18 Questions
What casting process involves rotating the mold at high speed so that centrifugal force distributes the molten metal to the outer regions of the die cavity?
True centrifugal casting
In which type of casting is the outside shape of the casting round, octagonal, or hexagonal, while the inside shape is theoretically perfectly round?
Centrifugal casting
What type of part is typically produced using open centrifugal casting?
Pipes
Which casting process involves pouring molten metal into a rotating mold to produce tubular parts?
Centrifuge casting
What is the name of the rule that provides a mold constant for calculating total solidification time in certain casting processes?
Chvorinov's Rule
In the context of total solidification time, what effect can a higher mold constant have on the casting process?
Increase the solidification time
Why are the walls of a permanent mold kept thick?
To increase the flow of molten metal
In sand casting, how does the fluidity of molten metal change?
Increases with an increase in thermal conductivity of the mold
What is the role of pouring temperature in fluidity of molten metal?
Increases fluidity
How does total solidification time change with rapid cooling?
Decreases total solidification time
Which type of casting process involves pouring molten metal into a mold and allowing it to solidify before removing the part?
Permanent mold casting
What is a characteristic feature of open die casting?
Involves intricate and detailed molds
What is the purpose of heating the one-piece mold further in the casting process described?
To facilitate the removal of water and wax
In which type of casting are two halves of a mold made from materials with high erosion and thermal fatigue resistance?
Open die casting
What is used to produce castings with internal cavities in permanent-mold casting?
Metal or sand aggregate cores
Which material is the mold cavity typically coated with to increase the life of permanent molds?
Sodium silicate and clay slurry
At what temperature are molds heated in permanent-mold casting to facilitate metal flow and reduce thermal damage to dies?
150° to 200°C
Which of the following materials is NOT commonly used in permanent-mold casting?
Bronze
Study Notes
Centrifugal Casting
- Centrifugal casting involves rotating the mold at high speed to distribute molten metal to the outer regions of the die cavity using centrifugal force.
- This process produces castings with round, octagonal, or hexagonal outside shapes and theoretically perfectly round inside shapes.
- Typically, open centrifugal casting produces tubular parts.
Total Solidification Time
- Chvorinov's rule provides a mold constant for calculating total solidification time in certain casting processes.
- A higher mold constant can increase the total solidification time, affecting the casting process.
Permanent Mold Casting
- Thick walls are maintained in permanent molds to prevent thermal damage.
- In this process, the fluidity of molten metal decreases with increasing pouring temperature.
- Rapid cooling decreases the total solidification time.
- The mold is heated to facilitate metal flow and reduce thermal damage to dies, typically at a temperature of 150-200°C.
- The mold cavity is typically coated with a ceramic material to increase the life of permanent molds.
Other Casting Processes
- Open die casting involves pouring molten metal into a mold and allowing it to solidify before removing the part.
- A characteristic feature of open die casting is the formation of a free surface on the part.
- Heating the one-piece mold further is used to improve the casting process.
- Sand casting is a type of casting process where the fluidity of molten metal changes drastically.
- Core materials are used to produce castings with internal cavities in permanent-mold casting.
- Copper and graphite are materials used in permanent-mold casting, but not titanium.
Calculate the time required for molten metal to solidify in a casting process. Learn about the classification of casting processes and the importance of mold design. Test your knowledge on metal casting techniques.
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