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UT in lieu of RT 1
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Phased Array is a form of Shear Wave UT which utilises many different angles of Shear in a 'Phased Array'.
The results give a graphical illustration through the weld in many formats, A, B, C & D Scan.
It is semi mechanised and can be fully mechanised, you get a set of results which include a Datum so re-scanning the same weld days/months/years later gives very accurate monitoring of any defects noted.
PA is slowly catching on in the North Sea Oil & Gas Industry.
The results give a graphical illustration through the weld in many formats, A, B, C & D Scan.
It is semi mechanised and can be fully mechanised, you get a set of results which include a Datum so re-scanning the same weld days/months/years later gives very accurate monitoring of any defects noted.
PA is slowly catching on in the North Sea Oil & Gas Industry.
Hold on guys,
the OP asked about UT in lieu of RT for Div 1 work. See CC 2235. It's very involved and expensive. Trust me on this I've been through it several times. I'm not saying don't do it b ut I am saying understand the requirements before you decide.
the OP asked about UT in lieu of RT for Div 1 work. See CC 2235. It's very involved and expensive. Trust me on this I've been through it several times. I'm not saying don't do it b ut I am saying understand the requirements before you decide.
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fleischfresser
Mechanical
Hi,
CC2235 was incorporated in ASME VIII/1 Edition 2010 Addenda 2011 with a reference to the applicable paragraph of ASME VIII/2, 7.5.5.
This paragraph referenced ASME Section V Article4 including Appendix VIII and IX. Therefore in addition to the requirements of Table T-421 the requirements of and Table VIII-421 shall apply.
That means either Phased Array or Time-of-Flight-Diffraction (TOFD) UT are permissible as long as the Scanning technique is automated (AUT) or semi-automated (SAUT).
In addition please find below two Interpretations to CC2235:
Interpretation: VIII-1-98-41
Subject: Section VIII, Divisions 1 and 2 (1998 Edition); Code Case 2235
Date Issued: September 4, 1998
File: BC98-327
Question: Is it permissible to use the Ultrasonic [highlight #FCE94F]Time-of-Flight-Diffraction (TOFD[/highlight]) Technique when implementing Code Case 2235?
Reply: Yes.
Interpretation: VIII-1-07-68
Subject: Code Case 2235-9
Date Issued: January 5, 2009
File: 08-1260
Question (1): Does Code Case 2235-9 require an ultrasonic examination plan capable of detecting indications transverse as well as parallel to the weld centerline?
Reply (1): Yes.
Question (2): Are the acceptance criteria specified in Tables 1, 2, and 3 of Code Case 2235-9 applicable to indications oriented transverse as well as parallel to the weld centerline?
Reply (2): Yes. Per para. (c), the ultrasonic examination shall be performed in accordance with a written procedure conforming to the requirements of Section V, Article 4. T-472 of Section V, Article 4 identifies examination requirements when using the Distance Amplitude Technique, such as Linear [highlight #FCE94F]Phased Array ultrasonics[/highlight], and T-474 covers Non-Distance-Amplitude Techniques. From T-472, weld joints shall be scanned
Regards - Juergen
CC2235 was incorporated in ASME VIII/1 Edition 2010 Addenda 2011 with a reference to the applicable paragraph of ASME VIII/2, 7.5.5.
This paragraph referenced ASME Section V Article4 including Appendix VIII and IX. Therefore in addition to the requirements of Table T-421 the requirements of and Table VIII-421 shall apply.
That means either Phased Array or Time-of-Flight-Diffraction (TOFD) UT are permissible as long as the Scanning technique is automated (AUT) or semi-automated (SAUT).
In addition please find below two Interpretations to CC2235:
Interpretation: VIII-1-98-41
Subject: Section VIII, Divisions 1 and 2 (1998 Edition); Code Case 2235
Date Issued: September 4, 1998
File: BC98-327
Question: Is it permissible to use the Ultrasonic [highlight #FCE94F]Time-of-Flight-Diffraction (TOFD[/highlight]) Technique when implementing Code Case 2235?
Reply: Yes.
Interpretation: VIII-1-07-68
Subject: Code Case 2235-9
Date Issued: January 5, 2009
File: 08-1260
Question (1): Does Code Case 2235-9 require an ultrasonic examination plan capable of detecting indications transverse as well as parallel to the weld centerline?
Reply (1): Yes.
Question (2): Are the acceptance criteria specified in Tables 1, 2, and 3 of Code Case 2235-9 applicable to indications oriented transverse as well as parallel to the weld centerline?
Reply (2): Yes. Per para. (c), the ultrasonic examination shall be performed in accordance with a written procedure conforming to the requirements of Section V, Article 4. T-472 of Section V, Article 4 identifies examination requirements when using the Distance Amplitude Technique, such as Linear [highlight #FCE94F]Phased Array ultrasonics[/highlight], and T-474 covers Non-Distance-Amplitude Techniques. From T-472, weld joints shall be scanned
Regards - Juergen
Fleischfresser,
Thanks for pointing out the fact that the CC has now been incorporated into Sec VIII Div 1. My point is that prior to electing to use the option of UT in lieu of RT the fabricator would be wise to familiarize themselves with all of the requirements including, as you have pointed out, ASME V Art 4 and the applicable appendices. Just the demonstration and calibration blocks are involved and costly. One cannot simply replace RT with shear wave UT evaluated to App 12. I've been through several Div 1 and Div 2 projects using UT and its been, ... interesting.
Thanks for pointing out the fact that the CC has now been incorporated into Sec VIII Div 1. My point is that prior to electing to use the option of UT in lieu of RT the fabricator would be wise to familiarize themselves with all of the requirements including, as you have pointed out, ASME V Art 4 and the applicable appendices. Just the demonstration and calibration blocks are involved and costly. One cannot simply replace RT with shear wave UT evaluated to App 12. I've been through several Div 1 and Div 2 projects using UT and its been, ... interesting.
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