annealing for steels

spherodizing, normalizing, full annealing, process annealing, and stress relief

In annealing you heat the material to a very high temperature (In case of Steel above the upper transformation temperature), hold it and then slowly cool it in the furnace atmosphere itself. This makes the grain size coarse.

Contrary to this, in normalizing you heat the ferrous material (as it is only applicable to ferrous materials) and remove it from furnace and let it cool in the air. So the material becomes hard. The reason for this being you get a much refined fine grain structure.

Annealing and Sintering are the same processes.

Full annealing process consists of three steps. First step is heating the steel component to above upper critical temperature by 30 to 50 deg c, after suffciant soaking time parts will be cooled very slowly in the furnace. Where as for ISo Thermal annealing parts will be heated above upper critical temperature by 30 to 50 deg c, after suffciant soaking time parts will be transfered to intermediate temprature( Below the lower critical temperature) and allow to equalise the temperature then cool in air to Room temperature