Burnout of casting to expand the mould is done at a temperature of: (A) 100 C, (B) 538 C, (C) 675-710 C, (D) None of the above
Answer is B. The burnout operation is done to

Dry the moisture out of the mould: The mould is heated at 212 F (100 C) for 1 hour to vapourize the moisture content in the investment.
Expand the mould to compensate for solidification shrinkage of the metal: The mould is heated at 1000 F (538 C) for 1 hour to complete mould expansion
Eliminate the pattern plastics and waxes by melting and vapourization: The mould is heated at 1250 to 1300 F (675 C to and 710 C) for 1 to 2 hours to eliminate and vapourize the traces of wax.