Process Control

What are Endothermic Processes and Heat Treatments?

Endothermic process and heat treatments are essential for ensuring high-quality metal and alloy products. Heat treatments are commonly used to alter the physical or chemical properties of materials such as metals and alloys, including steel. Heat treatments result in changes in material microstructures that provide increased hardness, temperature resistance, ductility, and strength.

Carburising is a heat treatment process in which iron or steel absorbs carbon while the metal is heated in the presence of a carbon-bearing material, such as charcoal or carbon monoxide. The intent is to make the metal harder. Depending on the amount of time and temperature, the affected area can vary in carbon content. Longer carburising times and higher temperatures typically increase the depth of carbon diffusion.

Endothermic gas is required for the hardening or carburising of steel and is a mixture of carbon monoxide, carbon dioxide, methane and other gases. It is often used as a ‘neutral’ protective gas or carrier gas during heat treatment process. Monitoring and controlling the furnace gas composition is essential to ensure metallic products retain their desired properties.

How are Gas Sensors used within Process Control?

Carbon dioxide and carbon monoxide levels must be carefully controlled in heat gas treatments. Gases are often introduced to furnaces during heat treatments to provide a protective environment, controlled oxidation, or to act as a carrier for substances intended to modify the material or surface.

For the desired metal treatment to be successful, the gas composition must be carefully monitored and strictly controlled. Measuring the concentrations of CO, CO₂, H₂, H₂O, N₂ and CH₄ in the generated endothermic gas atmosphere can help ensure that both the endogas generator and the furnace are operating correctly and prevent any undesired reactions.

By carefully controlling the amounts of each gas and the temperature in the treatment furnace, the steel surface can be hardened to provide long lasting components such as gears and tools.

• To find out more about gas sensing during heat treatments, take a look at this article from Edinburgh Sensors.

Which Edinburgh Sensors products are suitable for Process Control?

Edinburgh Sensors are a leading supplier of high-quality gas sensing solutions, including a comprehensive range of infrared sensors for reliable CO and CO₂ measurement. Please view our range below, and get in touch if you wish to discuss anything with a member of our team.