Table of Contents
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify.
The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process.
Advantages of Metal Casting process
- Molten metal flows into ant small section in molten cavity, hence any complex shape can be easily produced.
- Practically any type of material can be casted.
- Due to small cooling rate from all directions, the properties of casting are same in all directions.
- Any size of casting can be produced like up to 200 tonnes.
- Heavy equipment like machine leads, ship’s propeller etc. can be cast easily in the required size rather than fabricating them by joining several small pieces.
Also read : Sand Mould Casting
Applications of metal casting
Casting process is used in various fields like
- Transport : Automobile, aerospace, railways and shipping
- Heavy Equipment : Construction, farming and mining
- Machine Tools : Machining, casting, plastics molding, forging, extrusion and forming
- Plant Machinery : Chemical, petroleum, paper, sugar, textile, steel and thermal plants
- Defense : Vehicles, artillery, munitions, storage and supporting equipment
- Electrical Equipment Machines : Motors, generators, pumps and compressors
- Household : Appliances, kitchen and gardening equipment, furniture and fittings
- Pattern is defined as a model or replica or model of an object to be cast.
- The type of pattern to be used for a particular casting depends upon many factors like design of casting, complexity of shape, number of casting required [bulk of casting], mould process, surface finish and accuracy.
Functions of the Pattern
- A pattern prepares a mold cavity for the purpose of making a casting.
- A pattern may contain projections known as core prints if the casting requires a core and need to be made hollow.
- Runner, gates, and risers used for feeding molten metal in the mold cavity may form a part of the pattern.
- Patterns properly made and having finished and smooth surfaces reduce casting defects.
- A properly constructed pattern minimizes the overall cost of the castings.
Few types of material can be used to make pattern using which will make the final casting.
Features of the Pattern material
- Easily worked, shaped and joined
- Light in weight
- Strong, hard and durable
- Resistant to wear and abrasion
- Resistant to corrosion, and to chemical reactions
- Dimensionally stable and unaffected by variations in temperature and humidity
- Available at low cost
Cheap, easily available, light, easiness in surfacing, preserving (by shellac coating), workable, ease in joining, fabrication
- Moisture effects, wear by sand abrasion, warp during forming, not for rough use.
- Must be properly dried/ seasoned, free from knots, straight grained
Egs. Burma teak, pine wood, mahogany, Sal, Deodar, Shisham, Walnut, Apple tree