Ceramic slurry is used in making the molds for

Low permeability molds and low pouring temperature of the molten metal causes ......................... defect in castings.

Pressure die casting deals with casting metals of relatively ............. A ............. melting point and provides ........ B.......... production rate.

A. higher / lower,$$\,\,\,\,\,\,\,\,\,\,$$ B. higher / lower

A rectangular block of steel $$C.S$$ $$100\,\, \times \,\,150mm$$ and $$250mm$$ height is to be cast with out any riser. The block is moulded entirely in the drag of a green sand flask & is tap gated. The cope of the flask is $$200mm$$ height & the height of the metal during pouring is $$100mm$$ above the cope level. A tapered sprue is employed & the gating ratio is $$1:4:2$$. Assume no energy losses in the system. The time taken (in seconds) to fill the casting cavity, if the tapered sprues with $$500$$ $$m{m^2}$$ exit area is used.