Weld Repair Preheat Temperature

[Berryit]

Good afternoon,
Being new to the job, I reviewed a Quality Control Procedure which mentioned the need for preheating the area of the weld repair 150 degrees F. higher than the normal welding procedure preheat temperature. We have looked in ASME Section IX, Section VIII, Section V, API-8C and AWS D1.1 and have found nothing directing a specific preheat range or higher preheat temp for a weld repair. Could anyone provide the needed procedure / specification???

 

[metengr]

Preheat would be defined by the original code of construction or in-service repair codes like API 570 or the National Board Inspection Code. These would be minimum preheat temperature based on the base material to be welded. High preheat can be mandated without WPS re-qualification.

 

[Berryit]

Thank you for taking time to respond to my inquiry.
I was merely hoping someone might remember which document / which specification / which procedure may / might have an instruction to preheat the area of a weld repair 150 degrees F higher than the preheat requirement as shown on the related WPS / PQR whether it be ASME, AWS, API or . . . .
Again, thank you.

 

[metengr]

The preheat requirement on a WPS is the minimum qualified to allow flexibility and may not be the preheat requirement required by the code of construction. Thus, you can have a wide discrepancy.

 

[Berryit]

I agree, but still want to see where something tells the requirement of having
the preheat temperature for a weld repair increased by 150 degrees F.
What about 125 degrees? What about 200 degrees? I know there is also a
metallurgical concern such as hydrogen cracking, HAZ hardness, weld metal
cooling rate etc. Still for someone to arbitrarily state all weld repairs
shall be preheated 150 degrees F higher than the normal for the related
WPS is . . . . ????
Thank you sir.

 

[metengr]

I don't believe there is such a document.

 

[weldstan]

I know of no such Code or Standard.
There are some repairs, depending on geometry or actual material's C.E. where preheating should be increased over that normally required under a Specific Code or Standard.

 

[DeleteriousPhases]

how long ago was the quality manual created? does it mention specific P numbers or just any time a repair is needed?

 

[Berryit]

Hi and thank you all for your interest in providing a solution to our "dilemma."
The preheat statement was found in a gneric procedure for making any type of
weld repair at my employer. To date there has been alot of research and we have
found no docment providing a path for us to justify the direction of the document.
We removed the statement from the document and used the preheat information from
AWS D1.1 and ASME Section IX about using the preheat as provided by the related
weld procedure specification (WPS) and 'called it a day.'

 

[weldstan]

Preheat minimums are defined in Codes like B31.1, B31.3, D1.1, etc. - not IX.