Q1: Annealing of a material does not

ANS:C - case harden it.

Annealing of a material does not "case harden it." Annealing is a heat treatment process used to soften a material, relieve internal stresses, and improve its machinability, ductility, and toughness. During annealing, the material is heated to a specific temperature (above its recrystallization temperature for metals) and then slowly cooled, often in a controlled manner. The purpose of annealing is to alter the microstructure of the material, typically by promoting the formation of new, equiaxed grains that are free from defects and dislocations. This process leads to a reduction in hardness and an increase in ductility, making the material easier to work with and less prone to fracture. Case hardening, on the other hand, is a different heat treatment process used to increase the surface hardness of a material while maintaining a tough and ductile core. It involves adding carbon or nitrogen to the surface of the material through processes such as carburizing or nitriding, followed by heat treatment to diffuse these elements into the surface layers, forming a hardened case. Therefore, annealing does not case harden a material. Instead, it softens the material and makes it more ductile and machinable.