ASME IX Thickness range question 1

[DeanIEng]

Hello one and all,
I have a question regarding the ASME IX code. A procedure is qualified by welding a 6" Sch 80 pipe, wall thickness 0.432" (10.97mm). As the procedure will be used for a pressure application, notch toughness testing is required. QW 403.6 applies in this instance and limits the thickness range for a pressure application to T - 2T, (0.432" - 0.864")

Years later, a welder welds a single test coupon using the same weld procedure but with a 4" Sch XS pipe, wall thickness 0.337" (8.56mm). It is subjected to Volumetric NDE only to qualify it.

Does this additional 4" test coupon need notch toughness testing to allow it to be used in pressure applications, or does the earlier notch toughness testing on the 6" pipe qualify it?

Thanks if you can help,

DeanIEng

 

[weldstan]

The welder is not subject to impact test qualification.
He may weld the thinner pipe; however, a new WPS must be impact test qualified to permit welding the thinner (0.337") pipe per ASME IX.

 

[DeanIEng]

Thank You weldstan, much appreciated!

 

[DekDee]

DeanIEng
Just to clarify (or perhaps muddy the waters)- if you are welding in accordance with B31.3 your original WPS is acceptable for 0.337" WT (with minor revisions),
Cheers,
DD

 

[DeanIEng]

DekDee,
Thanks for helping. Your comment does muddy the water somewhat. How is it possible that the original WPS may cover 0.337"? Is it A-5 in Table 323.3.1 which would qualify the thickness range as
0.216" - 0.668" (5.43 - 17.3mm)?. Also, are there any other "minor revisions" that would apply in order to qualify to B31.3?

 

[weldstan]

B31.3 places different limits for impact test qualification they are T/2 to T + 1/4" where T = thickness of qualification coupon.

 

[david339933]

I know this will open a can of worms, but......

The WPS is not qualified to .337" wall with B31.3 applications:

1.) 328.2 of B31.3 states that WPS shall be qualified to Sec IX.

2.) Table 323.2.2 states the requirements for impact testing.
A-3 of this table refers to Note 2 - which states, Impact testing performed as part of the WPS qualification will satisfy all requirements of table 323.2.2 and need not be repeated for PRODUCTION welds. Key words...production welds.
A-3 also states that impact testing shall be done in accordance with 323.3

3.) 323.3 states that impact testing shall be done in accordance with Table 323.3.1

4.) Table 323.3.1 refers to "tests on welds in fabrication or assembly", in other words "production welds".
A-5 of this table limits the impact testing exemption laid out in A-3 above, to T/2 to T + 6mm.

Therefore WPS is qualified in accordance with Section IX, in this case .432" - .864", however if you want to weld any thickness greater than .432" + 6mm, you require production weld impact testing on that greater thickness. The same WPS is still valid. On the other hand, the minimum is still .432", the WPS is not qualified for anything less.

 

[DekDee]

Sorry David - wrong.

Interpretation: 4-17
Subject: 327.5. and 327.5.2
Date Issued: January 29, 1986
File: B31-85-03

Question (1): When qualifying welding procedures which require impact testing, is the basic qualified thickness range 1/2t to t + 1/4. in, rather than the range given in Section IX of the ASME Boiler and Pressure Vessel Code of the lesser of 5/8 in., and t to 2t as in QW-403.6 (where t is thickness of test coupon)?

Reply (1): Yes.

Interpretation 24-29
Subject: B31.3-2008, Interpretation of Table 323.3.1 Impact Testing Requirements for
Metal
Date Issued: October 3, 2013
File: 13-1549

Question: In accordance with ASME B31.3-2008 edition, Table 323.3.1 Box A-5, is the qualified thickness range T/2 to T + 6mm (1/4 in.)?

Reply: Yes. Also, see previous Interpretation 4-17.

REgards,
DD

 

[DeanIEng]

David 339933, I can understand your confusion. Your view seems to make sense, and I often find myself bewildered by the codes and the interpretations, which sometimes contradict what's written or don't appear to make sense.
There is another interpretation in the B31.3 code, however that further supports DekDee's answer;

Interpretation Number: 15-23
Codebook: B31.3
Volume: 15
Date: 30-OCT-96
Subject: ASME B31.3-1996 Edition, Table 323.3.1, Impact Testing Requirements or Metals
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 + 1/4 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

regards,......DeanIEng