp known as
a) UC - upper critical temp
b) LC - lower critical temp
c) transformation temp
a) UC - upper critical temp
91
True or False
Post weld heat treatments that involve the UC include:
- normalizing
- annealing
- hardening
True
92
True or False
Heat treating steels from specific temperatures is done to alter the grain structure and in turn affect the mechanical properties.
True
93
The main difference between normalizing, annealing & hardening is ________ at which they are cooled.
a) temps
b) time
c) rate
d) method
c) rate
94
_______ is sometimes done on welded steel structures to produce uniformity in grain structure throughout the weldment,
a) heat treating
b) normalizing
c) annealing
d) hardening
b) normalizing
95
_________: heating the entire structure to 50°-100°F - higher than the UC. Held at that temp for 1hr/inch of thickness. then allowed to cool in still air at room temp
a) heat treating
b) normalizing
c) annealing
d) hardening
b) normalizing
96
This process consists of heating the weld area well back from the weld on both sides to above the upper critical temperature and then allowing the area to cool in still air.
a) heat treating
b) local normalizing
c) full annealing
d) hardening through
b) local normalizing
97
__________is the process of softening a material or bringing it to its softest, toughest, weakest state.
a) heat treating
b) local normalizing
c) full annealing (annealing)
d) hardening through
c) full annealing (annealing)
98
___________ brings the temp up to about 100°F. Higher than UC, held for 1hr/1" of cross section thickness. Cooled in a furnace for controlled very slow temp reduction
a) heat treating
b) normalizing
c) annealing
d) hardening
c) annealing
A heated object could be buried in slaked lime, dry ashes or hot, dry sand to slow the cooling rate even further
99
The 4 main purposes of annealing:
* soften the steel so that it can be more readily formed or cold worked.
* aid in machining,
* refine the grain structure and
* remove residual stresses.
100
What is considered to be the hardenable range of carbon content?
a) .1-.30%
b) .2-.35%
c) .3-.35%
d) .4-.30%
c) .3-.35%
101
Steels containing ≥ 0.35% carbon must be treated with caution in cooling otherwise ____ occurs
a) cracking
b) deformation
c) hardening
d) stress
c) hardening
102
The 2 main factors that influence the desired degree of hardness
steel composition - carbon content
improper quenching medium
103
Typical quenching media in order of severity are
a) brine, iced water, oil, air blast, normal still air
b) brine, water, oil, air blast, normal circulating air
c) brine, water, oil, air blast, normal still air
d) iced brine, water, oil, air blast, normal still air
d) iced brine, water, oil, air blast, normal still air
104
________ is denser than all other quenching media and therefore cools steel the fastest
a) iced brine
b) water
c) oil
d) air blast
e) normal still air
a) iced brine
105
What are the 2 high temp hardening processes?
Flame & induction
106
Flame hardening means the hardening of the _______ surface without hardening the ________ material
a) outside, inside
b) inside outside
c) flame hardening always hardens the entire piece
d) flame hardening always only hardens the surface
a) outside, inside
107
What is another term for flame hardening
case hardening - it occurs with steels over .35% carbon
108
The process consists of applying very rapid and shallow heat, usually with an oxyfuel multi-flame, followed by and often preceded by a water quench.
a) tempering
b) flame hardening/case hardening
c) induction hardening
d) convection hardening
b) flame hardening/case hardening
109
True or False
Flame hardening is used on
sprocket and gear teeth
rail ends
bearing races and cones
engine valve train components
All use the flame hardening process
110
Induction hardening is another process used extensively for _________
a) tempering
b) flame hardening/case hardening
c) induction hardening
d) convection hardening
b) flame hardening/case hardening
111
The ______ hardening process can yield an exact degree of hardness to a specified depth.
a) tempering
b) flame hardening/case hardening
c) induction hardening
d) convection hardening
c) induction hardening
112
2 post weld heat treatments that involve temps below the LC (lower critical temp)
a) stress relieving
b) tempering
c) convection hardening
d) both a & b
d) both a & b
113
Stress relieving and tempering treatments dont alter the grain structure because the temps are kept
a) below the LC
b) above the UC
c) kept at a constant temp
d) allowed to slow cool
a) below the LC
114
Stress relieving removes stresses from welded and severely ______ objects. The process consists of a slow, controlled heating, preferably of the entire body
a) hardened
b) hot drawn
c) cold worked
c) cold worked
115
Stress relieving is done to the entire body of the fabrication between
a) 1000°F - 1500°F
b) 1100°F - 1300°F
c) 1200°F - 1300°F
d) 1300°F - 1500°F
b) 1100°F - 1300°F
116
What is a term to describing holding a material at a temperature for a specific period of time?
