JLS have for many years been an industry leader and go to name, in the design and manufacture of AMS2750 & Nadcap compliant industrial ovens. With our many years of experience and wealth of knowledge, JLS are supplying an ever increasing number of ovens for our clients in the Aerospace and Defence industries, as well as for Contract Heat Treatment companies.



Oven / Furnace Class

Temperature Uniformity

     °C              °F

1 ± 3 ± 5
2 ± 6 ± 10
3 ± 8 ± 15
4 ± 10 ± 20
5 ± 14 ± 25
6 ± 24 ± 50

With more and more clients needing to comply with the requirements of AMS2750E, JLS are tasked with ever greater technical challenges. Nevertheless, we have not yet been met with a challenge that we could not accomplish! We continue to push the boundaries of what can be achieved in terms of reliability and performance of air circulating ovens. JLS can offer products designed and built to comply with AMS2750 Class 1 to 6, and instrumentation types A to E. If you are in any doubt as to your specific requirements, JLS are always on hand and happy to assist.

By working in close partnership with our clients, JLS can specify and design products to meet their specific needs - Please contact JLS with details of your specific requirements.

For further information and clarification of AMS2750 and Nadcap, please read below. You will also find some reference tables that are often very useful when defining and specifying your specific requirements:


AMS2750E / Nadcap Instrumentation Reference Table







Each control zone has a thermocouple connected to the controller X X X X X
Recording of the temperature measured by the control thermocouple X X X X
Sensor for recording the coldest and hottest spots X X
Each control zone has a charge/load thermocouple with recording system X X
Each control zone has an over temperature protection device X X X X

NADCAP / AMS2750 / CQI-9

Introduction (What are AMS 2750 & Nadcap?)

AMS 2750E is a pyrometry specification that focuses on continual improvement in the Aerospace industry by employing procedures, calibration data, timelines, record archiving, thermocouple guidelines and applications, System Accuracy Testing (SAT) and Temperature Uniformity Surveys (TUS). The current revision is ‘E’ which came in to effect in 2012.

Standards such as the AMS 2750 E are applicable for the industrial processing of high-quality materials. They define industry-specific requirements for heat treatment. Today, the AMS 2750 E standard and derivative such as AMS 2770 for the heat treatment of aluminium are the guidelines for the aerospace industry. These standards describe in detail the requirements applicable to thermal processing plants.

Nadcap provides a systematic approach of checkpoints to ensure the achievement of required control and reproducibility of a specific process for which approval is being sought. There are many heat treating processes for which Nadcap accreditation may be sought. Normally speaking, most heat treating companies will seek acceptances that relate specifically to their actual processes.

Fig. 1. Number of TUS sensors required for batch ovens, furnaces, salt baths, controlled temperature liquid baths, fluidized-bed furnaces or continuous/conveyorised ovens/furnaces using the volumetric method:
Workspace volume less than:





















Number of sensors(1)

Classes 1 and 2 (formerly class 1)

5 9 14 16 19 21 23 30 35 40

Number of sensors(1)

Classes 3 thru 6 (formerly class 2)

5 9 12 13 14 15 16 20 23 25
Ft3 per sensor, classes 1 and 2 < 1 25 21 25 32 38 43 67 86 100
Ft3 per sensor, classes 3,4,5 & 6 < 1 25 25 31 43 53 63 100 130 160
  1. For salt bath furnaces where a single probe is used for the TUS, the above numbers represent sensor locations.
  2. For oven/furnace volumes greater than 113m3 (4000ft3) use the appropriate class formula to calculate number of sensors:
  • Classes 1 & 2:        9 + (1/2 times [the square root of (oven/furnace volume in ft3 – 225ft3)]) or

                                 9 + [1/2 times (the square root of [35.3 times (oven/furnace volume in m3 – 6.4 m3)])]

  • Classes 3 thru 6:    9 + (1/4 times [the square root of (oven/furnace volume in ft3 – 225ft3)]) or

                                 9 + [1/4 times (the square root of [35.3 times (oven/furnace volume in m3 – 6.4 m3)])]

  1. For oven/furnace volumes less than 113m3 (4000ft3), it is acceptable to use the appropriate formula or interpolate using the data in Fig. 1.

Removing the Anxiety

The common fears and anxiety surrounding AMS & Nadcap compliance can be reduced simply. This is done by increasing knowledge and understanding, which only takes a relatively small amount of research in to a specific field, and proper implementation of the requirements, combined with adherence to required guidelines and checklists.

In general, you must first understand the differences between Aerospace Materials Specifications (AMS) 2750E and Nadcap certification from a topical view. While the two normally form a synergistic bond, they must first be separated in order to understand the fundamental differences between them. For aerospace material heat treatment, this understanding is critical, because most Nadcap inspectors require adherence to AMS 2750E before granting consideration of your specific aerospace-related processes.

At JLS we help remove the most common cause of auditing related headaches, by designing and building our ovens to consistently pass temperature uniformity surveys (TUS), and systems accuracy tests (SAT) by a comfortable margin. This will ensure you have less to worry about when it comes time for your audit…

Aerospace Prime Specifications

In addition to AMS 2750E and Nadcap, most Aerospace manufacturers have their own specifications that you must meet in order to run their parts. In many cases, the Aerospace prime specifications are stricter than that required for AMS 2750E and Nadcap certification. Best practice would be to make sure you are certified to the strictest specifications related to your customer's requirements and processes.


These are some of the other derivatives of AMS2750 that we are asked to comply with, when designing an oven or furnace for a specific application.

  • AMS2769 – Heat Treatment of Parts in a Vacuum
  • AMS2770 – Heat Treatment of Wrought Aluminium Alloy
  • AMS2771 – Heat Treatment of Alloy Castings
  • AMS3025 – Polyalkalene Glycol Heat Treat Quenchant


What is CQI-9? - Continuous Quality Improvement (CQI) was published by AIAG (Automotive Industry Action Group). CQI-9 is based on the above described AMS2750, it was published in response to a realisation that the automotive industry needed top up its game, so they looked to the aerospace industry for guidance.

CQI-9 defines the fundamental requirements for heat treat management systems, addresses the process approach to automotive production, mandates an annual self-assessment, and provides for continual improvement.

The CQI-9 Requirement is applicable to first tier commercial heat treaters and captive heat treaters to the OEM automotive industry as well as second tier heat treaters that provide service to first tier suppliers. Third tier heat treaters may be required to adhere to the CQI-9 requirements, but it is not mandatory unless requested.

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