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Smart heat treatment solutions in the aerospace industry

Download AMS2750G Pyrometry Solution Note

AMS2750G pyrometry solutions

Heat treatment is a Nadcap℠ ‘special process’. Any process that can change or alter a part’s material or physical integrity by introducing stresses via mechanical, thermal, or chemical operations may be considered a special process and must be given particular care to avoid potential defects. AMS2750 was created to provide standardized pyrometry requirements (temperature measurement) in the heat treatment of products for the aerospace industry. Organizations need qualified employees and a well-documented set of procedures and approved equipment to provide evidence that proves both the procedure and results of each batch processed. Nadcap acts as the approval body for ‘special processes’ for aerospace manufacturing and is administered by the Performance Review Institute (PRI). Regular audits are undertaken to ensure facilities meet the requirements. AMS2750 is also referenced in other special process standards and has been adopted in different forms for the automotive (CQI9), oil & gas, and other industries.

Find out how our AMS2750G pyrometry solutions can help you: 

AMS2750G overview

The AMS2750 specification covers pyrometry requirements for equipment used in the thermal processing of metallic materials. The following provides an overview of the main sections addressed by Eurotherm products. Please refer to the AMS2750G standards for the full detail (www.sae.org).


Thermocouple accuracies
R, S
±1.0°F or ±0.6°C or ±0.1%
J, K, N
±2.0°F or ±1.1°C or ±0.4%

Figure 1

Usage period
Set temp. (°F)
Set temp. (°C)
One use
Quarterly or 10 uses
>2200 to ≤2300
>1205 to ≤1260
Quarterly or 90 uses
>1800 to ≤2200
>980 to ≤1205
Quarterly or 180 uses
>1200 to ≤1800
>650 to ≤980
Quarterly or 270 uses
>500 to ≤1200
>260 to ≤650
Quarterly or unlimited uses

Figure 2

Temperature sensors (section 3.1)

This section in the standard outlines the sensor job, use, type, calibration and accuracy requirements. Figure 1 gives an example of common thermocouple types and accuracy requirements.

Thermocouple construction includes both expendable (any portion of the thermal element exposed to the process environment) and non-expendable thermocouples (thermal element protected from the process environment e.g., metal sheath).

Base-metal non-expendable load thermocouple usage is dependent on temperature. Control thermocouple replacement period should be based on data from SAT, TUS, re-calibration, trend analysis and results.

Control thermocouple replacement period should be based on data from SAT, TUS, re-calibration, trend analysis and results.

Instrument accuracies
Field test
±1.0°F or ±0.6°C or ±0.1%. Shall be digital and have a readability of 0.1°F or 0.1°C.
Control, recording instruments
±2.0°F or ±1.1°C or ±0.2%. Recording instruments shall be digital and have a readability of 0.1°F or 0.1°C

Figure 3

Instrumentation (section 3.2)

This section outlines the instrument job, type, calibration and accuracy requirements.

Figures 3 and 4 outline the key instrument type requirements supplied by Eurotherm.

Data recording instruments should be checked annually to the accuracy of ±1 min/h by an external timing device (timing device calibrated every 2 years to ±1 s/min).

A possible alternative is to document digital synchronization to NIST (or equivalent) via satellite, internet, or phone (at least monthly) to support these accuracy requirements.



Calibration intervals
Field test
Control, recording instruments
Class 1 monthly
Control, recording instruments
Class 2,3,4 quarterly
Control, recording instruments
Class 5,6 semiannually
Control, recording instruments
Refrigeration and quench equipment calibration semiannually

Figure 4

Thermal processing equipment (section 3.3)

This section defines the furnace class (1-6) uniformity tolerance and the instrumentation type (A-E).

SAT (section 3.4) describes a probe check to assess the variation from the process control systems with an independent master thermocouple and field instrument.

TUS (section 3.5) is used to assess the temperature variation within a qualified work zone with respect to setpoint temperature.




