Permanent Mould Casting Flashcards
Why is the mold pre-heated in the mold preparation process?
To allow better metal flow and reduce defects.
What is applied to the mold cavity surfaces to facilitate part removal and increase mold lifetime?
A ceramic coating.
What materials are typically used to make cores for complex casting features?
Cores are typically made from iron or steel, but expendable sand cores may also be used.
How many castings can be manufactured from a mold depending on the alloy and casting complexity?
Between 100 to 250,000 castings.
What factors determine the selection of mold material?
Pouring temperature, size of the casting, and frequency of the casting cycle.
What material is most commonly used for casting due to its fine grain?
Fine-grained grey cast iron.
What materials are used for casting large volumes and large parts?
Alloy cast iron, C20 steel, and alloy steels.
For small-volume production from aluminum and magnesium, which type of molds can be used?
Graphite molds.
How does the die life change with higher melting temperature alloys?
Die life is shorter for higher melting temperature alloys such as copper or grey cast iron.
What process is called “semi-permanent molding”?
When sand cores are used in permanent mold casting.
Through what is molten metal poured into the mold?
Through a sprue at the top of the mold.
What happens after the molten metal solidifies in the mold?
The two mold halves are opened and the casting is removed.
What is the purpose of trimming in casting?
To cut away the excess material that solidified in the runner system and sprue during cooling.
What is the typical range of castings manufactured depending on the alloy and casting complexity?
Between 100 to 250,000 castings.
What factors influence the selection of material for casting?
Pouring temperature, size of the casting, and frequency of the casting cycle.
What is the most commonly used material for casting?
Fine-grained grey cast iron.
What materials are typically used for large volumes and large parts in casting?
Alloy cast iron, C20 steel, and alloy steels.
What type of molds may be used for small-volume production from aluminum and magnesium?
Graphite molds.
Why is the immediate withdrawal of the core important after solidification?
To prevent damage to the casting and ensure proper mold operation.
What can be included in a metallic mold to enhance its life?
A cooling system.
What is a refractory material coating, and what is its purpose?
A mixture of sodium silicate, kaolin clay, soapstone, and talc applied up to 0.8mm thick to enhance mold life.
What are the advantages of the casting process?
Produces fine-grained castings with superior mechanical properties.
Provides a very good surface finish.
Achieves closed dimensional tolerances.
Economical for large-scale production.
Produces small core holes compared to sand casting.
Allows for easy insertion of components.
How does die life vary with higher melting temperature alloys?
Die life is shorter for higher melting temperature alloys such as copper or grey cast iron.
What materials can cores be made from in permanent mold casting?
Cores can be made out of metal or sand.
