Pick out the wrong statement ?

A. Addition of methane to the furnace atmosphere reduces decarburising by hydrogen
B. Nitrogen in presence of steam decor-burises high carbon steel, whereas hydrocarbon gases
carburise the surface of steel at annealing temperatures
C. Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation
with increase in surface hardness
D. None of these

Related Mcqs:

Which of the following variables affects the furnace capacity ?
A. Temperature of flue gas
B. Thermal conductivity of stock
C. Thickness of heating stock
D. All A., B. and C.
Furnace aerodynamics is related to the _____________ in the furnace?
A. Movement of gases
B. Measurement of flue gas volume
C. Temperature control
D. Pressure adjustment
Hearth furnaces are not used for____________________?
A. Roasting
B. Melting
C. Reheating
D. None of these
Which of the following is not a directly fired furnace ?
A. By-product coke oven
B. Calcination kiln
C. Sintering furnace
D. Open hearth furnace
Thermal efficiency of furnaces can be improved by____________________?
A. Waste heat recovery from flue gas
B. Minimising heat losses from furnace walls
C. Maintaining proper draught
D. All A., B. and C.
In low or standard frequency induction furnace, heat is produced by the_______________________?
A. Combination of induced current and skin effect
B. Induction and resistance
C. Current flow through a heating element
D. None of these
Which of the following advantages is not associated with the use of preheated air for combustion of a fuel in the furnace ?
A. Increase in calorific value of the fuel
B. Increase in flame temperature
C. Reduction in scale losses
D. Saving in fuel consumption
Which is a regenerative furnace ?
A. Coke oven heating chamber
B. Open hearth furnace
C. Both A. and B.
D. Neither A. nor B.
______________ is an indirectly heated furnace?
A. Open hearth furnace
B. Muffle furnace
C. Soaking pit
D. Reheating furnace
Turndown ratio of a burner gives an idea of the ______________ in the furnace?
A. Range of fuel firing rates
B. Volume of the combustion chamber
C. Maximum heat input rate only
D. Minimum heat input rate only