120102d Heat Treatment Flashcards
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) the rate of cooling.
d) all of the above.
d) all of the above.
Which of the listed heat treatments alters the grain structure of the weld deposit and heat-affected zone?
a) stress relief
b) tempering
c) normalizing
d) preheating
c) normalizing
Temperature refers to the:
a) intensity of heat.
b) amount of heat.
c) volume of heat.
d) quality of heat.
a) intensity of heat.
The movement of heat within the body of a material is called:
a) radiation.
b) conduction.
c) convection.
d) transference.
b) conduction.
The transfer of heat from one body to another is called:
a) radiation.
b) conduction.
c) convection.
d) transference.
c) convection.
The movement of heat in air is called:
a) radiation.
b) conduction.
c) convection.
d) transference.
a) radiation.
The rate of thermal conductivity refers to the:
a) melting temperature of a metal.
b) BTU output of an oxyfuel welding tip.
c) speed at which heat travels within a material.
d) time required to melt through the metal.
c) speed at which heat travels within a material.
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) mild steel.
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) aluminum.
Restrained expansion of metal when it is heated results in:
a) internal cracking.
b) dimensional upset.
c) internal stress.
d) surface hardening.
b) dimensional upset.
Unrestrained expansion and contraction of a metal when it is heated and allowed to cool slowly produces:
a) internal cracking.
b) dimensional upset.
c) no appreciable change.
d) surface hardening.
c) no appreciable change.
The dimensional upset that occurs when expansion is restrained may be used to good advantage to:
a) remove broken studs.
b) use jigs and fixtures.
c) remove excess weld reinforcement.
d) weld around the neutral axis.
a) remove broken studs.
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) a good sound weld
c) very high stress
On which of the following jobs would expansion and contraction work in your favour?
a) when welding a joint subject to a high degree of restraint
b) when repairing an exhaust manifold
c) when repairing the spoke on a flywheel
d) when welding aluminum tire rims
c) when repairing the spoke on a flywheel
- 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) prevent weld bead cracking.
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 stresses.
b) slow the quench rate.
Which of the following cannot be accomplished with a postweld heat treatment?
a) annealing
b) normalizing
c) stress relieving
d) distortion control
d) distortion control
What is the soaking time required to stress relieve a steel weldment that is one inch thick?
a) 1 hour
b) 2 hours
c) 3 hours
d) 4 hours
a) 1 hour
The annealing of a steel fabrication should:
a) decrease distortion.
b) increase hardness.
c) decrease ductility.
d) decrease tensile strength.
d) decrease tensile strength.
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) It decreases tensile strength and increases ductility.
d) It decreases tensile strength and increases ductility.
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) annealing.
Heating steel above its upper critical temperature and cooling in still air describes a heat treatment known as:
a) annealing.
b) normalizing.
e) stress relieving.
d) tempering.
b) normalizing.
The temperature range lor stress relieving is:
a) 870°C (1600°F) to 980”(1800°F).
b) 760°C (I400°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).
c) 595°C (1100°F) to 700°C (1300°F).
Tempering is a _____________ process.
a) case-hardening
b) preheating
c) hardening
d) toughening
d) toughening
To produce grain structure uniformity throughout the weldment and critical areas, you would:
a) temper.
b) stress relieve.
c) normalize.
d) preheat.
c) normalize.
Heating above the upper critical temperature followed by a rapid quench describes:
a) stress relieving.
b) normalizing.
c) tempering.
d) hardening.
d) hardening.
Heating below the lower critical temperature followed by a rapid quench describes:
a) stress relieving.
b) normalizing.
c) tempering.
d) annealing.
c) tempering.
A temperature-indicating crayon marked at 150°C (300°F) is used for:
a) hardening.
b) preheating.
c) stress relieving.
d) annealing.
b) preheating.
Which of the following is a temperature-sensing device?
a) thermograph
b) inclinometer
c) barometer
d) pyrometer
d) pyrometer
