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ANNEALING PROCESS

What is the process of annealing ?

Annealing is a heat treatment process that affects the physical properties of materials to increase their ductility, eliminate stress and reduce their hardness.  Parts can be vacuum annealed or under controlled atmosphere

 

The parts must be heated above their recrystallization temperature. This encourages the creation of new grains and allows the reorientation of grains already formed. The metal’s internal stresses are reduced by the rearrangement and formation of grains, wich also improves the flow of the crystal structure.

Why doing an annealing treatment ?

The aim of the microstructure’s modification is to remove stress or modify properties such as hardness, strength or ductility in the crystalline structure of the material being annealed. 

The annealing process is also used to increase magnetic and electric conductivity of materials which made this process ideal for magnetic and electronic components. 

This process is often performed after a material has undergone a hardening or cold working process to prevent it from brittle failure or to make it more formable for subsequent operations.

The exact time and temperature depends on the material itself, on the amount of prior cold work, solute concentration, and type of the desired annealing treatment.

What are the three stages of annealing ?

Recovery stage :

During this phase, the part is heated to a temperature that must remain below the melting point. The temperature must be controlled to avoid large thermal variations which could induce internal stresses that could weaken the material’s structure and compromise its mechanical properties. 

This phase restores ductility and softens the material. 

Recrystallization stage :

During this stage, the temperature must reach the recrystallization temperature. As in the previous stage, the temperature must remain below the melting point. 

It is during this phase that the crystalline structure is reorganized, forming a new granular structure.  

This restores the material’s pre-treatment properties. 

Grain growth stage :

After these two steps, the material is cooled down. The cooling rate can vary according to the desired mechanical properties to be reached.  

There are two cooling techniques:  

  • Slow cooling: promotes the formation of a softer, more ductile crystalline structure.  
  • Fast cooling (quenching): used to obtain a harder, more resistant structure.  

What are the advantages of annealing ?

  • Soften a material and increase its machinability 
  • Increase the material hardness with a low temperature quenching 
  • Elimination of thermomechanical stresses 
  • Magnetic annealing restores the properties of pure iron after it has been altered by another treatment. 

Annealing furnaces by ecm lab solutions

ECM Lab Solutions vacuum annealing furnaces, are coming from the ECM Technologies range of products.  

ECM Lab Solutions vacuum furnaces are particularly well suited to research centers and laboratories and offer a wide choice of applications as : 

Cristal furnace

cristal : Vacuum bell furnace

High temperature vacuum heat treatment furnace.

Processes : Tempering, Degassing, Hyper-quench Hardening, Brazing, Sintering, Magnetic Annealing, Glass-to-Metal Sealing.

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Liliput furnace

Liliput : Hearth lift vacuum furnace

Allow high added value applications.

Processes : Brazing, Sintering, Glass-to-metal sealing, Annealing, Magnetic Annealing, Degassing.

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Turquoise furnace

Turquoise : Vacuum horizontal furnace

Specifically designed for oxidation-sensitive alloys such as nickel, titanium, chromium cobalt, molybdenum and tungsten.

Processes : Stress relieving, Annealing, Ageing, Solution treatment.

See more details on this furnace