Grinding a weld into acceptance

Date 12-26-2013 17:22

Is a welder permitted to mechanically grind down a weld that that does not meet the acceptance criteria for D1.1 on its weld profile?

On a cyclically loaded structure a welder has laid down several welds that are much larger than what is required and does not display a compliant weld profile. Is he permitted to grind it down and leave it as is without a cover pass? Or does he have to remove the weld entirely and lay down a new one that is compliant? It is my understanding that as long as the weld exhibits no other discontinuities other than poor profile it may be ground down to an acceptable size and considered acceptable. Thoughts?

By Mwccwi

Date 12-26-2013 20:17

Clause 5.26 addresses repair and in a nutshell says exactly that.

By CWI555

Date 12-27-2013 03:57

Unless otherwise specified, the 'cover pass' as you call it would be considered reinforcement. If the weld remained at or above flush, (unless it was detailed with a spec for min reinforcement) no further welding would be required after dressing it to meet surface profile requirements.

The larger picture at play is for what reason could the welder not make the profile requirements?

By swsweld (****)

Date 12-28-2013 04:17

Yes. It's actually required if the reinforcement exceeds the profile acceptance criteria in Figure 5.4.

It could also be advantageous to remove all stress risers and to achieve better UT results if the weld(s) are mechanically ground smooth and no additional cover pass is applied….if those are a consideration.

5.24.4 Groove or Butt Welds. Groove welds shall be
made with minimum face reinforcement unless otherwise
specified. In the case of butt and corner joints, face
reinforcement shall not exceed 1/8 in. [3 mm] in height.
All welds shall have a gradual transition to the plane of
the base-metal surfaces with transition areas free from
undercut except as allowed by this code. