1. Purpose of the equipment. Technological processes used in the equipment.
The recirculating thermal heating unit “ARTN-6.5” is designed for hardening, annealing and aging of sheets, profiles and other parts made of aluminum alloys in an air environment.
The unit is a chamber electric resistance furnace in which heat is released as a result of the passage of current through conductors with active resistance.
Forced circulation of the atmosphere in the chamber makes complex heat exchange with heat transfer by radiation and convection. Therefore, high temperature uniformity is created in the working space of the furnace.

Hardening gives the product hardness and wear resistance. The metal is heated, held for some time, and then quickly cooled.
Annealing facilitates subsequent processing of the metal product. The workpiece is heated and then slowly cooled at room temperature.
Aging changes the internal structure of the metal. After aging, the metal's hardness and strength increase, but its toughness and ductility decrease.
The hardened product is heated and maintained at an high temperature and then cooled in air (artificial aging).

2. Features of the physical processes used.
During heat treatment, the metal is first heated to a certain temperature, maintained in this state for some time, and then cooled. How long the metal is heated and how quickly it cools directly determines its future physical properties.
The physical properties of the metal change during heat treatment, its structure changes completely or partially. As a result, the metal is easier to process, and its performance properties become better.

3. Design features. Technical description. Equipment advantages.
3.1. Design features.
The unit has a vertical design: the heating chamber is located on top, parts are loaded at floor level (zero level), the hardening tank is recessed into the floor.
A device with adjustable drives loads and unloads the product, providing smooth acceleration, braking, precise positioning, and a given speed of movement of the product.
Electrically driven fans ensure uniform temperature field.
Each of the nine heating zones has two thermocouples that provide temperature regulation and control.
Screen thermal insulation is installed on top of the heaters. It ensures maintenance of the specified temperature.
The design of the tank ensures heating of the quenching medium (water) in the temperature range of 20 - 95 ± 5ºС and mixing.
Repair platforms and ladders make servicing the furnace convenient.

3.2. Technical description of units and control systems and plant support.
The plant includes the following main components:
- heating chamber.
- loading and unloading mechanism.
- sliding hearth.
- load device.
- hardening tank.
- control system.

Heating chamber.
The heating chamber has a rectangular shape. Nichrome belt heaters of a zigzag design are installed inside the chamber on the sides and ends. At the top of the heating chamber, centrifugal fans are installed on a separate platform for air circulation. There is a gap between the heaters and the loaded product. The camera is installed on a base that rests on 4 columns. Heating transformers and cooling cabinets are installed on the base.

Loading and unloading mechanism.
The loading and unloading mechanism has a special device with a drive for lowering the basket from the working chamber into the quenching tank.

Sliding hearth.
A sliding hearth with a clamping mechanism is used to close and seal the working opening of the furnace. Electromechanical drives and rack and pinion transmission perform fix and pressing. The hearth moves along guides.

Loading device.
The loading device lifts and moves the cage.

Quenching tank.
Quenching takes place in a quenching tank. Heating modules heat the water for quenching. For better heat transfer, bubbling is used. The tank has a sliding lid with a drive.

Control system.
The control system integrates the entire flow of information:
- organization of the interface with the operator-technologist;
- software control of the heating process;
- identification of the state of the technological system;
- documentation of the technological process;
- dispatching of the given tasks.
The control system ensures operation of the plant in the following modes:
- manual control;
- programming;
- automated;
- semi-automatic.
The plant control panel consists of a personal industrial computer and a touch screen. The control panel digitally displays the main parameters of the heat treatment process:
voltage on heaters;
temperature in the furnace by heating zones;
operation of fans;
current in heaters.
The control system has the ability to record and store the technological process with output to a printing device:
current time;
temperature in each zone.
The control system has a light and sound alarm about deviations in the technological process:
broken thermocouples;
exceeding the set temperature;
heater malfunction.

3.3. Equipment advantages.
The main advantages of chamber furnaces for heat treatment of metals:
- versatility (heating of parts of different sizes and weights is allowed);
- simple design, eliminating problems with finding spare parts;
- high efficiency;
- economical energy consumption due to multi-layer thermal insulation;
- reliability and safety.