Different types of cooling process
Cooling is becoming increasingly important in connection with the heat treatment of products. Essentially, a distinction is made here between two different types of cooling:
Cooling as quickly as possible, predominantly without tolerance, for further handling or further processing of the products/materials
Targeted, controlled cooling in a relatively narrow temperature tolerance field to achieve desired product properties or to avoid material stresses in sensitive products/materials
Given below are some selected practical examples to illustrate this process.
The cooling of different products as a follow-up process to the heat treatment in our industrial furnaces or after independent processes, must be designed similarly to heating across the surface and the appropriate heat transfer value. Here, the temperature difference, i.e. the difference between the cooling medium and the temperature of the products to be cooled, as well as the inflow velocity, play a significant role. For example, the cooling time can be adjusted via the inflow velocity of the cooling medium onto the product, especially when the temperature difference is decreasing.
For some processes, slow cooling or even cooling controlled by several temperature ramps is required to bring the workpieces to the core temperature equalisation (relaxation).
Here, cooling is usually carried out by means of different temperatures over a longer period of time, i.e. over hours or days.
Similarly, when tempering plastic parts, for example, it is necessary to maintain the product temperature at approx. 50 °C for a period of less than one hour even after the tempering process, before the products are cooled to temperatures for packaging or for subsequent work steps, so that they can be handled safely by persons without risk of burns or further protective measures, for example.
The cooling medium, usually process air, can be pre-tempered with cooling water to achieve reproducible cooling rates (summer/winter).
In order to prevent condensate from forming at these process air temperatures, these cooling zone housings must be suitably insulated to prevent them from falling below the dew point.
In other processes, in turn, quenching processes with very low cooling rates of up to 2-3 K/s at temperatures of 530 °C to 200 °C are necessary, for example, to freeze structural changes in the component.
For quenching processes, especially for the heat treatment of aluminium castings, quenching in tempered water or in polymer solutions is common, but especially for the “milder” quenching of what are referred to as structural components, which are increasingly used in automotive engineering, also with air. For these quenching processes, air discharge speeds are sometimes required beyond a speed of 100 Km/h, which are correspondingly generated by fans. In addition, especially with these generally large-volume components, a cooling as uniform as possible, i.e. homogeneous, must be ensured by means of an appropriate technology. As a side-effect, a very effective air technology can also save production space, as the cooling area can be reduced to almost a third of that of conventional cooling processes.
Cooling: a process which represents a challenge and which is implemented and handled reliably and efficiently by the Airtec technology.
Material properties according to customer requirements
The customer product, i.e. the targeted achievement of the material properties desired by the customer, is the focus of every heat treatment process. This is a central component of the actions of the entire Airtec team. Based on the specific product requirements, our engineers and technicians develop tailor-made process solutions and, together with our specialists, convert these into modern and energy-efficient industrial furnace and cooling technology, or a combination of both. In this way, system solutions are created from the cross-industry wealth of experience, from which our customers benefit to the full extent. Implementation examples can be found on our product sub-pages
If you have further questions about the processes of our heat treatment or cooling plants, please do not hesitate to contact us. We will be happy to advise you.