A System Accuracy Test (SAT) checks whether a furnace’s control or recording system measures correctly as a whole. The thermocouple, lead wire and instrument may each be calibrated, yet together they can still drift. The SAT catches that total error. It is required under AMS2750 alongside the TUS.
The mistakes behind failed or questioned SATs
- Test sensor not placed close enough to the furnace sensor
- Correction factors applied with the wrong sign
- No new SAT after a furnace sensor change
- Earlier loads not reviewed after an out-of-limit result
- Missed test intervals
Which of these is in your records?
Knowing the list is easy. The real question is which one sits in your own records. They slip past when files are read by eye, and auditors look for them first. Upload your SAT readings to NTB SpecPro and see in minutes which points carry risk, why, and what to do next.
The NTB SpecPro heat treat module applies corrections, calculates the difference, compares it with the limit and prepares the report. Final evaluation stays with your authorized pyrometry personnel.
General information only; does not replace the standard. Use the current AMS2750 revision for distances, intervals and limits.