Temperature measurement in the steel industry: precise control from melting to rolling

Temperature has a decisive impact on steel quality and overall process stability. Non-contact infrared temperature measurement enables hot and moving materials to be monitored throughout production, from melting and continuous casting to reheating, rolling and controlled cooling.

Temperature deviations affect steel properties

Steel production consists of a series of temperature-critical processes. Temperature must be controlled precisely to ensure that the material can be cast, formed and processed further under the right conditions.

If the temperature is too high or too low, it can affect process speed, energy consumption and the quality of the finished product. Deviations can lead to inconsistent material properties, problems during rolling or unnecessary production waste, among other issues.

Continuous temperature measurement allows operators to detect deviations and adjust the process before they affect larger quantities of material.

Non-contact measurement of hot and moving steel

The high temperatures and movement of the materials make it difficult to use traditional contact sensors throughout steel production. Infrared pyrometers and thermal cameras measure temperature from a distance without coming into physical contact with the workpiece.

This makes the technology well suited to applications such as molten metal, hot slabs, billets and steel products moving rapidly through a rolling mill.

The choice of measuring equipment depends on factors including the temperature range, measuring distance, workpiece size and surface, as well as conditions such as dust, steam and scale. The emissivity of steel can vary with its surface condition, so this must be taken into account when selecting and configuring the measurement solution.

Critical measurement points throughout production

Measurement points should be positioned where temperature data can be actively used to control the process, document quality or protect production equipment.

  • Melting: Monitor the temperature of the molten steel to support a stable process and correct subsequent treatment.
  • Continuous casting: Check the temperature as the steel solidifies and is formed into slabs, blooms or billets.
  • Reheating furnaces: Ensure that the material reaches a uniform temperature before it moves on to rolling.
  • Furnace exit: Record the temperature immediately before processing so that the process speed can be adjusted.
  • Hot rolling: Track the temperature between individual rolling stands and throughout the rolling process.
  • Controlled cooling: Monitor the cooling process, as the cooling rate affects the final properties of the steel.
  • Coils, plates and sections: Check the temperature of the finished or semi-finished product before further handling.
  • Furnaces and refractory material: Use thermal monitoring to identify areas with abnormal heat loads or early signs of damage.
  • Quality control: Store temperature data as evidence that production has met the specified process requirements.

The measuring equipment can be integrated with the plant’s control system so that temperature data is used for alarms, documentation and automatic process control to optimise pressing speed and produce consistent products with less waste.

Better process control and more consistent steel quality

Continuous temperature data provides a more precise basis for controlling furnaces, casting, rolling and cooling. When operators can respond quickly to temperature deviations, the risk of defects and rejected workpieces is reduced.

Better temperature control can also limit unnecessary heating and support more efficient energy use. Thermal monitoring of furnaces and production equipment can also provide early indications of overheating, wear or damage, thereby supporting preventive maintenance.

Hans Buch offers solutions from AMETEK Land for infrared temperature measurement in the steel industry. The solution is tailored to the specific process stages, materials, temperatures and conditions in the production facility.

Temperature measurement

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Rasmus Riis Mortensen

Sales Manager, External Sales

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Market Manager