Q1: Normalising of a casting does not

ANS:A - induce stresses in it.

When we mention that normalizing does not "induce stresses in it" regarding a casting, it means that the normalizing process itself doesn't introduce additional internal stresses into the casting. Here's a more detailed explanation:

1. Internal Stresses in Castings: Castings often contain internal stresses due to various factors such as uneven cooling rates during solidification, thermal gradients, residual stresses from the casting process, and phase transformations within the material. These internal stresses can lead to dimensional instability, distortion, or even cracking in the casting.
2. Normalizing Process: Normalizing involves heating the casting to a temperature above its critical temperature (the temperature at which its microstructure undergoes transformation) and then allowing it to cool in still air. This process is designed to refine the grain structure and relieve internal stresses within the casting.
3. Stress Relief: During the normalizing process, the casting is heated uniformly, which allows the internal stresses to relax gradually as the material reaches a uniform temperature throughout its cross-section. As the casting cools, the formation of a finer and more uniform grain structure helps to redistribute the internal stresses, leading to a more homogeneous and stable microstructure.
4. Result: The normalizing process, therefore, does not introduce additional stresses into the casting. Instead, it aims to relieve existing internal stresses, promote grain refinement, and improve the overall mechanical properties and dimensional stability of the casting.