1-51.
Flame hardening produces a hard
case that resists wear and a tough
core that is unaffected by heat
treatment.
1.
True
2.
False
1-52.
The process of heating steel to a
1-53.
1-54.
1-55.
1-56.
specific temperature (below its
hardening temperature), holding
this temperature for a certain
length of time, and then cooling
the steel in still air to room
temperature is known by what term?
1.
Annealing
2.
Hardening
3.
Tempering
4.
Case hardening
Steel can be tempered provided some
hardness remains after it has been
normalized.
1.
True
2.
False
The softness, ductility, and
resistance to impact are NOT
increased in which of the following
metals?
1.
Aluminum
2.
High-speed steel
3.
Low-carbon steel
4.
Already hardened steel
What are the most important
properties to be obtained in
tempering permanent steel magnets?
1.
Stability and malleability
2.
Softness and malleability
3.
Hardness and stability
4.
Ductility and resistance
to wear
When cooling a part in a quenching
medium, you should agitate the part
or the quenching medium for what
reason?
1.
To break up gases that form
2.
To induce oxidation
3.
To reduce the cooling rate
4.
To raise the temperature of
the liquid
1-57.
The flush method of quenching is
better than other quenching methods
for parts having cavities or
recesses for which of the following
reasons?
1.
It enables formation of gases
that enhance the hardening
process
2.
It enduces oxygen into the
process to increase the
temperature
3.
It ensures a thorough uniform
quench as liquid is sprayed all
over the parts
4.
It facilitates the formation
of gases that help reduce the
temperature
1-58.
When water is used as a quenching
medium, it should NOT exceed what
temperature?
1.
65°F
2.
75°F
3.
85°F
4.
95°F
1-59.
Of the following quenching mediums,
which one has the highest cooling
rate compared to water?
1.
Fuel oil
2.
Caustic soda
3.
Brine, 10% solution at 65°F
4.
Sodium hydroxide, 10% solution
1-60.
Which of the following is the
solution?
1.
3.8% salt for every 3 gallons
of water at 65°F
2.
3/4 pound of salt per gallon
of water at 65°F to 100°F
3.
20% salt solution for the
entire mix
4.
3/4 pound of salt per
100 gallons of water
1-61.
Caustic soda requires special
handling because of its harmful
effects on skin and clothing.
1.
True
2.
False
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