METAL CASTING PROCESS
1 State any four types of patterns.
Ans: The various types of patterns which are commonly used are as follows:
1) Single piece or solid pattern
2) Two piece or split pattern
3) Loose piece pattern
4) Cope and drag pattern
5) Gated pattern
2 Mention any two advantages and disadvantages of die casting. Ans: Advantages:
• It is a very fast process.
• Moulds have longer life.
• Better surface can be obtained.
• Moulds are much costlier.
• This method is not suitable for small quantity production.
• Shape and weight of the casting is limited.
3 Write the requirements of good pattern.
Ans: Simple in design
• Cheap and readily available
• Light in mass
• Surface id smooth
• Have high strength
4.What is core venting?
Ans: While pouring the mould with molten metal mould walls and cores heat up rapidly and releases large amount of gases. In order to prevent casting defects these gases must be vented out. For this purpose core venting are used. Core venting are incorporated in the core box itself.
5.What function of core ?
Ans: Functions of core are:
• Core provides a means of forming the main internal cavity for hollow casting.
• Core provides external undercut feature.
• Cores can be inserted to obtain deep recesses in the casting.
• Cores can be used to increase the strength of the mould.
6. Which process is called lost waxing method? Why?
Ans: Investment casting process is also known as Lost-wax process. The term investment refers to a clock or special covering apparel. In investment casting, the clock is a refractory mould which surrounds the precoated wax pattern.
7. What is the function of core prints?
1. Core prints are basically extra projections provided on the pattern.
2. They form core seats in the mould when pattern is embedded in the sand for mould making.
3. Core seats are provided to support all the types of cores.
4. Though the core prints are the part of pattern, they do not appear on the cast part.
8. What are the advantages and applications of ceramic moulds?
• It is less expensive
• Intricate objects can be casted.
• Castings of thin sections and which do not require machining can be produced.
• It is mainly used for all material using better ingredient in slurry.
9. What are the pattern materials?
10. Explain the term fettling.
Ans: Fettling is the name given to cover all those operations which help the casting to give a good appearance. It includes the removal of cores, sand, gates, risers, runners and other Unwanted projections from the casting.
11. What are the applications of casting?
Ans: Transportation vehicles (in automobile engine and tractors)
• Machine tool structures
• Turbine vanes and power generators
• Mill housing
• pump filter and valve
12. Mention the specific advantages of Co2 moulding Process.
1.Gives strength and hardness to core.
2.Process cost is less.
3.It saves time on heating.
4.It can be stored for long use.
13. Define AFS grain- fineness number.
It is defined as the ratio between the total products and total percentage of sand retained on pan and each sieve.AFS grain fineness number =sum of products /total sum of the % of sand retained on pan and each sieve.
14. Classify moulding Machines.
3.Jolt – squeezer Machine.
5.Patten draw Machines.
15.what are the different types of furnaces used for casting.
1.Cupola Furnace. 2.Open Hearth furnace 3.Crucible Furnace. 4.Pot Furnace. 5.Electric Furnace.
16.State the main functions of tuyeres in cupola furnace.
The tuyers are used to supply air to the coke bed for complete burning.