CRACKS ON ASTM A 335 P 22 FINNED TUBES

By ranjit menon Date 03-20-2019 16:53

Sirs,

I am not a technical person and it is my first post on AWS. We have recently delivered ASTM A 335 P22 finned tubes to our client. The manufacturer of finned tubes procured bare tubes from the distributors (since P 22 was not easily available and the required quantity was also small) and this was for an ongoing turnaround in the refinery. The manufacturer has conducted hydrotest and PMI and tubes were delivered. However, our client upon visual inspection at site found out multiple cracks on the tubes and they conducted MPI and in situ metallography. They rejected the tubes. The manufacturer maintains the cracks will not cause any issue. However, client informed that finned tubes will be used in a heater having a design temp of 600 Deg C.

Could you anyone advise what might have caused multiple cracks and whether is there any justification for accepting the tubes?
I will sincerely appreciate early response. I will give details of the test and certificates upon request.

Thanks,

By SWN1158 (***)

Date 03-20-2019 17:22

With regard to "multiple cracks on the tube", upon receiving this material from your supplier, before signing the bill of lading, was it inspected to ASTM A335 Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service? And was this spec. noted on the purchasing documents that "this material must meet A335 criteria" ?

A335 states this in paragraph 7...

7. Workmanship, Finish, and Appearance

7.1 The pipe manufacturer shall explore a sufficient number of visual surface imperfections to provide reasonable assurance that they have been properly evaluated with respect to depth. Exploration of all surface imperfections is not required but may be necessary to ensure compliance with 7.2

7.2 Surface imperfections that penetrate more than 12 1⁄2 % of the nominal wall thickness or encroach on the minimum wall thickness shall be considered defects. Pipe with such defects shall be given one of the following dispositions:

7.2.1 The defect may be removed by grinding provided that the remaining wall thickness is within specified limits.

7.2.2 Repaired in accordance with the repair welding provisions of 7.6.

7.2.3 The section of pipe containing the defect may be cut off within the limits of requirements on length.

7.2.4 Rejected.

Furthermore, you mentioned that "The manufacturer maintains the cracks will not cause any issue. However, client informed that finned tubes will be used in a heater having a design temp of 600 Deg C." Is this something that was a requirement in the project specifications, and if so, was this relayed to the supplier?

I have a copy of this spec I can send you if you don't have it. Just pm your email address.

By ranjit menon Date 03-21-2019 02:56

Thank you very much for your swift response SWN1158. It is very much appreciated. The manufacturer has appointed their own TPI and from the tender stages itself manufacturer mentioned that they can do only final PMI test and not any other test. However, they decided to appoint TPI and they conducted hydrotest at 7.5 kg/cm2G. Client never mentioned any specific tests to be carried out on the tubes, but when the order was placed, manufacturer provided ITP and client accepted the ITP. In the ITP it was never mentioned any MPI or in situ metallography test. Also the purchasing documents not mentioned any A335 criteria.

Regarding the requirement client has mentioned that finned tubes are required for heater. It was Finned Tubes for Heater.
Thanks a lot and I have sent my email ID to you

By SWN1158 (***)

Date 03-21-2019 13:37

I just sent it to you.

By ranjit menon Date 03-21-2019 15:34

Thank you very much.