soaked
117
When _______the material is held (soaked) at 1100°F - 1300°F temperature for a period of 1 hour for each 25.4 mm (1") of thickness for mild steel.
a) stress relieving
b) tempering
c) convection hardening
d) both a & b
a) stress relieving
118
When stress relieving the temp always _______the LC
a) above
b) greatly above
c) below
d) greatly below
c) below
119
In stress relieving generally:
the rate of cooling = the rate of heating
true or false
true
120
Because the material is kept below the l_______ temperature range, there is no change to the crystalline structure or to the grain structure, so the mechanical properties are generally unaffected by this heat treatment.
a) UC
b) LC
b) LC
121
___________ is a heat treating process that reduces hardness and promotes toughness.
a) annealing
b) preheating
c) post heating
d) tempering
d) tempering
122
Tempering reduces internal stresses, so it increases the _______ of the object.
a) conformability
b) ductility
c) toughness
d) hardness
c) toughness
123
Tempering temps used typically range from (425°F) to (600°F) but can be as high as just below the lower critical.
This is usually followed by a liquid quench that halts the withdrawal of _______.
a) conformability
b) ductility
c) toughness
d) hardness
d) hardness
124
What 2 processes are described below
1. The steel is hardened by heating it above the upper critical temperature and
_______ it.
2. The steel is then _________ by heating to a predetermined temperature which is below the lower critical temperature and then quenching is done again.
quenching & tempering
125
Polished steel undergoes color changes.
match the colours with their descriptions
Purple, light straw yellow, dark blue
450°F uses: cutters, drill bits, boring tools
555°F uses: centre punches and drifts
600°F uses: wrenches
450°F - Light straw yellow
555°F - Purple
600°F - Dark Blue
126
What are 3 temperature indicating devices useful in welding?
Temp indicating crayons and pellets
pyrometers
thermocouples
127
Temperature indicating pellets are avail for temps up to:
a) 500°F
b) 1200°F
c) 1500°F
d) 2200°F
d) 2200°F
128
__________ provides a continuous indication of the material's temperature and is useful for all postweld heat treatments.
a) pyrometers
b) thermocouple
c) berometer
d) temp crayons/pellets
b Thermocouples can be wired to a gauge, so the temperature can be read.
Or they can be interfaced with a computer that records the temperature on paper for a permanent record of the heat treatment process.
129
What is required to harden steel? (22)
* an annealing process
* stress relieving process
* a carbon content below 0.30 percent
* a carbon content above 0.35 percent
a carbon content above 0.35 percent
130
When does post heating takes place?(16)
* after the weld has cooler
* immediately after welding
* directly before putting the cover pass on
* during the welding process to maintain heat input
immediately after welding
131
Transition expansion occurs when a metal changes from: (9)
* grey to red
* a solid to a liquid state
* one crystalline form to another
* a cryogenic to a room temperature
one crystalline form to another
132
External surface hardening of steel could be referred to as what type of hardening. (24)
* ore
* top
* case
* core
case
133
What effect does quenching have on medium carbon steels: (23)
* reduces hardness
* increases ductility
* increases hardness
* increases malleability
increases hardness
134
Which metal is considered to have the highest degree of thermal conductivity? (7)
* brass
* steel
* copper
* aluminum
copper
135
The procedure for welding an automotive spring would include: (18)
* not attempting to weld the spring
* preheat to approximately 200 degrees F, then weld and insulate
* preheat below the lower critical temperature and proceed to weld
* preheat to the upper critical temperature and then proceed to weld
not attempting to weld the spring
136
Which of the following gases produces the most BTU's per cubic foot? (6)
* propane
* acetylene
* propylene
* natural gas
propane
137
Which of the following fuel gases would be the most efficient for heating purposes? (6)
* gas
* propane
* acetylene
* natural gas
propane
138
Conduction is the: (7)
* ability of heat to travel on light waves
* ability of a material to transfer heat within itself
* ability of a material to radiate heat from the surface
* rate of expansion as heat is being externally applied
ability of a material to transfer heat within itself
139
Heat transmitted from a hot object to another object is referred to as: (7)
* convection
* conduction
* transmission
* all of the above
convection
140
Heat treatment of a joint, in the lower critical temperature zone, followed by a slow controlled rate of cooling, is known as: (27)
* stress relieving
* normalizing
* tempering
* hardening
stress relieving
141
What would be the result of welding a joint where both expansion and contraction were restrained? (11)
