Section IX PQR / WPS question 1

[solinar]

If a test specimen for a PQR is welded (SMAW) without preheat, and passes its required tests, may a WPS be written based on that PQR that does require preheat(an essential variable)?

Chapter and verse from Section IX would be appreciated.

 

[weldstan]

A decrease of preheat is the normal essential variable - not an increase.

 

[solinar]

I find Section IX so confusing!

Help me out here. Does an essential variable (say decrease of preheat > 100) refer to WPS preheat range being not more than 100 degrees less than the PQR, or the PQR actual preheat used being not more than 100 degrees less than the WPS range, or a production weld's [reheat not being more than 100 degrees less than the range on the WPS?

I think this might be where the disconnect is occurring.

Thanks!

 

[DekDee]

solinar,
If your PQR listed a preheat of 300 degrees then your minimum preheat on your WPS would be 200 degrees.
Therefore the minimum preheat on your production joint is also 200 degrees,
Regards,
DD

 

[aburafdi]

Solinar,
How to read the essential variable?
Essential variable is applied to WPS compared to PQR, not the other way around.

So in your case: you may apply preheat for your WPS.
However, when you put preheat on your WPS then the welder shall follow it. If you need to weld with preheat less than this WPS, you can revise your WPS or create a new WPS (still valid based on your PQR).

Regards,
AR