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Up Topic Welding Industry / Inspection & Qualification / Arc strikes
- - By firstpass (**) Date 11-08-2008 00:32
31.3 has three different divisions of inspection  normal, CAt M and CAT D.

arc strikes.  They are a defect that can cause failure where does the code address them. 
Parent - By 803056 (*****) Date 11-08-2008 05:28
As a third party inspector, the visual attributes listed in the tables of B31.3 are the basis of acceptance or rejection unless there is alternate criteria  listed in the project specifications or the fabricator's quality control manual. If the attribute isn't listed, it isn't to be evaluated as a basis for acceptance or rejection.

As the fabricator's QC, additional attributes may be included in the visual criteria of the company's quality control manual.

As the owner's engineer, it would be wise to review the list of attributes and modify them if necessary to meet your needs or expectations. The owner only get what is asked for and what is payed for and then only if the requirements  and conditions of the contract are enforced.

By the way, don't forget "high pressure" and the additional requirments listed in the applicable section of B31.3.

Best regards - Al
Parent - - By CWI555 (*****) Date 11-10-2008 14:46
para: 344.7 in process:

(g) appearance of the finished joint

This is the closest your going to come to it in the 06 code, and it's a wild card stretch of imagination inspectors should stay away from. It is left up to engineering and contract docs to define what and to what extent to be done with arc strikes.
A blanket statement will not typically work, as B31.3 covers hardenable and non-hardenable material, as well as other considerations.
Parent - - By Shane Feder (****) Date 11-10-2008 20:39
Hi First pass,
I think you will find that the 3 inspection classes in B31.3 are Normal, Cat M / Severe Cyclic / Cat D.
There is quite a bit of information in the search engine, just type in "Arc Strikes".
I think it is the general consensus of the forum that the issue of arc strikes is not dealt with by the majority of the codes but are generally not allowed based on project specifications,
Regards,
Shane
Parent - - By cremx (*) Date 11-15-2008 22:14
Check B31.8-03 paragraph 841.244 it refers as arc burn
Parent - - By 803056 (*****) Date 11-16-2008 19:47
You may be correct in finding "arc burn" in B31.8, but the question specifically relates to B31.3.

The third party inspector has to evaluate the welds based on the welding standard cited.

Best regards - Al
Parent - - By hvymax (**) Date 12-01-2008 15:30
  Arc strikes outside of the finished weld act as stress risers [crack-starters]. D1.1 2006 p202 5.29 states that they >shall< be ground to a smooth contour and checked to ensure soundness. Depending on the application [structural,transverse or parralel stress] and code applied they may or may not be an issue
Parent - - By js55 (*****) Date 12-08-2008 18:09
Every inhomogeneity associated with a weldment is a stress riser. Welds themselves are stress risers, especially at the toes. Porosity is a stress riser. Undercut is a stress riser. Slag inclusions are stress risers. Insufficient penetration is a stress riser.  Thickness transitions are stress risers. Phase changes are stress risers.
And I do believe that more failures have been associated with thickness transitions, undercut, high entry angle weld toes, and phase changes, than arc strikes. This may be why, though I certainly don't know for sure, most of the ASME codes don't address the problem specifically. Though they do address more often thickness transitions through envelope maximums, and undercut (especially for fatigue regimes).
Not saying that arc strikes are OK, but my line of thinking may explain (IMO) some of the reticence in the codes, and my thought that we may be practicing a little bit too much handrwringing on this issue.
Parent - By johnnyh (***) Date 12-08-2008 18:16
AKA stress concentrations
Parent - - By whip (*) Date 12-08-2008 04:20
Firstpass, There was an article written not long ago I don't recall if it was in the "Journal" or the "Trends" which went went into great depth from all aspects of just how harmful the metal that is left behind from an arc strike actually is. "When I find it I will let you know" With that knowledge tactfully passed along I don't think you will have any trouble getting that ugly habit stopped. Besides when ever someone has left several arc strikes it clearly shows a lack of quality craftsmanship. And everyone will have one every once and a while. And if it's P-91 you just brought yourself a PWHT.

                                                                                                                      Whip
Parent - - By 3.2 Inspector (***) Date 12-08-2008 14:17
And if it's P-91 you just brought yourself a PWHT.

Or less dramatic - grind the area, and check with MT

3.2
Parent - - By whip (*) Date 12-08-2008 23:15
3.2 Inspector,   That would be a far better alternative than PWHT. Truth is winter before last the customer I worked for strictly required that it be PWHT if an arc was stuck anywhere. The customer I worked for last summer required that it be Wet fluorescent Mag. And the last one I was on stated it could be PT OR MT. So I always read the contract because you never know what the man that owns the Pipe will add to or take away from the requirements.

                                                                                                                                                                    Whip
Parent - By 3.2 Inspector (***) Date 12-09-2008 07:46
:)

Usually arc strikes are in the area around the weld, which will be subject to PWHT anyway....

But, yes I agree, the client is the man......its his freaking pipes :)
Have a nice christmas

3.2
Up Topic Welding Industry / Inspection & Qualification / Arc strikes

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