Materials & Processes Flashcards
As hot working progresses (assuming the temperature of the part is held constant), the energy required for further processing:
a. increases.
b. decreases.
c. remain constant.
d. any of the above may be true, depending on the material.
a. increases.
A fatigue crack is a service defect that is caused by:
a. cyclic loading of the part above the yield strength of the material.
b. cyclic loading of the part below the yield strength of the material.
c. local overheating of the part.
d. corrosive atmosphere.
b. cyclic loading of the part below the yield strength of the material.
The middle portion of a molding flask is called a:
a. cope.
b. drag.
c. cheek.
d. separator.
c. cheek.
A cause of gas porosity in welds is:
a. welding at too low temperature.
b. improper cleaning or preheating.
c. the use of insufficient filler metal.
d. restriction of movement of the material.
b. improper cleaning or preheating.
In the resistance welding process:
a. two parts to be joined are heated then pressure is applied
b. the pieces to be joined are held firmly together under pressure, followed by the generation of heat at the interface.
c. no heat is applied and the parts are welded by applying pressure only.
d. the parts are heated but not melted and a filler metal is added.
b. the pieces to be joined are held firmly together under pressure, followed by the generation of heat at the interface.
In a mold, the runner connects:
a. the pouring basin to the sprue.
b. the downgate to the riser.
c. the sprue to the ingate.
d. the pouring basin to the mold cavity.
c. the sprue to the ingate.
Metal forming during rolling results in:
a. plastic flow of the metal.
b. elongation of existing defects perpendicular to the rolling direction.
c. directional properties which are always beneficial for secondary forming operations.
d. the flattening out of defects which makes them more easily detectable by most N.D.T. methods.
c. directional properties which are always beneficial for secondary forming operations.
A welding defect that occurs at the root and runs parallel with the weld is:
a. a lack of fusion between beads.
b. an icicle.
c. a crater crack.
d. a lack of penetration.
d. a lack of penetration.
Hot working an ingot may produce a product with:
a. fewer defects than in the original ingot.
b. more defects than in the original ingot.
c. the same number of defects as in the original ingot.
d. any of the above may be correct depending on the circumstances.
d. any of the above may be correct depending on the circumstances.
A disadvantage of dry sand molds when compared to green sand molds is that:
a. erosion of the mold is more common.
b. castings are more susceptible to hot tears.
c. a surface finish is generally worse.
d. the overall dimensional accuracy is worse.
a. erosion of the mold is more common.
A long defect, parallel to the longitudinal axis of a bar and caused by blowholes, cracks or tears introduced in earlier processing and elongated in the direction of rolling or forging is called a:
a. seam.
b. forging lap.
c. lamination.
d. cold shut.
a. seam.
Rapid oxidation of metal surfaces during hot working of a mild steel may:
a. produce a carburized surface layer.
b. produce a product which is thicker than originally intended.
c. adversely affect the cooling rate of the newly formed material.
d. adversely affect the application of some non-destructive tests.
d. adversely affect the application of some non-destructive tests.
An advantage of shell molding compared to green sand molding is:
a. that larger castings can be produced when using shell molds.
b. the lower cost of production of shell molding.
c. a better surface finish is obtainable.
d. All of the above.
c. a better surface finish is obtainable.
A burst is an/a _______________________ discontinuity.
a. inherent
b. processing
c. service
d. All of the above.
b. processing
Bursts usually have the following characteristics, they:
a. appear as smooth indentations on metal surfaces.
b. are cavities varying in size from wide open to very tight, usually parallel with the grain.
c. are extremely thin and flat, generally aligned parallel to the work surface of the material.
d. are three dimensional discontinuities having smooth internal surfaces and generally located close to the surface of the wrought material.
d. are three dimensional discontinuities having smooth internal surfaces and generally located close to the surface of the wrought material.
In a rolling mill, flattening and elongation of metal is accomplished primarily by:
a. tensile stresses.
b. bending stresses.
c. compressive stresses.
d. high frequency cyclic loads.
c. compressive stresses.
The fuel gas most commonly used in gas welding is:
a. Butane.
b. Propane
c. Acetylene.
d. All of the above.
c. Acetylene.
Cold shuts are most likely to be found in:
a. extrusions.
b. forging.
c. castings.
d. sintered parts.
c. castings.
Air craft turbine blades are usually processed by:
a. investment casting.
b. shell mold casting.
c. green sand casting.
d. dry sand casting.
a. investment casting.
