IK4-AZTERLAN and the company CIE LEGAZPI develop a heat treatment method that takes advantage of the residual heat of forged components in processes and plants with space limitations

The new development allows up to 75% energy savings in comparison with conventional heat treatment.

Heat treatment is a key manufacturing stage in a wide range of forged components. It permits controlling the mechanical properties and microstructure of the parts, both to ease their further processing and to achieve their final service condition. This process is highly energy consuming, since it usually requires the heating full batches of components from room temperature to the desired treatment temperature setpoint. In many occasions, it requires the use normalizing furnaces with temperatures of around 900ºC.

Because of its high energy consumption and due to the resources dedicated to the logistics, more efficient alternatives have been developed, such as controlled cooling or the application of in-line heat treatment after forge. In this last case, residual heat is exploited, and each piece is thermally treated as a unit, decreasing the heating and cooling time of each part and therefore, the overall time used in the manufacturing processes.

But this in-line heat treatment cannot always be applied, sometimes due to the geometry of the component, due to specific quality requirements or because of space and plant layout reasons. IK4-AZTERLAN and the company CIE LEGAZPI have developed an innovative in-line forging and heat treatment method when the main limitation is related to space issues. For that purpose, heat treatment diagrams and cooling curves that allow to calculate the cooling process and the optimal temperature that forged components must achieve before being introduced in the treatment furnace have been calculated.

The main key of this new process relays on a preliminary thermal conditioning of the components before being loaded into the annealing furnace. According to Mrs. Itziar Berriozabalgoitia, researcher at Forming Technologies research line of IK4-AZTERLAN, “the cooling process before annealing is needed to ensure that the desired hardness and machinability properties will be achieved”.

Among the different alternatives studied by the research team to achieve the mentioned previous cooling, a controlled immersion process in a medium for the thermal conditioning of steel has proven to be more effective than others. This method is the one that “provides the best final characteristics required for the component”.

The laboratory and pilot-plant scale tests performed have demonstrated that the new development allows to reach up to 75% energy savings in comparison with the conventional heat treatment method.

To apply this methodology a previous feasibility analysis must be performed taking into account the characteristics of the material and the part to be manufactured, as well as the characteristics of the plant, lay-out, production process, the production planning, size of the furnaces, … etc.

Collaboration within the EFFORT 4.0 project, funded by the Hazitek program

This innovation has been achieved within the EFFORT 4.0 project, funded by Basque Government’s Hazitek program. EFFORT 4.0 aims at developing an advanced sensor network and artificial intelligence to improve efficiency of forging and casting (GDC, HPDC, VHPDC) processes.

Lead by Alcorta Forging Group, the consortium of the project EFFORT 4.0 is formed by companies and innovation agents of the Basque Country from different working fields such as metallic transformation technologies, information management, energy efficiency and cybersecurity:  Ekide S. Coop., CIE-Legazpi, Larraioz, Ulma Embeded Solutions S. Coop., Dominion, AYS, Ingetek, Ceiber, Titanium Industrial Security, Mondragon Unibertsitatea, IK4-Ikerlan, AC4C, Vicomtech, Ikergune, Deusto University and IK4-AZTERLAN Metallurgy Research Centre.

Forged components in CIE LEGAZPI.