What is MIM components normalizing? 

Normalizing: This process is to heat the steel parts to 30--50 degree more than the critical point of Ac3 (for hypoeutectoid steel) or Accm (hypereutectoid steel). After a proper holding temperature time, the parts cool down uniformly in the air.

Microstructure after normalizing: hypoeutectoid steel is F+S; eutectoid steel is S, hypereutectoid steel is S+Fe3CII. The main difference between normalizing and complete annealing is faster cooling rate, in order to normalize the structure of steel.

What is MIM parts annealing?

Annealing: Heating the hypoeutectoid steel workpiece to 20-40 degrees above than AC3 for a proper time and cooling slowly in the furnace (or buried in sand or lime) to below 500 degrees in air. It is a heat treatment process to normalize the steel structure.