GATE Mechanical Engineering (ME) 2019 Shift 1 Solved Paper

Tiny gas bubbles are called porosities, but larger gas bubbles are called blowholes or blisters.
Such defects can be caused by air entrained in the melt, steam or smoke from the casting sand, or other gasses from the melt or mold. This is caused by poor permeability
A misrun occurs when the liquid metal does not completely fill the mold cavity, leaving an unfilled portion. This is caused by insufficient fluidity
Hot tears is the metallurgical defect. This happens because the metal is weak when it is hot and the residual stresses in the material can cause the casting to fail as it cools. This is caused by poor collapsibility
Wash is the casting defect of areas of excess metal. These appear when the molten metal erodes the molding sand.