Innovative heat treatments The Forge Fedriga’s TRR Island

Heat treatments are processes that give a metal alloy or metal a crystalline structure, such as specific technological or mechanical characteristics. Various types of heat treatment can be implemented for an alloy or metal. For example, tempering, stress relieving, solubilization, and normalizing. Another example of heat treatment can be annealing, which in turn can be distinguished into isothermal annealing, complete annealing, globularization annealing, workability annealing, and recrystallization annealing.

The Forge Fedriga’s heat treatment island

Forge Fedriga has made a major financial and strategic investment in its heat treatment island. Many factors led to this decision, motivated first and foremost by the need to count on a state-of-the-art management and technological plant. Therefore, a plant that is capable of ensuring high tolerances and excellent parameters, such as to guarantee maximum competitiveness in a highly competitive and very demanding market.

Plant structure

The plant includes an automatic loader and two methane furnaces, each with a capacity of 25 tons, located at the side. There is also a central water cooling tank of 350 cubic meters capacity supplemented by a tank agitation system. The activities carried out by the furnaces optimize the heat treatments and ensure that tolerances can be guaranteed at different temperatures optimally. In fact, one furnace is intended for tempering and stress relief treatments, while the other furnace is mainly used for austenitizing heat treatments, such as quenching and solubilization heat treatments.

The two furnaces

The austenitizing furnace can operate between 800 and 1200 degrees Celsius, and its dimensions are 6800 x 2500 x 1800 (h). On the other hand, the tempering furnace has an operating temperature ranging between 450 and 800 degrees Celsius. The dimensions are the same as the other furnace. The tempering furnace of the heat treatment island ensures cooling rates comparable to the air cooling ones, thanks to the presence of fans. This is the reason why normalizing can be performed.

The cooling tank

The dimensions of the cooling tank are 8400 x 8400 x 5000 (h). The temperature of the liquid before immersion is 30 degrees Celsius. In the tank, it has an average velocity of 0.5 to 0.75 meters per second. The tank has a capacity of 350 cubic meters for a charge to be submerged of 25 tons; water recirculation occurs thanks to two evaporation towers, as a result of which, during the entire cooling cycle, 40 degrees Celsius are not exceeded.

The water agitation system

Two modules make up the water agitation system. The first, located at the bottom of the tank, has a vertical vector while the second, intended for agitating pipes and drilled pieces, has a horizontal vector. On the opposite side are pumps whose task is to suck in the water and then return it to the cooling towers. It is possible to use the modules simultaneously or separately. For the first module, there are 37 agitators, and they ensure a recirculation of 26400 cubic meters per hour. The second module has 14 agitators and ensures a recirculation of 12000 cubic meters per hour.

Heat treatment island: the other elements

The rototranslating loader of the heat treatment island features a maximum load of 25 tons. It has six interchangeable forks, with a length of 2.6 meters and a width of 5.6 meters. An exciting feature of this device is its ability to rotate using adequate rotation speeds, both clockwise and counterclockwise. But there is more than just rotation since the loader can also translate vertically and horizontally. To accommodate the Norsok requirements, the time to exit the kiln and soak in water is less than 60 seconds.

Plant: checking and testing

Once the modules have been installed and the water has been filled, agitation checks are carried out to verify the values in the quenching area. The horizontal and vertical agitation checks are carried out with no submerged charge using an anemometer. The same check is then repeated with a hot submerged charge.