Rossi Tre deals with performing heat treatments and surface treatments of metals and alloys. In today’s article we will explain in particular what is meant by annealing, one of the heat treatments that we perform in the company and we will explain its function.
When is the annealing done?
Annealing is performed to soften steel and make it easier to work mechanically, eliminating residual plastic stresses or canceling the effects that the alloy has undergone during hot working or a previous heat treatment.
In addition to steel, the annealing treatment can also be performed on cast iron, brass, bronze and some aluminum alloys.
Depending on the hardness and structure that you want to obtain, you have different cycles available.
What are the types of annealing?
Our company offers different types of Annealing for different metals and alloys, including:
- Subcritical and machinability annealing;
- Isothermal annealing;
- Relaxation annealing;
- Full annealing.
Machinability or subcritical annealing, what is it?
This type of annealing, among the most widespread, requires heating to a temperature of 35°c lower than ac1.
It does not substantially modify the microstructure of the steel, it can be considered as a softening tempering without any transformation from ferrite to austenite. Consequently, the final structure obtainable will be strictly linked to the starting one.
Subcritical machinability annealing is performed on construction and tempering steels, to which it gives good machinability by chip removal.
Isothermal annealing, what is it?
Isothermal annealing is a heat treatment that completely eliminates the stresses resulting from hot and cold plastic processing, significantly reduces the hardness of the material and homogenizes the existing microstructure.
The aim is to obtain maximum workability by chip removal and excellent dimensional stability that can be found even after final heat treatments such as carburizing or surface hardening.
At an industrial level, it is preferred to complete annealing because it is more convenient in terms of both time and resources.