Cleaning between successive welding beads

[21121956]

Hello everybody:

Please, take a look to this video (Soldadura de penetración tubería de 12") and I will appreciate your comments.

The code AWS D1.1 requires cleaning between each welding pass and it also includes the cleaning between successive beads (that is not the case of the procedure showed in the video where the welder melts around of six electrodes without the slightest intent to apply at least a wire brush).

Under what circumstances is it acceptable the procedure under discusion?

http://www.draftsmen.com/videos-soldadura-de-penetracion-tuberia-de-[ccVfUqnXMgU].cfm

Thanks to all.

 

[Mr168]

Not cleaning between passes is "acceptable" when a) it doesn't violate the code (which in your AWS example, it would), and b) the weld meets all applicable examination criteria.

However, "acceptable" and "good practice" aren't always one in the same. There are plenty of welders who prefer to weld horizontally without knocking off the slag from the previous pass, as the slag can support the puddle in the subsequent pass. It can produce "acceptable" and visually "pretty" welds. However, it's also a prime candidate for lack of fusion and slag inclusions.

While it may not be prohibited by code, it's certainly poor practice in any slag-producing process.

 

[gtaw]

As noted in the post, AWS D1.1 requires the slag to be removed between weld passes. However, the welding depicted in the video clearly isn't required to meet AWS D1.1.

Since the welder is welding pipe using the uphill progression and since it is likely that he is using an electrode type that is a cellulous covered, he is most likely not depositing weld over a bead with slag intact. The E6010 and E6011 type covered electrodes have a relatively light friable slag that would not cover the weld crater of the previous weld bead when depositing weld using uphill techniques.

“Good practice” and obtaining acceptable weld quality do not always go hand in hand. There are occasions when “welder technique” is able to meet quality requirements while being in conflict with generally accepted “good welding practices.”

I would not advocate the welding technique depicted, but it is hard to argue with success if the resulting welds demonstrate the ability too meet the acceptance criteria imposed by the job requirements.


Best regards - Al

 

[Kiwi2671]

As Al has mentioned it definitely isn't AWS D1.1 - possibly API 1104 ?
Normal technique (worldwide) when using cellulosic electrodes in the uphill or downhill direction is to not "feather" the bead with a grinder prior to starting the next bead.
What I saw in the video was a perfectly normal pipeline weld duplicated around the world a thousand times a day.

Kiwi

 

[Duwe6]

Everybody's correct, in my opinion. Refusing to clean is totally unacceptable for AWS or ASME items. It is "usual & customary" when welding downhill on cross-country pipeline to API-1104. However, please note that cross-country pipeline welds are X-rayed at a very high percentage; 100% [every weld] is not uncommon.

 

[21121956]

Hello everybody:

Thanks to all; your comments are highly appreciated.