Range qualified for heat input 2

[AndyVictor]

We find almost detailed (although, sometimes confusing) explanation on the range of base metal thickness, weld thickness etc qualified for a specific PQR. Is there any reference in Sec IX or else where, as to the exact range of values qualified with respect to Heat input and electric characteristics( current voltage etc) for procedure qualification - for example: +/- 10% ??.

 

[Kiwi2671]

Andy,
ASME IX QW 409 Electrical Characteristics.
Take SMAW for example (QW 253)
QW 409.1 (Increase in Heat Input) is only an Essential Variable when Impact Testing is required.
QW 409.4 (Change in Current or Polarity) - again only Essential if Impact Testing is required.
QW 409.8 (Change in ampperage and voltage range) is a non-essential variable.
Hope that helps,
Regards,
Kiwi

 

[AndyVictor]

Thank you Kiwi,

You are right. But I could not find any clear range of values for which each pqr is valid without need for requalification. eg. , Suppose current used in a procedure qualification is ~142A, how much more or less I can go for the WPS - Can i have 130A or 150A??. Hope my doubt is clearer now - Does any article in Sec IX (or any other code)give the range of values for these variables(when they are applicable).

Regards

 

[weldtek]

Andy,
D1.1 places a tolerance on certain parameters such as volts, amps, etc. See Table 4.5
For the processes most commonly used in fab shops, Sec IX does not. It does however, restrict heat input for impact tested applications. In those cases though, it's a max threshold for heat input that must be met. In these cases actual volts, amps ( wfs) and travel may vary, but, total heat input must stay at or below that qualified.
I should mention too that SEc IX also has restrictions on heat input for the first layer of weld overlay.

 

[AndyVictor]

Thank you, Weldtek.

It clarifies my doubt and gives me some lead to follow.

Regards

 

[261073eam]

From my point of view, if you take into account the most critical welding parameters carfully during PQR qualification, you dont need new PQR. Weld practics are necesary to qualify WPS and sense to farther aplications, i guess:

If you qualify by 5G/3G, take parameters at 0º, 90º and 180º as must as you can; try to introduce different filler diameters during fill past to obtain higher electric range, test control prior to qualification, etc.
Qualifing a PQR by BW/3G/5 mm/2"/GTAW(t=2mm)+SMAW(filler diameter 2,5mm), will be difficult to welding control on plate/2G/10mm(GTAW+SMAW(3,2mm).

Regards

 

[AndyVictor]

For normal requirements your view is valid. But as per Sec IX, if impact testing is required, heat input (a supplimentary esssetial variable) becomes essential and will be required to be controlled. That means any variation from the qualified value(range) will require requalification.

Regards

 

[stanweld]

Welds not subject to impact testing and corrosion resistant weld overlays are not subject to volt/amp limitations in the PQR per ASME IX.