Full Annealing Service

Product Description

In fact, the actual definition of annealing describes only thefull annealing. That is, full annealing consists of heating the steel to atemperature at or near the critical point, holding there for a time period andthen allowing it to cool slowly in the furnace itself.

The main objects of full annealing are:

(i) To soften the metal,

(ii) To refine its crystalline structure, and

(iii) To relieve the stresses.

Material: Thefull annealing is specially adopted for steel castings and steel ingots:

process of FullAnnealing

In full annealing, hypoeutectoid steels (less than 0.77% C) areheated to 30 to 60C above the upper critical point i.e., A3 line (i.e.,between 723C and 910C). This is to convert the structure to homogeneoussingle-phase austenite of uniform composition and temperature, held at thistemperature for a period of time, and then slowly cooled to room temperature.

Cooling is usually done in the furnace itself by decreasing thetemperature 10 to 30C per hour to at least 30C below the A line. Then, thealloy is removed from the furnace and air cooled to room temperature.

Now the resulting structure is coarse pearlite with excessferrite. In this condition, the steel is quite soft and more ductile.