welding procedure qualification
welding procedure qualification
(OP)
I am reviewing vendor's welding procedures on a Vessel, which requires impact test.
The welding process is SAW. The vendor provided two PQR(s) to support one WPS. Impact test is required. ASME IX is used for the qualification.
PQR-1:
Test coupon thickness: 8 mm
Maximum Interpass temperature 311F;
Maximum Heat input: 68000 J/in
PQR-2:
Test coupon thickness: 19mm
Maximum Interpass temperature: 383F;
Maximum Heat input: 57000 J/in
WPS:
Qualified thickness range: 8-38mm.
My quesions:
(1) Which one is the qualified Maximum interpass temperature: 411F or 483F ?
(2) Which one is the qualified Maximum Heat imput: 57000 or 68000 J/in ?
Please advise. Thicks.
The welding process is SAW. The vendor provided two PQR(s) to support one WPS. Impact test is required. ASME IX is used for the qualification.
PQR-1:
Test coupon thickness: 8 mm
Maximum Interpass temperature 311F;
Maximum Heat input: 68000 J/in
PQR-2:
Test coupon thickness: 19mm
Maximum Interpass temperature: 383F;
Maximum Heat input: 57000 J/in
WPS:
Qualified thickness range: 8-38mm.
My quesions:
(1) Which one is the qualified Maximum interpass temperature: 411F or 483F ?
(2) Which one is the qualified Maximum Heat imput: 57000 or 68000 J/in ?
Please advise. Thicks.





RE: welding procedure qualification
1) the highest interpass temperature because one could always decease interpass temperature (see QW-406.3, which would not adversely affect impact requirements. Higher interpass temperature means more heat input and grain growth.
2). Use the maximum heat input value on the WPS because if you increase the heat input, the WPS must be re-qualified (see QW-409) for the same reason as in 1).
RE: welding procedure qualification
Thanks for you comments.
(1) The Maximum Interpass could be 483F(383F + 100F), using PQR-2
(2) The Maximum Heat input could be 68000J/in, using PQR-1.
Am I right?
My concern:
The qualified thickness is only 8-16mm by PQR-1. If the plate thickness used in the fabrication is 24 mm, which is qualified by PQR-2. The maximum heat input of 68000J/in is qualifed by PQR-1. How can I deal with this case? Do you know what I mean? Thanks.
RE: welding procedure qualification
Correct, by Section IX guidelines.
Correct, by Section IX guidelines.
You need to envelope the interpass and heat input, which you have done by the above. I don't see that this is a problem. You can always run a leaner heat input for the thicker production material. You can have the vendor follow the lower heat input requirement because you are not penalized for decreasing heat input.
RE: welding procedure qualification
RE: welding procedure qualification
RE: welding procedure qualification
RE: welding procedure qualification
RE: welding procedure qualification
RE: welding procedure qualification
RE: welding procedure qualification
RE: welding procedure qualification
My point is simply this, in the example above, impact tests are NOT required on the thicker test plate. As I stated in my previous post, per ASME Sec IX, an impact tested only, ( ie no bends and tensiles,)weld coupon on 8 mm plate, combined with a weld test plate on 19 mm tested for bends and tensiles only ( ie no impacts), will support a WPS with impacts, 8 mm thru 38 mm. Of course, max heat input recorded for the impact tested plate governs.
Now, if in fact, both the 8 mm plate and the 19 mm plate were impact tested, the SE variables from the 8 mm plate would govern for thicknesses below 19 mm. Above 19 mm either set of SE variables could be used. Evidently the Sec IX Subcommittee recognizes that when using the same heat input and welding within the range of other variables, thicker base metals typically experience less degradation of notch toughness.