* stress in the joint
* excessive warping
* a good sound weld
* the metal will expand but not contract
stress in the joint
142
A fine grain structure: (4)
* is creating by welding a joint in a single pass
* leaves columnar grains in the weld metal
* increases tensile and yield strength
* all of the above
increases tensile and yield strength
143
Tempering is described as a: (28)
case hardening process
* toughening process
* preheating process
* hardening process
toughening process
144
Metals that are low in ductility, should be preheated to: (15)
* improve arc starting
* promote fine grain size
* reduce or prevent stress
* improve the hardenability
reduce or prevent stress
145
What is the purpose of post heating?(16)
* prevents hydrogen induced cracking
* reduces martensite formation
* relieves residual stress
* all of the above
all of the above
146
Multi-pass welding results in what type of grain structure? (3)
* fine
* coarse
* grain structure that does not change
* refined weld but coarse HAZ
fine
147
Which mechanical properties are true of a finer grain structure?(4)
* higher tensile strength
* higher yield strength
* increased hardness
* all of the above
all of the above
148
Temperatures used for post heating welds depend on the material thicknesses. (17)
True
False
True
149
Flame hardening is accomplished by: (24)
* rapid heating and slow cooling
* slow heating and slow cooling
* rapid heating and water quench
* heating in a gas furnace and allow to cool in still air
rapid heating and water quench
150
The minimum percentage of carbon required for hardening of steels is: (22)
* 0.06 percent
* 0.20 percent
* 0.35 percent
* 2.4 percent
0.35 percent
151
Worn or broken steering parts on motor vehicles must be repaired by: (18)
* replacing with new manufactured parts
* preheat and post weld heat treatment must be done
* weld with a specified electrode then quench the part
* weld the part with low hydrogen electrodes and slowly cool
replacing with new manufactured parts
152
A low temperature heat treatment followed by a liquid quench, would be referred to as: (28)
* stress relieving
* normalizing
* tempering
* annealing
tempering
153
How would you change the temperature of a neutral flame when gas welding? (6)
* open oxygen needle valve slightly
* close oxygen needle valve slightly
* close acetylene needle valve slightly
* temperature of a neutral flame can't be changed
temperature of a neutral flame can't be changed
154
Which heat treatment will bring steel to its softest, toughest, weakest state: (21)
* tempering
* annealing
* normalizing
* stress relieving
annealing
155
Which of the following will affect the heat affected zone (HAZ) of a weld? (2)
* size of electrode
* amperage setting
* welding process
* all of the above
all of the above
156
Which heat treat process requires the steel to be cooled very slowly. (21)
* annealing
* hardening
* normalizing
* all of the above
annealing
157
When heat is transferred from one body to another it is called: (7)
* radiation
* transference
* convection
* conduction
convection
158
During the annealing process, the recommended cooling method is: (21)
* in oil
* in air
* in water
* in insulation
in insulation
159
A thermocouple will provide: (33)
* a continuous reading of a materials temperature
* a permanent record of heat treatment
* postweld heat treatments
* all of the above
* all of the above
160
When metal is heated and allowed to cool slowly in air, what would be the result? (10)
* internal cracking
* dimensional upset
* surface hardening
* it will remain the same after cooling
it will remain the same after cooling
161
Post weld heat treatment and post heating are the same procedure. (16)
True
False
False
162
Pieces of metal placed on either side of the joint to absorb the heat of the weld are referred to as: (8)
* rollers
* clamps
* chill strips
* weld positioners
chill strips
163
Local normalizing, recommends cooling: (21)
* in oil
* in water
* in still air
* in a furnace
in still air
164
In which instance should preheating be avoided? (15)
* when welding high carbon steels
* when welding austenitic stainless steel
* when working in cold ambient temperatures
* when welding thick sections of aluminum with GMAW
* when welding austenitic stainless steel
165
The flame temperature of acetylene is higher than the flame temperature of propane. (6)
True
False
True
166
Which fuel gas is most beneficial for welding and cutting?(6)
* propane
* acetylene
* propylene
* natural gas
acetylene
167
Which of the following is a temperature sensitive device: (32)
* temperature indicating pellets
* thermocouple
* pyrometer
* all of the above
all of the above
168
Dimensional upset could prove to be, an advantage when: (12)
*removing broken studs
* using jigs and fixtures
* removing excess reinforcement
* welding around the neutral axis
removing broken studs
