Solution heat treatment is a metallurgical process where alloys are heated to a temperature where one of the components becomes a solution while the other remains a solid and then is quickly cooled-off before the solution has precipitated. This process is conducted in a solution furnace that manufacturers build for use in industries that manufacture auto parts, cylinder heads and pistons, aluminum sheets, aluminum ingots, aluminum conductors, aluminum foils, and so on.
The Structure
Solution furnace manufacturers often build these furnaces with a drop bottom and a furnace that is supported by an elevated structure underneath which there is a cooling pit that contains the cooling liquid. This way, once the heating is done, the metal can be dropped immediately into the cooling pit for quick cooling.
These furnaces are either circular or rectangular in shape and with an insulated cover that is attached to a hydraulic or electrochemical system that moves the cover. The cover can be opened in order to feed the charge into the furnace with the aid of a hydraulic or electrical mechanism that lifts and lowers the charge into the furnace.
The loading platform, along with the quenching tank, is placed on a trolley that may be driven either hydraulically or electrically. This is done above ground-level and permits the quenching of the heated charge in less than thirty seconds. The loading trolley moves under the furnace to lift and drop the charge for the required heating and subsequent soaking purposes. If the quenching time required is longer than thirty seconds, then a quenching tank can be mounted underneath the furnace while the loading platform moves with the trolley, loading and unloading the charge into the furnace.
There is a hot air recirculation fan inside it that makes it possible to rotate the air inside by a centrifugal or axial fan. The fan could be equipped with a two-speed motor or a VVF (Variable Voltage Frequency) Drive. The furnaces typically have two walls that are insulated with a ceramic fiber blanket, placed in between the two walls. This also helps minimize wall loss.
Fuel Source
The energy source for these furnaces can be either electricity or the use of other combustible fuels. In electrically fueled furnaces, there are resistance wires located on the walls of the furnace and are divided into heating zones that can be controlled separately. Both types of furnaces come with their own set of safety devices that prevent any accidents from happening while the furnace and the combustion system are in operation.
Safety Tips
For the safety of the operators who work on the furnace and others around it, solution furnace manufacturers always recommend that the air inside it should never accumulate as this may lead to an explosion.
The process of lighting up a flame should be conducted under controlled circumstances only and in the right order of sequence. The gas pressure should be within the accepted range for the type of furnace and procedure in question. It should be maintained above the minimum level but below the maximum limit throughout the procedure.
All smoke alarms, flame detectors, temperature sensors, and carbon monoxide detectors must be regularly checked to see if they are working. This is will help in case of a potential gas leak or a carbon monoxide leakage which could be extremely dangerous.
The process of heat treatment leaves the charge in an unstable state due to the rapid heating and cooling process it must undergo during the treatment. Therefore, it is necessary that it is handled with all the safety and precaution methods kept in mind to avoid any preventable accidents from occurring.
