In strip casting, which of the following statements is Incorrect:

1. The higher casting speed, v, the higher the strip temperature at exit

2. The thinner the belts, the higher the heat flux through the belts

3. The lower casting speed, v, the lower heat flux through the belts

4. The colder the water spray, the high the heat flux through the belts

The lower the casting speed (v) 

-

The lower heat flux through the belts

-

Is incorrect

Hot tear in casting develops due to:

1. Turbulent flow of liquid metal into the mold

2. High superheat

3. Low cooling rates after solidification

4. None of the above

Hot tear in casting is not due to turbulent flow, high superheat nor low cooling rates

Therefore the answer is 4

In Lost-foam Casting, the patterns are made the same size as the actual (final) component:

True or False

In Die Casting, a high cooling rate is obtained due to pressure feeding:

true or false

In Investment Casting, the wax patterns evaporate when in contact with the molten metal:

true or false

In Sand casting a poor surface finish is obtained due to mold walls constructed out of coarse sand grains:

true of false

Distortion upon welding in the welded part (shown below) will be increased by which one of the following "individual" modifications?

1. Increasing the welding velocity, v

2. Preheating the part prior to welding

3. Choosing a base metal with a larger modulus of elasticity, E

4. Choosing a weld metal with a smaller coefficient of thermal expansion, α

5. None of the above

In resistance seam welding, which of the following statements is correct:

1. The frequency of the AC current determines the size of each weld nugget

2. The weld current, I, determines the number of weld nuggets per unit length

3. The current flow time, t, affects the size of each weld nugget

4. The resistance of the electrode wheels has no effect on the heat input

5. The process efficiency (K value) is NOT affected by the surface condition of the mating sheets (such as oxide layers and contamination) 

In Laser Powder deposition, 

The heat flow along the solid-liquid interface is minimum at point "B"

True or False

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In Laser Powder deposition, 

The columnar grains spacing, λ, is larger for alloys with a larger freezing range.

True or False

[image]

In Laser Powder deposition, 

the temperature gradient, G, along the solid-liquid interface is minimum at point "A".

True or False

[image]

In Laser Powder deposition, 

The dendrite growth direction is majorly controlled by the profile (morphology) of the solid-liquid interface.

True or False

[image]

In a Selective Laser Melting (SLM) operation on a metal powder bed, the layer of thickness is doubled. Which (2) of the following individual modifications would most likely ensure a complete fusion through the layer?

1. D₂=2D₁

2. D₂=0.5D₁

3. P₂=0.5P₁

4. P₂=2P₁

(D is the laser spot size & P is the laser power)

D₂=0.5D₁

_&

P₂=2P₁

In the roll bonding operation, which metal(s) (clad or base) must be ductile at (room or operation) temperature?

The size of flash is friction is NOT affected by which of the following:

1. rotational speeds, ω

2. thermal expansion coefficient, α, of the two metals

3. the yield strength of metals

4. upset length

The thermal expansion coefficient, α, of the two metals

does NOT affect in size of Flash 

in friction welding.

P₂=2P₁