Lecture 4 Flashcards
What is the other name of permanent mold casting?
Gravity die casting
In permanent mold casting, what is the mold made of if steel or iron is to be casted?
Graphite
Permanent mold life depends on:
- Alloy being cast
- Mold material
- Pouring temperature
- Mold temperature
- Mold configuration (thickness variation)
What are the types of permanent mold casting?
- Tilt-pour
- Low Pressure
- Vaccum (cleaner metals than low pressure)
What differentiates die casting from permanent mold casting?
In die casting, the metal is injected under high pressure. This causes turbulence leading to high porosity and other surface defects.
What are the types of die casting?
- Hot chamber (Gooseneck)
2. Cold chamber (aluminum/magnesium)
Does rheocasting and thixocasting contain superheat?
No
What shape will have the inner surface of a vertically rotated centrifugal casting?
Parabolic
What are the different melting methods?
- Cupolas (alternating layers of carbon, iron, limestone and alloy additions)
- Indirect fuel-fired furnace (heated crucibles)
- Direct fuel-fired furnace (flame is over metal)
- Arc furnaces (preferred method for factories, fluxes added)
- Induction furnaces (high and low frequency)
What is a ladle?
They are used to transfer metal from the furnace to the mold.
What is a benefit of automating casting processes?
Safety is increased.
Can sand cores be used for die casting?
No, because of the pressure involved.
What is impregnation?
Filling surface porosity voids with resin.
What is infiltration?
Filling surface porosity voids with lower melting point metals.
