SAE AMS 2750H-2024: Pyrometry

Accurate, non-contact temperature measurement is imperative in industries and industrial processes for melting, heating, drying, forming, or heat-treating materials. Pyrometers assure precise temperature control and thereby product quality and safety. SAE AMS 2750H-2024: Pyrometry establishes pyrometric requirements for equipment used for the thermal processing of metallic materials.

What Is Pyrometry?

Pyrometry is the measurement of high temperatures by analyzing the radiation emitted from a surface. It is a non-contact measuring technique for temperatures that is used in chemical engineering as well as in the automotive, glassmaking, metalworking, food processing, aerospace, and manufacturing industries, which require heat treatment at precise temperature control. In these industries, it is critical to know the exact temperature at multiple locations to maintain accurate properties of the material that is being produced.

What Are Pyrometers and How Do They Work?

“Pyrometer” originates from the Greek words meaning fire and measurement, which originally was used to describe an instrument that measured high temperatures, for both non-contact and contact instruments.

When measuring temperatures where physical contact is not possible, thermal sensors called pyrometers are used. They are essentially a special thermometer that uses invisible heat waves to measure heat. These optical devices work by detecting infrared (IR) radiation: a specific part of the electromagnetic spectrum that is not visible to the naked eye. All objects with a temperature (including cold objects) emit IR radiation; as an object’s temperature increases, so does the amount of IR radiation emitted.

A pyrometer works by using a lens to focus the IR radiation onto a detector that converts the IR radiation into an electrical signal. The temperature of the object can be calculated from the strength of the IR radiation detected.

What Is SAE AMS 2750H-2024?

SAE AMS 2750H-2024 covers pyrometric requirements for equipment used for the thermal processing of metallic materials. Specifically, it covers temperature sensors, instrumentation, thermal processing equipment, correction factors and instrument offsets, system accuracy tests, and temperature uniformity surveys. These are necessary to ensure that parts or raw materials are heat treated in accordance with the applicable specification(s).

When Should No-Contact Temperature Measurement Be Used?

Pyrometers should be used in situations where it is not possible nor practical to physically touch the object, such as in a hazardous environment. Non-contact temperature measurement is preferred or required under the following conditions:

• Moving objects: the target is moving or are out of reach (such as in the food service or medical applications)
• Hazardous environment: the target or the environment which encompasses the target is too aggressive, hazardous, or would otherwise adversely influence the output signal of a contact probe
• Contact would adversely impact the object: contact with the target would damage the surface or adversely impact the temperature measurement when in contact with the surface
• Object’s temperature is extremely high: The temperatures to be measured are too high for the respective thermocouple or other type of contact probe

SAE AMS 2750H-2024: Pyrometry is available on the ANSI Webstore.