WPS thickness range ASME B31.3 Table 323.3.1 or ASME IX QW-403.6 1

[nacer16]

Hi everybody,

Question is determination of WPS thickness range.

PQR
Pipe type: A 333 Gr6
Thickness T: 3.76 mm
Impact test requirement: YES according to design code ASME B31.3
Welding Process: GTAW
----------------------------------
So, the WPS min/max thickness range qualified shall be?

1. According ASME B31.3 Table 323.3.1
t/2 to t+6mm?

1.88 (3.76 /2) mm to 9.76 (3.76 + 6)mm

or

2. According to ASME Section IX QW 403.6 and QW-451.1?
QW-403.6 - “However, where T is 1/4 in. (6 mm) or less, the minimum thickness qualified is 1/2T”
QW-451.1 - 1.5 to 2T

1.88 (3.76 /2) mm to 7.52 (3.76 x 2)mm

or

3. Another range

Please, help with your response and explanation.

Thanks in advance.

 

[DekDee]

nacer,
The fabrication code (B31.3) can make requirements more stringent than the qualification code (ASME IX) but cannot make requirements less stringent.
ASME IX takes precedence here.
1.88 to 7.52 mm
Regards,
Shane

 

[nacer16]

Hi DekDee !

That's what I thought. But I preferred to ask the question to have other opinions.
Thank you for your answer.

Best Regards

 

[ZHA]

Refer Interpretation 4-17.January B31-85-031 which says B31.3 thickness limitations takes precedence over ASME Sec IX

 

[DekDee]

HMN,
Welding procedures are qualified in accordance with ASMEIX, not B31.3.
The comment you made is where B31.3 has imposed stricter guidelines than ASME IX - that is perfectly acceptable.
eg.10 mm coupon - max to ASME IX is 20 mm but B31.3 restricts it to 16 mm
But B31.3 cannot and would not allow welding on a thickness greater than what is the qualified range of the ASME IX WPS.

The code will be changed shortly to bring B31.3 in line with ASME IX so there will be no more arguements over this issue,
Cheers,
Shane

 

[XL83NL]

DekDee, do you by any chance have a ballot number which is related to your comment?

The code will be changed shortly to bring B31.3 in line with ASME IX so there will be no more arguements over this issue

 

[DekDee]

XL83NL
11-952
Clarification of terminology ongoing but pretty sure it will be in next code edition,
Cheers,
Shane

 

[XL83NL]

Thanks DD, just send you an off-topic email.

 

[Ishack]

ASME Sec IX qualifies base metal thickness qualified range from 1.88 mm to 7.52 mm (consider only table QW 451) and ASME B 31.3 is bound to use ASME Sec IX code for qualification. Thickness beyond 7.52 mm requires re-qualification.

However ASME Sec IX takes least precedence than construction code. ASME B31.3 specified thickness range from T/2 to T+6 (which is 1.88 mm to 9.76 mm in this case) only when impact test requirement is imposed provided the requirements of ASME Sec IX for PQR testing is met. ASME B31.3 allows the above range without the re-qualification of IMPACT TEST, not the other mandatory test (TENSILE AND BEND) as required by ASME Sec IX i.e the thickness above 7.52 to 9.76 mm doesn't require impact test, however does require mandatory tests as required by ASME Sec IX.

Always the essential / supplementary essential variables as per ASME Sec IX to be followed as it allows those range after the successful mandatory test until and unless your construction code / project specification amend any of those variables explicitly.

The interpretation provided by HMN is not applicable here as the question in the interpretation is referring to QW 403.6 only. The below interpretation gives more clarity on what I have explained above.

Interpretation: 15-23
Subject: ASME B31.3-1996 Edition, Table 323.3.1, Impact Testing Requirements for Metals
Date Issued: October 30, 1996
File: B3 96-044
Question: In accordance with ASME B31.3-1996 Edition, when qualifying welding procedures
which require impact testing, is the thickness range qualified to T/2 to T + Y4 in. rather than the range
given in ASME Section IX, QW-403.10?
Reply: Yes, provided the criteria and thickness limits specified in ASME Section IX, para. QW-
403.10 are not exceeded. See ASME B31.3, Table 323.3.1, box A-5.

Conclusion: ASME Sec IX thickness range mentioned in QW-451 to be followed. Only B31.3 thickness range to be followed for the purpose of selecting test coupon for impact testing.