Fillet Burn Through ASME BPVC Section I

Question

Fillet Burn Through ASME BPVC Section I

B.Westerbeek (Materials)

(OP)

3 May 17 13:07

Gents,

I have a question about a fillet weld burn through (melt through).
We have welded a strip (5 mm thick 16Mo3) to a pipe (60,3 x 4 mm SA-210 grade A1)
During the visual inspection by our client, they discovered a burn through (only a few tenths)

The pipe is a part of a membrane panel (evaporator).
Technically there isn't a issue but our client want us to repair the tube.

I searched in the ASME BPVC section I but it doesn't say anything about a burn through.

Can the customer technically reject our work?

Thanks in advance,

Bas

DekDee (Petroleum) · Answer 1 · 2017-05-04 00:22:57

metengr is the guru on Section 1 so hopefully he will respond.
IMHO the issue (if any) would be the chemical composition of the melt through material.
You have P3 material welded to a P1 pipe - what is the as welded chemical composition and is there a possibility it may react differently with whatever product is flowing through the pipe ?

B.Westerbeek (Materials) · Answer 2 · 2017-05-04 08:56:45

Dear DekDee,

The as welded composition is like 16Mo3 (P3) which is quite common for power plants. The medium is demineralized water / steam.
Furthermore the fillet weld has been qualified by a but weld (SA106 grade B to 16Mo3).
So the burn / melt through is covered by a valid PQR.

I don't see why the tube should be repaired.

DekDee (Petroleum) · Answer 3 · 2017-05-04 11:12:07

Bas,
After I made my original post I had a couple of thoughts - why did you burn through ?
1 The variables (amps/volts/travel speed) listed on the WPS (I presume you had a fillet weld WPS ?) were incorrect for the thickness being welded.
or
2 The welder did not follow the variables listed on the WPS.

Either of these are legitimate reasons for the client to reject the weld/s,
Regards,
Shane

metengr (Materials) · Answer 4 · 2017-05-04 15:09:27

Section I does not address melt-through of a backing strip on an attachment or butt weld, as long as the melt-through does not create excessive penetration.

mk3223 (Mechanical) · Answer 5 · 2017-05-05 21:16:27

The weld defect can cause a potential failure after in the water/steam service. I don't know how the Owner will accept the new equipment without repair.

B.Westerbeek (Materials) · Answer 6 · 2017-05-07 09:44:19

Dear DekDee,

The burn through is probably induced by spacing between the plate and the pipe. Due to this the welding speed has been reduced and resulted in the burn through.
Regarding the heat input isn't a essential but a supplementary essential.

@ mk3223, what about the circumferential (butt) welds in the tube, they can also be a potential failure.

I talked to my authorized inspector and also he sees no reason to disapprove.

viper3982 (Mechanical) · Answer 7 · 2017-05-08 15:42:18

Keep in mind that the customer has the prerogative to reject your work if they want to. We often get customer inspectors that reject stuff that our ASME inspector buys off on. In the end, you can't sell it to the customer if they don't accept it.

mk3223 (Mechanical) · Answer 8 · 2017-05-08 23:40:37

If the "burn through" welds can be approved and accepted, then there is no issue. I am not aware if the Code specifically mention it and is okay with it. And, a pipe can be failed potentially if it has a circumferential weld (butt weld) with defects, such as lack of fusion or penetration.

metengr (Materials) · Answer 9 · 2017-05-09 17:31:20

This is not a Code issue. It may be a contractual issue because the Code is silent on this.

gtaw (Structural) · Answer 10 · 2017-05-28 07:20:18

Unless the project specification includes additional criteria, i.e., melt through, undercut restrictions, etc. for attributes not addressed by the code, I don't see where the customer has a leg to stand on if the weldment meets the code requirements.

Generally, the customer can't unilaterially make up new rules as the project progresses.

Best regards - Al

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Fillet Burn Through ASME BPVC Section I