The electrodes used for spot welding are usually made of:
a. Carbon.
b. Mild steel.
c. Tungsten.
d. Copper.
d. Copper.
A metal forming operation which allows three dimensional control over the shape of the product is:
a. Rolling.
b. Extruding.
c. Forging.
d. All of the above.
c. Forging.
A forming operation which results in the greatest dimensional accuracy is:
a. Cold rolling of sheet.
b. Hot rolling of sheet.
c. Cold rolling of bars.
d. Forging.
d. Forging.
In which of the following joining methods will flaws essentially be two dimensional?
a. Gas tungsten arc welding.
b. Gas metal arc welding.
c. Submerged arc welding.
d. Brazing.
d. Brazing.
A flaw which can resemble a cold shut is:
a. an undercut in a weld.
b. a hot tear in a casting.
c. a blowhole in a casting.
d. a forging lap.
d. a forging lap.
Elements may be added to the filler metal to:
a. control grain growth.
b. increase ductility.
c. assure adequate corrosion resistance.
d. any of the above.
d. any of the above.
One of the main causes of cold shuts is:
a. improper preheating of molds.
b. the presence of several sprues or gates in the mold.
c. pouring without a filter.
d. the alloy selection.
b. the presence of several sprues or gates in the mold.
An EDM notch formed in 304 stainless steel may cause:
a. a local increase in permeability.
b. the formation of austenite around the notch.
c. an increase in conductivity.
d. all of the above.
c. an increase in conductivity.
CHECK FOR CORRECTNESS
Which discontinuity is not normally found in a casting?
a. Misrun.
b. Porosity.
c. Shrinkage.
d. Slugging.
d. Slugging.
Non-metallic impurities trapped within the molten metal of a casting are generally called:
a. blowholes.
b. inclusions.
c. cracks.
d. shrink cavities.
b. inclusions.
Most manufacturing defects in a tube are:
a. axial in direction.
b. circumferential in direction.
c. on the outside of the tube.
d. subsurface.
a. axial in direction.
Increasing test sample temperature normally:
a. increases electrical resistivity.
b. decreases electrical resistivity.
c. does not change electrical resistivity.
d. increases magnetic permeability.
a. increases electrical resistivity.
When thick and thin casting sections are adjacent to each other, what discontinuity may result?
a. porosity.
b. inclusions.
c. shrinkage.
d. core shift.
c. shrinkage.
Heat exchanger tubes are defect prone at regions:
a. adjacent to support plates.
b. under support plates.
c. in-between support plates.
d. all of the above.
d. all of the above.
Which of the following discontinuities is not normally associated with casting?
a. segregation.
b. core shift.
c. misrun.
d. bursts.
d. bursts.
Which of the following is identified as a casting insert?
a. chaplet.
b. mold.
c. gate.
d. riser.
a. chaplet.
The work metal used for working with a forging hammer is:
a. a bloom.
b. a billet.
c. a bar.
d. any of the above.
d. any of the above.
Cold working steel or aluminum results in a decrease in:
a. ductility.
b. hardness.
c. strength.
d. all of the above.
a. ductility.
The grain size of a ferrous metal is commonly refined by:
a. elastic deformation.
b. heat treatment.
c. high frequency mechanical vibrations.
d. both a and b.
b. heat treatment.
A method commonly used to remove a number of flaws in an ingot prior to forming is:
a. cropping.
b. heat treating.
c. welding.
d. sand blasting.
a. cropping.
Which of the following factors can have a negative influence on some non-destructive tests?
a. grain size.
b. grain orientation.
c. grain boundary composition.
d. all of the above.
d. all of the above.
The principle purpose of risers in molds is to:
a. feed the castings as the metal shrinks.
b. let air escape from the mold.
c. ensure impurities will remain outside the casting.
d. favour directional solidification.
a. feed the castings as the metal shrinks.
The process in which a mold is formed from a mixture of sand and a thermosetting resin binder that is placed against a heated metal pattern is called:
a. Dry sand molding.
b. Permanent mold casting.
c. Investment casting.
d. Shell molding.
d. Shell molding.
A casting process in which the pattern is not re-usable is called:
a. Shell mold casting
b. Investment casting
c. Sand casting
d. Composite mold casting
b. Investment casting
A casting process involving a re-usable mold is called:
a. investment casting.
b. shell mold casting.
c. dry sand casting.
d. die casting.
d. die casting.
