Question

Match the Column-I with Column-II :

(p) Nitriding	(I) Process of heating steel to redness and then cooling it very slowly
(Q)Annealing	(II) Process of heating steel in presence of $N{H}_3$ and producing hard coating of Iron Oxide on the surface of steel
(R) Tempering	(II) Process of heating steel to redness and then cooling it suddenly by plunging it into water or oil.
(S) Quenching	(IV) Process of heating quenched steel to a temperature well below redness and then cooling it slowly

Answer 1

Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface. These processes are most commonly used on low-carbon, low-alloy steels.

Annealing is also a heat treatment process that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. In this process, the metal is heated and then made to cool down slowly.

Tempering a heat treatment technique for ferrous alloys, to achieve greater toughness by decreasing the hardness of the alloy. It is a process for producing tempered glass. In this, the metal is heated below its clinical temperature and made to cool down suddenly.

Quenching is the rapid cooling of a workpiece to obtain certain material properties.