impact test vs. material normalization

Not sure what it is you are asking in your question. If the material you selected does not meet the minimum design metal temperature (MDMT), you typically need to select a more suitable material to meet this temperature. Impact testing is used to assure material compliance for a selected MDMT. Normalization is a heat treatment process that results in specific mechanical properties - typically slightly higher strength with lower elongation and reduced toughness over annealing or sub-critical annealing heat treatment.

Fine grain practice refers to materials that are cast and treated during solidification to produce a fine grain structure. Material is orginally ordered in this manner. Typically, fine grained steels have improved toughness and are used for low temperature applications.

If you can re-state your question, it might help to get the answer you need.