Which of the following welding processes does not involve melting of the parts to be joined?
a. Arc welding
b. Gas welding
c. Pressure welding
d. Electron beam welding
c. Pressure welding
In the shielded metal-arc welding process, the electrode covering may include materials used to:
a. protect the metal from oxidation during melting and transfer across the arc.
b. protect the weld bead as it solidifies and cools to room temperature.
c. alloy the weld metal.
d. all of the above.
d. all of the above.
A non-consumable electrode used for arc welding would be made of:
a. Tungsten
b. Steel
c. Copper
d. Titanium
a. Tungsten
In gas welding, acetylene is usually burned with which other gas?
a. Oxygen.
b. Hydrogen.
c. Argon.
d. Nitrogen.
a. Oxygen.
Which of the following statements is correct?
a. The heat affected zone of a weld is basically a homogenous structure
b. In some areas of the weld heat affected zone, grain size can be smaller than in the unaffected base metal
c. The temperature in the heat affected zone can sometimes exceed the temperature in the fusion zone
d. Transverse cracks do not occur in the heat affected zone
a. The heat affected zone of a weld is basically a homogenous structure
A rupture in the material that can be in any direction on the part and is caused by localized stresses that exceed the tensile strength of the material is:
a. A fatigue crack
b. A heat treat crack
c. A seam
d. A stringer
a. A fatigue crack
CHECK FOR CORRECTNESS
A manufacturing process based on plastic flow is:
a. Welding.
b. Casting.
c. Forging.
d. All of the above.
d. All of the above.
A definite break in the material caused by excessive working of the metal during the forging, rolling or extruding operation is called a:
a. Cold shut
b. Seam
c. Burst
d. Hot tear
c. Burst
Improper cleaning or preheating of a weldment, or moisture on the base of the filler metal could cause:
a. Crater cracks
b. Porosity
c. Undercutting
d. Lack of penetration
b. Porosity
An inherent defect formed prior to completion of solidification of the casting because of restricted contraction is called a:
a. Hot tear
b. Shrinkage
c. Burst
d. Cold shut
a. Hot tear
CHECK FOR CORRECTNESS
An extremely thin discontinuity that is the result of pipes or inclusions flattened and made directional by working is called:
a. a stringer.
b. a lamination.
c. a seam.
d. a cold shut.
b. a lamination.
A surface defect caused by cyclical loading of a part below the yield strength of the material is called:
a. Intergranular corrosion
b. A heat treat crack
c. A fatigue crack
d. A hot tear
c. A fatigue crack
A cold shut is an inherent defect that may be caused by:
a. gases given off during casting and trapped in the metal.
b. not enough metal available to fill the mold.
c. too low a temperature of the metal poured.
d. the more rapid cooling of thin sections that adjoin heavier masses of metal which are slower to cool.
d. the more rapid cooling of thin sections that adjoin heavier masses of metal which are slower to cool.
An advantage of investment casting over green sand casting is:
a. The mold in reusable
b. Larger parts my be cast
c. More complex shapes may be cast
d. The need for cores never arises
c. More complex shapes may be cast
The material used for making a pattern depends on:
a. The type of material that will be cast
b. The grain structure desired in the finished casting
c. The expected production quantity
d. All of the above
d. All of the above
A green sand mold is:
a. a sand mold coated with a green wash.
b. a sand mold mixture made up of sand, clay and water.
c. a sand mold not yet ready for casting.
d. a sand mold used in the production of cores only.
b. a sand mold mixture made up of sand, clay and water.
In which of the following casting processes are cores never used?
a. Shell mold casting
b. Investment casting
c. Permanent mold casting
d. None of the above
b. Investment casting
The essential difference between permanent mold casting and die casting is:
a. In the first method, molten metal enters the mold by gravity, while the second method, the molten metal enters the mold under pressure
b. The mold in the permanent mold casting is reusable while it is not in the case of die casting
c. The mold in permanent mold casting is made of ceramic while steel is used to make the mold for die casting
d. There are no differences. Both names are used to identify the same process
a. In the first method, molten metal enters the mold by gravity, while the second method, the molten metal enters the mold under pressure
When metal solidifies:
a. Atoms become more mobile thus allowing them to migrate to definite positions within a crystal
b. Atoms lose mobility and assume fixed positions in the space lattice of the unit cell
c. A curie point is reached were crystals begin to grow
d. A curie point is reached where grain boundaries begin to form
b. Atoms lose mobility and assume fixed positions in the space lattice of the unit cell
After solidification, the structure of the outside surface of a casting usually consists of:
a. A mixture of large and small grains having random orientation and shape
b. Coarse columnar grains
c. Coarse equiaxed grains
d. Fine equiaxed grains having random orientation and shape
d. Fine equiaxed grains having random orientation and shape
What type of grain structure would normally be found at the centre of a heavy walled casting?
