High-Temperature Sensors up to 600 °C: Force and Temperature Measurement under Extreme Thermal Conditions

Many industrial processes generate immense temperatures that would destroy conventional measurement technology within minutes. When metals discolour and standard adhesives burn, specialized knowledge is required. Octogon delivers custom-made load pins, load cells, and strain gauges that operate precisely and reliably even under extreme thermal loads of up to 600 °C.

Whether in heavy industry, near melting furnaces, or in material testing – we design sensors that withstand the heat without compromising measurement accuracy, while simultaneously providing valuable thermal process data.

The Technological Challenge in Force Measurement

Classic strain gauges (SGs) bonded with epoxy resins reach their physical limits at approximately 150 °C to 200 °C: the adhesive softens, the measurement grid detaches, and standard solder melts.

To produce load pins for a temperature range up to 600 °C, Octogon deviates from conventional sensor manufacturing methods and relies on highly specialized materials and application processes:

1. Ceramic Application of Measurement Grids

Instead of polymer-based adhesives, for high-temperature applications, we use special high-temperature-resistant strain gauges that are applied to the deformation body with ceramic cements and fired at defined temperature profiles. This ceramic layer provides electrical insulation and transfers the strain of the steel to the measurement grid without creep, even at 600 °C.

2. Connection Technology: Micro-welding of Connection Wires

Standard soldered connections are obsolete at these temperatures. To ensure absolutely heat-resistant signal transmission, Octogon's connection wires and internal contacts are not soldered, but directly joined using high-precision micro-welding processes. This guarantees a permanently stable electrical connection without thermal weak points at the transitions.

3. High-Temperature-Resistant Deformation Bodies

Steel changes its mechanical properties under the influence of temperature. It expands (thermal expansion) and becomes mechanically "softer" (the modulus of elasticity decreases). For sensors up to 600 °C, we process special heat-resistant stainless steels and high-temperature alloys (such as Inconel), which exhibit a linear elastic limit without plastic creep even at red heat.

Integrated Temperature Measurement: Two Measured Variables in One Component

In thermally demanding processes, temperature is often just as critical to the process as the force applied. Therefore, Octogon optionally equips its high-temperature load pins with fully integrated temperature sensors.

Through special axial bores in the core of the pin, we integrate high-precision temperature sensors (e.g., Type K / Type N thermocouples or high-temperature-resistant Pt resistance thermometers) that accurately measure the temperature at the point of force application.

Your Advantages of Dual Sensor Technology:

Active, Dynamic Compensation: While our sensors are already excellent temperature-compensated on the hardware side (TK-zero and TK-characteristic value), the exact, simultaneous temperature signal from the PLC or evaluation electronics enables additional computational compensation of residual errors in real time. The result is maximum precision over the entire temperature profile.
Process and System Monitoring: Temperature measurement directly in the clevis pin provides valuable data for predictive maintenance. For example, overheating in bearings or unexpected temperature peaks in melting furnace tilting devices can be detected early.
Space Saving: No separate installation space for external temperature sensors needs to be planned in the plant design.

Signal Output and Remote Electronics

A load pin may withstand 600 °C, but semiconductors and signal amplifiers cannot. In high-temperature applications, the electronics must be relocated out of the heat zone.

Special Cabling: For the parallel output of the passive $\text{mV/V}$ -force signal and the temperature signal, we use mineral-insulated cables (MI cables) with stainless steel sheathing or high-temperature-resistant fiberglass insulation.
Inline Amplifiers & Signal Converters: The signals are routed out of the hot area and processed by our compact DIN rail modules only in a thermally uncritical zone. This way, the force and temperature are simultaneously available to your control system as an industrial standard signal (e.g., $4 \dots 20\text{ mA}$ , PROFINET, IO-Link).

Typical Applications

Octogon's combined force-temperature sensors are designed for the harshest industrial environments. They provide data where standard components would melt:

Steel Industry and Metallurgy: Rolling force measurement in hot rolling mills, force and temperature monitoring on continuous casting plants, ladle turrets, and melting furnaces.
Plastics and Extrusion Technology: Cavity pressure and clamping force measurement at high processing temperatures.
Aerospace: Structural tests on engine components or in wind tunnels at extreme exhaust gas temperatures.
Energy and Power Plant Technology: Monitoring pipeline loads and thermal expansion in steam turbine networks.

Shed light on the black box of your high-temperature processes.

Are you facing the challenge of safely and precisely measuring forces and temperatures under extreme thermal conditions? Contact Octogon's engineering team for an application-specific design of your sensor technology.