Furnace class

Figure 5

Sensors per control zone
Type A
Type B
Type C
Type D+
Type D
Type E
Hot & Cold
Additional Record

Figure 6

Heat treatment solutions to help meet AMS2750G

When subject to the necessary field calibration, the following instruments manufactured by Eurotherm are suitable for use in the aerospace industry (Nadcap/AMS2750) and automotive (IATF16949/CQI9 version 4).

Process control or recording (AMS2750G Table 7)

Calibration to meet ±2.0°F or ±1.1°C or ±0.2% of temperature, whichever is greater.

Eurotherm instrument
Model numbers
All models
EPC3016, EPC3008, and EPC3004
With enhanced thermocouple board (ET8)
EPC3000 series FM option can meet the integrated control/over-temperature requirement
Control and recording
All models
Control and recording
Control and recording

Figure 7

Field test instruments

6000 series graphical recorder, model numbers: 6100A TUS and 6180A TUS with external CJC and fast-acting accuracy to meet ±1.0°F or ±0.6°C or ±0.1% of temperature, whichever is greater.

¹Devices for use in data acquisition (AMS2750G 3.2.4). Please refer to table below for electronic record solutions. Simple Network Time Protocol (SNTP) is available in the 6000 series graphical recorder, nanodac recorder/controller, E+PLC range, PAC system hardware (model numbers T2550, T2750), and Eycon 10/20 visual supervisors to provide digital synchronization to help meet recording timing accuracy.

Electronic records
AMS2750G clause
CQI-9 4th Ed.
Eurotherm solutions
Tamper evident
Records unalterable without detection. Eurotherm 6000 series recorders, nanodac recorder/ controller, versadac scalable recorder, E+PLC controller, and T2750 PAC controller create writeonce, read-only data records in a tamper-evident binary file format with the file extension .UHH.
Record playback
Source data unalterable in reviewing tool. Eurotherm Data Reviewer software utility enables playback of the data in an easy to examine trend format. The source data is recorded in a tamper-evident file format.
Records in readable form
Section 4 job audit
Accurate, complete records for inspection, review, and copying. Eurotherm Data Reviewer and Ocean Data Systems Dream Report software can generate accurate copies of records in humanreadable and electronic form, suitable for inspection, review, and duplication.
Record review
Section 4 job audit
Evidence of record reviews in electronic or printed format. Eurotherm Data Reviewer has an embedded annotation function to provide evidence that the record was reviewed - this review then becomes a part of the permanent record. The record can be printed as a PDF file (for electronic review) or a hard-copy for physical marking to verify review.
Protection of records
IATF 16949:2016 defines retention periods
Retrieval of accurate records throughout the retention period. Eurotherm Data Reviewer is a 2nd generation software utility that also accepts Eurotherm .UHH file formats created 15+yrs ago. Redundant archiving of the source data provides additional retention assurance. 6000 series recorders support secure FTP when transferring files to Eurotherm Data Reviewer. Eurotherm ‘store and forward’ feature automatically backfills data to servers if communications are temporarily lost.
Hardware and software operation
Operate throughout retention period (min. 5 years). The Eurotherm established obsolescence program ensures both hardware and software are supported throughout stated retention periods.
System access
Authorization methods of record access. Data acquisition products have an optional user management feature that can be used to manage password access.
Software revisions
Eurotherm Data Reviewer software revisions do not impact process parameters. Setpoint cycle revisions in PLC’s or programmers can be controlled by authorized access and quality procedures. Eurotherm control products have passcode protection on configuration. Eurotherm Data Reviewer operates independently to cycle setpoint programmers and will not impact process parameters on revision updates.

Figure 8

Industry 4.0 ready technology

Eurotherm control and data recording solutions are IoT ready, providing a data integrity layer within open IoT platform system architectures. Engineered solutions offered by Eurotherm include SCADA, MES, and IIoT system platform technologies for enhanced information visibility, data access and operations management. Our products, systems and services are designed with cybersecury-in-mind, aiding the digital transformation to Industry 4.0 technology.

Ecostruxure diagram

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