You must have heard about the thermocouples installed on heat treatment furnaces are required to be relaced periodically as per their temperature exposure in Deg C instead of recalibrating it..Do you know why is it so?
There are different types of thermocouples being used in heat treatment furnaces like Sealed Quench Furnaces ( SQF) , Continuous atmosphere furnaces, Annealing, Normalising furnaces etc.
The typical types of thermocouples widely used are Base metal thermocouples ( K,N,J,E,T) types for furnaces and processes operated upto 980 deg C . Noble metal thermocouples ( B,R,S,RTD) types normally used for higher temperatures like in vaccum furnaces etc.
Base metal thermocouples are required to be replaced every year Max.
If the operating temperature is equal to or less than 760 Deg C..and the same type of thermocouples used for tempering, stress relieving, quench oil controlling, are to be relaced every two years Max.
This is irrespective of their accuracy is well within the acceptable limits at the end of the one year or two years as the case may be.. It is not permitted or allowed to re-calibrate again as per AIAG CQI-9 guideline latest edition.
But this is not the same when you use Noble metal thermocouples on your furnaces, Noble metal thermocouples are allowed to be recalibrated or replaced every two years as per the frequency mentioned in AIAG CQI-9 guideline.
Then why there is a difference between base metal types thermocouples and Noble metal type thermocouples for recalibration not allowed in one type and allowed for Noble metal type ?
There are so many process related detailed requirements are mentioned in CQI-9 standard/ guideline, and these are to be followed and adhered to on regular basis.
All these things are explained in two days CQI-9 training program.
Please do fill up the inquiry form available on this website to register your requirement for training or audit including no of participants from your organisation or as a individual.
Regards
Trainer
Mangesh Rajhansa
SAIRAJ Consultant