Chemistry - Metallurgy Question with Solution | TestHub
Find the number of CORRECT statements for the given processes.
(i) Process of heating steel to redness and then cooling it very slowly, is knowns as annealing.
(ii) Process of heating steel in presence of NH3 and producing hard coating of Iron Nitride on the surface of steel, is knowns as nitriding.
(iii) Process of heating steel to redness and then cooling it suddenly by plunging it into water or oil, is knowns as quenching.
(iv) Process of heating quenched steel to a temperature well below redness and then cooling it slowly, is knowns as tempering
Answer:
Solution:
Annealing (i): Heating steel to redness and cooling it slowly increases its ductility.
Nitriding (ii): Heating steel with NH₃ forms a hard layer of iron nitride on the surface.
Quenching (iii): Heating to redness and plunging into water or oil cools it rapidly to increase hardness.
Tempering (iv): Reheating quenched steel below redness and cooling it slowly reduces brittleness.
