1. Purpose of the equipment. Technological processes used in the equipment.
The recirculating thermal heating unit “ARTN-13.5” 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 because 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 via radiation and convection. Therefore, high temperature uniformity is done in the working space of the furnace.

After the hardening product becomes more hard and wear resistant. The metal is heated, held for some time, and then cooled quickly.
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.
Artificial aging - the hardened product is heated and maintained at an elevated temperature and then cooled in air.

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 determines directly 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 being easier to process, and its performance properties become better.

3. Design features. Technical description. Equipment advantages.
3.1. Design features.
Thermal insulation is made of modern materials and serves to maintain a given temperature regime.
The unit has a device for loading and unloading the product from the workspace.
The unit has nine adjustable zones with heating sections installed. Each zone has controlled radiation and aerodynamic heating systems.
The unit's current terminals are provided with reliable protection against heating.
The surface temperature of the unit body does not exceed 60°C.
The unit has a screen between the heating elements and the product loaded into the unit.
A sliding hearth with a hearth clamping mechanism serves to close and seal the working opening of the furnace of the unit.
There is a device for loading and unloading the basket from the unit chamber.
The mechanism for moving the cage from the position of loading products to the initial position for loading is installed at the zero mark of the unit.
Resistive heaters in the heating sections are made of modern materials with a long service life.
Each of the nine heating zones has two thermocouples that provide temperature regulation and control.
Each zone has one centrifugal fan for uniform temperature distribution in the working space of the unit.
Screen thermal insulation is installed on top of the heaters. It ensures maintenance of the specified temperature.
The safety system prevents overheating of products during heat treatment. It consists of a processor that evaluates the hottest working thermocouple, the temperature of which exceeds the upper temperature tolerance and disconnects the unit from the supply voltage.
The unit has a device for recording the actuation time of the actuators.
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.
The design of the tank ensures heating of the quenching medium (water) in the temperature range of 20 - 95 ± 5ºС and mixing.
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.
- boot 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. Centrifugal fans are installed on a separate platform for air circulation at the top of the heating chamber . There is a gap between the heaters and the loaded product. The camber is installed on a base that rests on 4 columns. Heating transformers and cooling cabinets are installed on this 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 fixing 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.