253. The sand is packed on pit moulds with
A.Manually
B.Squeezers
C.Jolt machines
D.Sand slingers
254. Sprue in casting refers to
A.Gate
B.Vertical passage
C.Riser
D.Horizontal passage
255. Pick up the incorrect statement about advantages of disposable patterns
A.Finish is uniform and reasonably smooth
B.No complex wooden pattern with loose piece pattern is required
C.No cores are required
D.Patterns can be handled easily and process is adaptable to mechanical moulding equipment
256. In cold chamber method of die casting
A.Only low melting point metals can be cast
B.High melting point metals can be cast
C.Die is kept hot by electrical heating
D.Die is kept cold by circulating water
257. Which of the following casting methods utilises wax pattern
A.Shell moulding
B.Plaster moulding
C.Slush casting
D.Investment casting
258. In slush casting process
A.Molten metal is fed into the cavity in metallic mould by gravity
B.Metal is poured into die cavity, and after a predetermined time the mould is inverted to permit a part of metal still in molten state to flow out of cavity
C.Cavity is filled with a precalculated quantity of metal and a core or plunger is inserted to force the metal into cavity
D.Metal is forced into mould under high pressure
259. In slush casting
A.Consumable patterns are used
B.Plunger is used to force molten metal to fill up cavities
C.Vacuum is applied to facilitate complete filling of casting
D.When a solid shell of sufficient thickness has formed, remaining liquid is poured out
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