ASME B31.3 thickness Range Issue
limesh M
Dear All,
I want to prepare a WPS,
Design code – ASME B31.3, Welding Code- ASME BPV SEC IX
Material used during PQR - ASTM A 333Gr6 (P No.1 Gr. 1) To ASTM A 350-LF2 (P No.1 Gr. 2)
Thickness of test coupon – 23.8mm
Process – GTAW+SMAW
PWHT – Yes (600⁰C± 10⁰C)
Weld coupon Impact Tested – Yes
I have reviewed ASME BPV 2010 edition, QW403.6 it says “The minimum base metal thickness qualified is the thickness of the test coupon T or 5/8 in. (16mm), whichever is less.However, where T is less than ¼ in. (6mm), the minimum thickness qualified is 1/2T”
Then I reviewed QW.171.1 General.“Charpy V-Notch impact test shall be made when required by other sections.QW171.2 Acceptance.”The acceptance criteria shall be in accordance with that section specifying impact requirements”
Then I reviewed ASME B31.3, 2008 edition Table 323.3.1 Impact testing for materials.
A-5
“(a) One piece, thickness T, for each range of material thickness from T/2 to T+ 6 mm(1/4in.)”
“(b) Unless required by the engineering design, pieces need not be made from each lot, nor
from material for each job, provided that welds have been tested as required by
Section 4 above, for the same type and grade of material (or for the same PNumber
and Group Number in BPV Code, Section IX), and of the same thickness
range, and that records of the tests are made available.”
Bathula Raghuram (Mumbai - PIPING)
You can use this PQR for base metal thickness 16 to 47.6mm, however for the range falling outside B31.3 limits (i.e. 11.9 – 29.8mm), additional PTC shall be tested for CVN impact.
John Henning
Limesh,
A general clarification:
ASME Section IX represents a generic set of rules for weld and weldor qualification. These rules may be further restricted by the fabrication/design Codes that specify qualification in accordance with Sc IX. When additional restrictions (or exemptions for that matter) exist, they take precedence to Sc IX requirements. In this case the qualified thickness rules are more restrictive and will apply in lieu of the requirements provided in Sc IX QW-451.1 and Sc IX QW-403.6. Customer requirements, other Codes or Standards are handled similarly. When you are presented with this situation, it may be beneficial to write multiple WPSs based on the applicable PQR(s) – one or more WPSs for the specific design/fabrication Code(s) incorporating all the additional restrictions and a general WPS meeting the requirements of Sc. IX.
Hope this helps.
John
From:
material...@googlegroups.com [mailto:material...@googlegroups.com] On
Behalf Of limesh M
Sent: Tuesday, September 21, 2010 1:09 AM
To: Materials & Welding
Subject: [MW:7119] ASME B31.3 thickness Range Issue
Dear All,
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limesh M
Dear Raghuram Sir,
Could you please clarify little bit more.
Can I write a WPS showing maximum and minimum thickness range as 16 mm - 47.6 mm as per the current PQR?
If not what would be the minimum and maximum thickness I can write on my WPS with current PQR?
I am looking for the precise range.
Regards,
Limesh
