Applications
Heat treatment with vacuum furnaces is an advanced process used to modify the properties of metals, ensuring high precision and quality. These furnaces operate in oxygen-free environments, avoiding contamination and oxidation in the finished product. The heart of the process is the accurate control of temperature, which can be very high, often above 1500 °C, maintained with minimum tolerances.
Besoins:
Temperature control in the thermal process
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Digital recording of process variables
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Furnace high temperature limit switch
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Electrical heating loads control
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Temperature measurement in the thermal process
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Besoin:
Temperature control in the thermal process
Temperature is the most critical variable in the metal heat treatment process. Precise and repeatable control is essential to ensure consistent, high-quality production. This is particularly important in the aerospace and aeronautical sectors, where accuracy must comply with regulations such as AMS2750 and CQI-9. In vacuum furnaces, the control system must generate a detailed thermal profile, with several heating and cooling phases, each with specific parameters. An accurate temperature control allows to comply with the metallurgical specifications and ensure the conformity of the final product.
Solution:
The 1850 controller is the ideal solution for the precise and reliable control of furnace temperature. With its highly efficient control algorithm, the controller ensures compliance with the thermal specifications required by the treated materials.
Certified to be compliant with AMS2750 (aerospace industry) and CQI-9 (automotive industry), the 1850 controller is suitable for applications of these kinds, which require a high level of precision in thermal control.
Key features:
- Generation of set-point profiles;
- Control outputs for SSRs and motorised valves;
- Colour LCD interface;
- Multilingual diagnostic messages;
- Logic and mathematical operations.
Besoin:
Digital recording of process variables
The recording of temperatures during heat treatments is essential to ensure the quality and safety of the treated materials. Accurate monitoring and documenting the thermal parameters ensure that the treatment cycle meets the required specifications, preventing defects and variations in the final product. Furthermore, these records are a fundamental requirement to comply with regulations and industry standards, such as AMS2750 and CQI-9, which are particularly strict in the aerospace and automotive sectors. This process also ensures the traceability of every production batch, guaranteeing the total reliability of the production process.
Solution:
For data recording, Gefran offers the 3850T multifunction controller, a device that integrates several functions, including efficient data logging compliant with the ASM2750 and CQI-9 specifications. This function, associated with the Real Time Clock, can store process data, digital Input/Output signals and alarm conditions.
Key features:
- Graphical touch screen interface;
- Storage in open or encrypted format;
- Export of files locally or via Ethernet network;
- Export of data in .CSV or .PDF format.
Besoin:
Furnace high temperature limit switch
To protect the system and ensure the safety of operators in the event of furnace overheating, it is necessary to adopt suitable safety devices, known as safety limit switch. Excess heat can compromise the integrity of the furnace, damaging resistors, sensors and refractory insulation, with the risk of fire, explosion or mechanical failure. In the event of malfunction of the primary system and exceeding the threshold, the safety system automatically operating by activating alarms and shutting down the plant, preventing damage and protecting operators. In the US market, the Factory Mutual (FM) regulation requires devices to be certified, to guarantee correct operation if the allowed temperature is exceeded.
Solution:
The 650L (48×48 format) and 1250L (48×96) safety indicators, with Factory Mutual (FM) certification, are devices designed to detect overtemperatures in industrial heating processes and activate a signal that move the system in safety mode. For easier installation and use, they are supplied with a ready-to-use configuration, inclusive of the function of retentive alarm memory, with operator acknowledgement action required. Acknowledgement procedures can be done by pressing a dedicated front key (red R), digital input (optional) or serial line (optional). The LCD display screen shows clear messages that guide the operator in identifying the system’s status, making interventions simple and immediate.
Besoin:
Electrical heating loads control
In vacuum furnaces, the heat treatment of metals requires very high temperatures, above 1500 °C. Special materials, such as molybdenum, tungsten or graphite, are used to build the heating elements because they are resistant to such extreme conditions.
Power control in industrial electric heating is fundamental to ensure temperature uniformity, efficiency and operational continuity. Systems must adapt to different loads – from linear resistors to transformers – maintaining stability even when the process varies. Flexible solutions are needed, with advanced diagnostics, compatibility with modern protocols and effective I/O integration. Compact and robust systems ensure safety, efficiency and reduction of system downtime.
In electrical heating, Power Controllers are used to ensure treatment temperatures above 1000°C, as these smart devices manage electrical heaters power precisely and efficiently.
The key features of the GPC series are:
- Current ratings from 40 to 600 A;
- Single, two- and three-phase configurations;
- Configurable control modes;
- Integrated diagnostics;
- Fieldbus connectivity.
Besoin:
Temperature measurement in the thermal process
Temperature is the most critical variable in heat treatment processes. Accurate control is crucial to guarantee the required mechanical properties, process repeatability, compliance with quality standards and operational safety. The temperature probe must operate in high temperature environments, ensuring a stable and continuous measurement. The sheath that protects the sensitive element, usually a thermocouple, is crucial. In applications with vacuum furnaces, this sheath must withstand high temperatures and must be made with low degassing materials (to avoid contamination in the vacuum environment), ensuring an accurate and stable measurement over time.
The TC9 series temperature probes, equipped with a thermocouple sensitive element, are an ideal solution for heat treatment applications with temperatures that rise up to 1600°C. The possibility of choosing the type of thermocouple, the measuring range, the installation length and the material of the sheath are why these devices have such high versatility of use.
Operating principle
Vacuum furnaces are the ideal solution when very high precision heat treatments in a controlled and contamination-free environment are required. By removing air and oxygen from the treatment chamber, these systems eliminate the risk of oxidation and ensure maximum purity of materials, minimising post-treatment processing.
By uniformly distributing heat, vacuum furnaces ensure homogeneous and repeatable results, which are essential for applications in the aerospace, medical, automotive and metallurgy sectors. The integration of advanced technologies for the control of temperature and pressure allows operators to manage each step of the process with extreme precision.
Electric heating, combined with smart control systems, offers high energy efficiency, optimising consumption and performance – a strategic choice if the focus is quality, reliability and sustainability.
Requirements and Technology
In vacuum furnaces, accurate temperature control is a strategic element to ensure reliable, repeatable and very high quality processes. To meet the needs of the most demanding sectors – such as aerospace, medical and automotive – advanced digital systems are used, including PID controllers, which can manage each phase of the thermal cycle with extreme accuracy.
The absence of air means that vacuum furnaces require special electrical resistors, such as graphite or molybdenum silicon (SiC) units, which can operate at extreme temperatures. In this context, the control of electrical power becomes crucial.
This is where Power Controllers come in. These smart devices are designed to optimise energy dynamically and responsively, improving performance, safety and energy efficiency. This technology not only guarantees excellent results, but also a sustainable and intelligent management of the thermal process.