a. Fine equiaxed grains of random orientation and shape
b. Columnar grains with a dendritic structure
c. Large equiaxed grains with superior metallurgical characteristics
d. None of the above are correct
b. Columnar grains with a dendritic structure
In fusion welding, preheating will result in:
a. A reduced grain size
b. A harder structure
c. A reduced cooling rate
d. An austenitization of the base metal prior to welding
c. A reduced cooling rate
Elements may be added to the filler metal to:
a. control grain growth.
b. increase ductility.
c. assure adequate corrosion resistance.
d. all of the above.
d. all of the above.
An advantage of electroslag welding, over other methods of welding, is that:
a. A coarse grain structure is formed because of the slow cooling rate
b. It does not require special edge preparation on the base metal sections
c. Weld cracking is never a problem because of the absence of residual stress
d. Very thick sections can be welded easily
b. It does not require special edge preparation on the base metal sections
A difference between shielded metal-arc welding and gas metal-arc welding is that, in gas metal-arc welding:
a. The electrode is consumable
b. The shielding gas is contained in the flux covering the electrode
c. A stream of protective gas is passed through an inverted cup or a nozzle which surrounds the electrode
d. A slag coating is formed to protect the weld as it cools
c. A stream of protective gas is passed through an inverted cup or a nozzle which surrounds the electrode
Submerged arc welding may be performed:
a. In the flat position
b. In the flat and horizontal positions
c. In the vertical position
d. All of the above
d. All of the above
Arc welding is usually performed using:
a. Alternating current, low voltage and low amperage
b. Direct current, low voltage and high amperage
c. Direct current, high voltage and low amperage
d. Alternating current, high voltage and low amperage
b. Direct current, low voltage and high amperage
Hot tears in a casting may be the result of:
a. Interrupted or too slow metal pouring
b. Excessive gas in the metal poured
c. Insufficient metal poured
d. Improper use of chills
d. Improper use of chills
Laminations are produced:
a. When forging with faulty dies
b. When excess metal is folded over during a rolling operation
c. When a pipe or blisters present in the original ingot are made directional by rolling
d. When blowholes introduced in earlier processing are elongated, by extruding, in the direction of working
c. When a pipe or blisters present in the original ingot are made directional by rolling
A metal production process which eliminates the need for ingot cropping is:
a. Continuous hot rolling
b. Super hot rolling
c. Super hot extrusion
d. Continuous casting
d. Continuous casting
Inserts which may be found in sand molds are:
a. Chills
b. Chaplets
c. Cores
d. All of the above
d. All of the above
The first step in the production of casting is the making of:
a. A mold
b. A pattern
c. A core
d. A cavity
b. A pattern
A joining process which occurs without fusion of the base metal is:
a. Arc welding
b. Brazing
c. Spot Welding
d. Gas welding
b. Brazing
In which of the following welding processes is filler metal never added?
a. Brazing
b. Soldering
c. Arc welding
d. Spot welding
d. Spot welding
A type of defect which propagates along grain boundaries is called:
a. A fatigue crack
b. A transgranular crack
c. A borderline crack
d. A hot tear
b. A transgranular crack
Which of the following is a discontinuity that might be found in a forging?
a. Shrinkage cracks
b. Laps
c. Hot tears
d. Insufficient penetration
b. Laps
A weld defect formed as a result of shrinkage is called:
a. Undercutting
b. Heat affected zone cracking
c. A crater crack
d. An incomplete sidewall fusion
a. Undercutting
CHECK FOR CORRECTNESS
A steel casting suitable for working or remelting is called
a. A bloom
b. A billet
c. An ingot
d. A slab
b. A billet
With a forging hammer, the striking force is imposed on the work metal by:
a. The lower die only
b. The upper die only
c. Both dies moving in opposite directions
d. Both b and c
b. The upper die only
The factor which must be considered prior to selecting the hammer or press to produce a closed-die forging is:
a. The size of the forging
b. The production quantity
c. The design of the forging
d. All of the above
d. All of the above
Which of the following statements is correct?
a. The hardness of the dies for open-die forging is generally higher than the hardness of impression dies for closed-die forging
b. The hardness of dies for open-die forging is generally lower than the hardness of impression dies for closed-die forging
c. The life of dies for open-die forging is less than that of impression dies for closed-die forging
d. Both b and c are true
d. Both b and c are true