Calibration Uniformity Procedure for AMS 2750

[Leite]

Hey guys, Someone have procedure explaining how to do a calibration and uniformity according to AMS2750, for relieve stress furnace (max 500 ?C)?

 

[Mikishots]

Re: AMS2750 rev D - para 3.2.6.2 - "Signature of the calibration company representati

Hey guys, Someone have procedure explaining how to do a calibration and uniformity according to AMS2750, for relieve stress furnace (max 500 ?C)?

Details. What's the material?

 

[Sorin]

Re: AMS2750 rev D - para 3.2.6.2 - "Signature of the calibration company representati

Hey guys, Someone have procedure explaining how to do a calibration and uniformity according to AMS2750, for relieve stress furnace (max 500 ?C)?

As Mikishots said, more details would be nice: range of the furnace, for what specifications the stress is done.

Would explain in Fahrenheit (cause it's easier to remember the numbers)

Say range is: 200C to 500C (392 F to 932 F)
Difference is less than 600F so you need to do any intermediate point at every survey and at least once a year the minimum and the maximum.
However if your parts are for Boeing and they are calling their own Pyrometry standard, the intervals between TUS points shall be no greater than 300 F in which case you should split your range in subranges no bigger than 300 F.
So, you would have one range from 392 to 600 (say) and one range from 600 to 932.
And now you shall cover each range at every TUS and at least once a year the maximum and the minimum.

That means you have 392-600-900. Assuming monthly TUS, in order to satisfy the requirements you shall perform TUS as follows:

January: 392 - 600 (you cover both ranges)
February: 600 - 932 (you cover both ranges)
After that you alternate every month. This way you cover both ranges every month and you also cover the minimum and maximum requirement.

 

[Leite]

Re: AMS2750 rev D - para 3.2.6.2 - "Signature of the calibration company representati

The material is Chrome silicon and chrome silicon + vanadium. Material used to valve spring.

We have many different furnace but in general work at the same temperature:
Range is: 392 F to 788 F


Actual procedure:
6. DESCRIPTION OF ACTIVITIES
6.1. Calibration of thermocouple + cables + pyrometers
6.1.1. goal
Check if all thermocouples, pyrometers and cables are correctly measuring the temperature of the oven.
6.1.2. frequency
Every 3 months the sets thermocouple cables + pyrometers are calibrated. Programming is done
through software CALI (Annex 1).
6.1.3. identification
Each set is identified with a sticker affixed to the front of the pyrometer. identification is a sequential number. In the case of a scraping of components (pyrometer, cable or thermocouple) their number is definitely discarded. Can not be reused when the set number of its components is substituted for another. The numbers of all sets are recorded in software CALI (Annex 1).
6.1.4. procedure
Without disconnecting the cable, the thermocouple is removed from the oven and placed in the oven along with the standard thermocouple default, both the qualified supplier. Calibration is performed at a temperature of 400 ? C and registered in the spreadsheet of results for subsequent typing the electronic certificate. The acceptance criteria is defined in IT-400.29.06 (is 0,008 x measured temperature for type J,K and 0,006 x measured temperature for types E,S,R and B. For PT-100 maximum error is 36.5 F).

6.1.5. Calibration of the temperature controller
The temperature controller is disconnected and the thermocouple attached to the portable calibrator (Cappo). The
Cappo simulates the temperature in the furnaces commonly used, calibration is performed in two different temperatures to 428 F and 626 F. Calibration is performed at a temperature of 752 F and registered in the spreadsheet of results for subsequent typing the electronic certificate.

 

[Sorin]

Re: AMS2750 rev D - para 3.2.6.2 - "Signature of the calibration company representati

@Leite

For your 6.1.5
You may have a problem because the instrumentation shall be calibrated as per manufacturer instruction or at three points: low, high and midpoint of the range.
In your case, with a range of 392 to 788, the calibration points shall be 392, 590 and 788.

For reference is AMS2750 rev D Para 3.2.5.3.1 which is a little ambiguous (but is the standard).
Also, you do not mention the sensitivity check which is also required for the calibration of instrumentation.
Sensitivity is a pass/fail test.

Sensitivity: The temperature change in the input that is required to activate a change, either upscale or downscale on the instrumentation. It is normally one-half the numerical value of the dead band, such as: a sensitivity of 1 ?F (0.6 ?C) is equivalent to a dead band of 2 ?F (1.1 ?C).

That means that you have to simulate a change of 1 F (for instrumentation on class 1 and 2 furnaces) and this change shall translate as a change of 1 F on your instrumentation.

It is usually done at a point in the middle range of your instrumentation.

 

[BradM]

Leite, I have created a new thread for your question . Let me or another moderator know if something should be changed.