Scabs may be caused by
A.low permeability of sand
B.high moisture content of sand
C.intermittent running of molten metal over the sand surface
D.any of the above
Category: Foundry Technology Mcqs
Which of the following operations improve wear resistance and mechanical properties of castings?
A.Shot peening
B.Chilling
C.Nitriding
D.All of the above
The function of riser is
A.to provide an opening through which molten metal is poured
B.to give an indication that mould is filled
C.to allow the heat of molten metal to dissipate to atmosphere
D.to supply molten metal to casting as it tends to contract during solidification
The amount of machining allowance on castings depends on
A.size and shape of the casting
B.casting orientation
C.characteristics of the metal
D.all of the above
The cross-section of a sprue
A.square
B.circular
C.rectangular
D.any of the above
A mould which has good erosion resistance to metal flow and is also collapsible is
A.green sand mould
B.skin dry sand mould
C.dry sand mould
D.none of the above
Cores are made from core sand mixed with the binder which may be
A.linseed oil
B.turpentine
C.cement
D.none of the above
Pattern draft for internal surfaces is (in mm/m)
A.10 — 30
B.40 – 70
C.50 – 80
If dross and slag along with the liquid metal reach the mould cavity they produce the defect known as_______________?
A. Misrun
B. Inclusions
C. Blow holes
D. All of the above
Slag and dross can be removed by ________________?
A.skimming from the molten metal
B.using bottom pouring ladle
C.using pouring basin in place of a pouring cup
D.any of the above
