Readers send us quite a number of questions related to planning and preparing for Nadcap audits and for suggestions about the offsets during SAT and TUS. Here is a sampling.

Question #1:
How can I obtain Nadcap for just one operation – processing of Beryllium-Copper in salt?

Answer #1:
You will need to go through the Nadcap process, but the scope of the audit would only include the functions and customers for which you are pursuing accreditation. Nadcap will not audit other processes if it is not in the scope.

The following Nadcap documents should give you a good head start toward compliance. It is important you also meet AS9100 (Standardized Quality Management Systems for the Aerospace Industry) or have a similar quality management system in place. Also, compliance with AMS 2750D (Pyrometry) is mandatory. The documents you may wish to review include:
  • Preparatory Instructions for Nadcap Audit Applicants
  • Heat Treating Task Group Audit Handbook
  • AC7102 Rev D: Audit Criteria for Heat Treating
  • AC7102/S: Supplementary Audit Criteria for Heat Treating
  • AC7101/4 Rev C: Audit Criteria - Materials Testing Laboratories (Metallography & Microhardness) - if metallography is used in support of in-house heat treating
  • AC7101/5 Rev B" Audit Criteria - Materials Testing Laboratories (Hardness) - if hardness testing is used in support of in-house heat treating
  • Heat Treating - Preliminary Questionaire
  • Heat Treating Task Group - Pyrometry Guide
  • AS9100 Certification and Registration Process
Several valuable websites include:

1. www.pri-network.org
2. www.sae.org/technical/standards/aerospace/TEST
2. www.sae.org/technical/standards/AS9100B

In addition, you will need to complete all applicable sections of AC7102 (this could include hardness testing and metallography - 7101/5 and 7101/4, respectively depending on what testing you perform). Not all sections of AC7102 will be applicable and can be identified as such during an internal audit. Finally, you will need to make sure the any furnaces not covered in the scope are not used as part of the BeCu processing.

Question #2:
Let’s assume we are using internal intentional offsets of 4°F (electronically applied to the controller, not manual). Since the furnace controller will take the offsets and the correction factors of furnace thermocouples into account, we should not apply these offsets and correction factors algebraically to temperature indication of the controller during evaluation of SAT because they’re already reflected to the furnace display. Is that correct?

Answer #2:
For this to be a valid approach, the same correction factors would need to be applicable for all temperatures (unlikely to happen) or the furnace runs at only one temperature. Otherwise this is why AMS 2750D does not complicate the process control thermocouple correction factor (if furnace runs multiple temperatures/ranges). In this case, the offset should only be applied for the thermocouple correction factor (I'm not sure what's meant by "the furnace controller will take the offsets and the correction factors of furnace thermocouples into account)." To use this method you would need to have a written procedure on how you are using internal correction factors and how they are controlled. I do not believe AMS 2750D provides adequate detail to cover this subject. I recommend you contact PRI.