UT2 Flashcards
A manufacturing process based on plastic flow is:
A) welding
B) casting
C) forging
D) all of the above
C) FORGING
Describe plastic flow:
Deformation of a material that remains rigid under stresses of less than a certain intensity but behaves under severe stresses
A definite break in a material caused by excessive working of the metal during this forging, rolling or extruding operation:
A) cold shut
B) seam
C) burst
D) hot tear
C) BURST
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
À) HOT TEAR
An advantage of investment casting over green sand casting is:
A) reusable mold
B) larger parts may be cast
C) more complex shapes may be used
D) the need for cores never arises
C) more COMPLEX SHAPES
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) a shell mold casting
B) investment casting
C) permanent mold casting
D) none of the above
D) NONE of the above
An inherent defect formed during the plastic stage of solidification is:
A) burst
B) shrinkage
C) cold shut
D) hot tear
D) HOT TEAR
In gas welding, the acetylene is usually burned with:
A) oxygen
B) hydrogen
C) argon
D) nitrogen
À) oxygen
When are copper electrodes used in welding?
Spot/Seam welding
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
A non-consumable electrode used for arc welding would be made of:
A) tungsten
B) steel
C) copper
D) any of the above
À) tungsten
Another term for investment casting is the:
A) die casting method
B) lost wax process
C) semi-centrifugal process
D) none of the above
B) lost wax process
A metal forming operational 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
What is the sprues position of a mold?
Vertical runner
List the following in order from top to bottom on a mold:
A) Cheeks
B) Cope
C) Drag
Cope - cheeks - drag
Which of the following results from inclusions in the original cast material which are flattened out in the direction of rolling, forging, extruding?
A) laminations
B) stringers
C) blow holes
D) laps
B) STRINGERS
What is an amorphous solid?
Solidified but doesn’t take crystalline structure, more like a very viscous liquid.
Crystalline solids have a specific crystal structure called a ‘lattice’. What are the 3 main lattice structures?
- Body centered cubic (BCC)
- Face centered cubic (FCC)
- Hexagonal closed packed (HCP)
Metals that are body centered cubic have what two important properties?
Give two examples.
Hard and strong.
Ex. Iron, tungsten
What is the main property of a metal that solidified with a face centered cubic?
Give 3 examples.
Ductile.
Ex. Aluminum, copper, lead
Metals that solidify under hexagonal closed packed lattice structure are susceptible to what?
Give 2 examples.
Work hardening.
Ex. Zinc, magnesium
What is tensile strength?
The max stress that can be applied by pulling or stretching the material prior to fracture
What is yield strength?
The ability of a material that is deformed to return to original shape once load is removed
