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Test your basic knowledge |
Manufacturing Processes
Start Test
Study First
Subject
:
engineering
Instructions:
Answer 26 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Solidify in similar manner as pure metals; as pure metals freezing range approaches zero - the solidification front moves as a plane without forming a mushy zone. The type of structure developed after solidification depends on the composition of the
Shrinkage
Eutectics
Fluidity
Basic Steps of Casting
2. The law of mass continuity states that - for incompressible liquids and in a system with impermeable walls the rate of flow is constant. Q=Asub1vsub1 = Asub2vsub2 - Q= volume rate of flow (such as m^3/s) - A= cross sectional area of the liquid strea
Eutectics
Runners
Mass Continuity
Reynolds Number
3. Or short local solidification times - the structure becomes finer with smaller dendrite arm spacing.
Higher cooling rates (10^4 K/s)
Mushy Zone
Sprue Design
Gate
4. 1. Flow of molten metal into the mold cavity 2. Solidification and cooling of the metal in the mold 3. Influence of the type of mold material
Re Range
Eutectics
Risers (or feeders)
Important considerations in casting operations
5. Are the channels that carry the molten metal from the sprue into the mold cavity or connect the sprue to the gate.
Important considerations in casting operations
Mushy Zone
Metallic projections
Runners
6. 1.) Contraction of molten metal as it cools prior to solidification. 2.) Contraction of the metal during phase change from liquid to solid (latent heat of fusion). 3.) Contraction of the solidified metal (casting) as its temp. drops to ambient temp.
Important considerations in casting operations
Shrinkage
Mushy Zone
Reynolds Number
7. The design of a sprue must be tapered from top to bottom as long as the pressures are the same - Asub1/Asub2 = sqrt(hsub2/hsub1)
Sprue
Eutectics
Sprue Design
Basic Gravity Casting System
8. Defects consisting of fins - flash - or projections.
Metallic projections
Even higher cooling rates (10^6 to 10^8 K/s)
Reynolds Number
Mass Continuity
9. Serve as reservoirs of molten metal to supply any molten metal necessary to prevent porosity due to shrinkage during solidification.
Sprue
Risers (or feeders)
Sprue Design
Solidification Time
10. Atapered vertical channel through which the molten metal flows downward in the mold.
Sprue Design
Sprue
Gate
Even higher cooling rates (10^6 to 10^8 K/s)
11. 1.) Viscosity- varies by temp. 2.) Surface Tension - high surface tension reduces fluidity 3.) Inclusions - can have an adverse effect on fluidity 4.) Mold Design - design - dimensions of the sprue - runners - and risers all affect fluidity. 5.) Heat
Characteristics of molten metal
Higher cooling rates (10^4 K/s)
Mass Continuity
Solidification Time
12. The higher the Reynolds Number the greater the tendency for turbulent flow to occur. In a gating system Re ranges from 2 -000 to 20 -000. A value of up to 2 -000 represents Laminar flow.
Incomplete casting
Re Range
Porosity
Fluidity
13. The width of the mushy zone - in which both liquid and solid phases are present - is described in the terms of a temperature difference - known as the: freezing range = (TL - TS) - which is a time not a temp.
Basic Steps of Casting
Mushy Zone
Flow Characteristics
Important considerations in casting operations
14. The portion of the runner through which the molten metal enters the mold cavity.
Important considerations in casting operations
Metallic projections
Fluidity
Gate
15. Porous area of a casting caused by shrinkage - or dissolved gases - or both.
Solidification Time
Incomplete casting
Porosity
Important considerations in casting operations
16. Defects such as folds - laps - scars - adhering sand layers.
Defective surface
Metallic projections
Runners
Porosity
17. The capability of molten metal to fill mold cavaties. Consists of two basic factors: 1.) Characteristics of the molten metal 2.) Casting parameters
Re Range
Important considerations in casting operations
Characteristics of molten metal
Fluidity
18. Premature solidification - not enough metal poured.
Basic Steps of Casting
Solidification Time
Mass Continuity
Incomplete casting
19. The heat released or absorbed by a body during a change of state without change of temperature. The term most often refers to a phase transition - such as melting of ice or the boiling of water. Pure metals solidify at constant temperatures - After t
Latent Heat
Sprue
Solidification Time
Basic Steps of Casting
20. Re- it is used to quantify flow characteristics. It represents the ratio of the inertia to the viscous forces in fluid flow. Re= vDp/n v= velocity D= diameter of the channel p and n= viscosity and density of the liquid
Incomplete casting
Sprue
Metallic projections
Reynolds Number
21. The structures developed are amorphous ('without shape' - or non - crystalline solid is a solid that lacks the long- range order characteristic of a crystal). As the structures develop - the resulting grain sizes influence the properties of the casti
Even higher cooling rates (10^6 to 10^8 K/s)
Characteristics of molten metal
Important considerations in casting operations
Incomplete casting
22. Or long local solidification times result in coarse dendritic structures with large spacing between dendrite arms.
Latent Heat
Fluidity
Mass Continuity
Slow cooling rates (10^2 K/s)
23. Avoid turbulence in gating system - the flow is highly chaotic and can lead to aspiration. Laminar flow is ideal
Eutectics
Higher cooling rates (10^4 K/s)
Incomplete casting
Flow Characteristics
24. A function of the volume of a casting and it surface area (Chvorinov's rule) = C(volume/surface area)
Solidification Time
Shrinkage
Eutectics
Mushy Zone
25. 1. Pouring molten metal into a mold patterned after the part to be manufactured. 2. Allowing it to solidify 3. Removing the part from the mold
Important considerations in casting operations
Sprue Design
Runners
Basic Steps of Casting
26. 1. Pouring basin or cup - where the molten metal is poured. 2. Gating system - molten metal flows through gating system
Basic Gravity Casting System
Mushy Zone
Incomplete casting
Fluidity