Which defect may be caused by low strength and low hardness of the mould?

Which defect may be caused by low strength and low hardness of the mould?

a. Blow holes
b. Gases in metal
c. Drop
d. None of the above

Correct Answer : c. Drop

Explanation :

Drop casting occurs when a portion of sand drops down from upper portion of sand mould into the molten metal. This is due to low strength and low hardness of the mould.