ANNEALING

ANNEALING FOR NORMALISATION

The steel will be heated plus 20 – 40°C over Ac3 temperature ( transition temperature from ostenite-ferrite phase to completely ostenite phase) and then cooled in air. Thus ruined microstructure will be turned into normal condition with causing alfa -gamma transforming twice. In a high heating temperature and after long heating time microstrucre will have big grains. Cooling very slow causes to forming big grains, too

ANNEALING FOR SOFTENING

The purpose of this process is the making filingsly and unfilingsly machining easy with creating soft material. This process will be applied with heating the part over Ac1 (723°C) temperature or changing temperature up – down at this temperature level. The part must be cooled slowly.

ANNEALING FOR RELIEVING TENSILE

After casting, forging, and heat treatment because of differences of cooling that happened on section lengthwise, also because of welding and cold forming the part, it will be exposed to tension. Purpose of heating is the relieving this tensions. Heating will be done at temperatures between 550 – 650°C. The part must be cooled very slowly. That’s why the part will be cooled in oven.


Annealing for Diffusion

This process is applied for relieving the concentrate differences. Formation of crystal fibres will be relieved during heating for diffusion. Also it is observed to remove the dendirites with heating time increased. In this process, the part will be heated up to 1050 – 1300°C and holded much at this temperature depending on content of carbon.

Annealing for Enlargement of Grain

The purpose of this process is the enlarging the grains. Heating will be done at high temperature and cooling will be done slowly. Cooling can be gained speed a bit under Ac1 temperature.

Annealing for Recrystalisation

This process will be applied at the temperatures between 600 – 700°C. It will be done for changing the grains that ruined during rolling and forging, to stable condition. With increasing heating temperature, heating time becomes shorter. The part will be cooled in a normal period.