BILBAINA DE TRATAMIENTOS
The main purposes of the annealed steel are soften the material to work it better, regenerate its structure and eliminate internal tensions.
There are various types of annealing , which differ in maximum temperature at which the steel must be heated , the conditions of temperature maintenance , and cooling medium speed steel .
Considering the maximum temperature of heating, and subsequent controlled temperature swings during annealing treatment can be divided into regeneration subcritical annealed ( soft annealing , and annealing with stress relieving bitterness ) where heated to a temperature below the temperature critical, globular or spheroidization annealing and isothermal annealing
ANNEALING OF REGENERATION
Involves heating above the critical temperature to transform all austenite steel , after cooling it slowly to 500 ° C. Subsequently allowed to air cool . Obtained ferrite and pearlite or cementite and pearlite . It serves to soften the steel and regenerate their structure.
Its main purpose is to soften the steel for fast and Budget process involves heating process steel to a temperature that is lower to the criticism , this as close as possible , there is not a complete transformation to austenite and cool air piece .
Annealing against acrimony
Takes place at temperatures of 625 ° to 675 ° , and is intended primarily to increase the ductility of steels little carbon content (less than 0.4 dde . %) Frio.Con estrados in this temperature destroys elongated ferrite crystallization , appearing new polyhedral crystals allow more ductile stretching or rolling back the material without difficulty. The cooling is performed in air.
It is a treatment for tool steels , carbon or alloy weakly improves machinability. It is a compromise between the annealing process of regeneration and subcritical . It consists of an oscillating heating at temperatures slightly above and below the critical , followed by slow cooling . You get the lowest possible hardness with a microscopic structure favorable for the machining of parts. By this treatment it is achieved that the globular cementite adopt a structure for each composition having a hardness much lower than any other microstructure , including laminar pearlite .
is a softening treatment consisting of heating the steel above critical area , between 740 º and 820 º, then lowered to a temperature between 600 ° and 700 ° which remains constant for several hours to achieve complete transformation of austenite isothermal and finally cooled in air. Very low hardness are obtained .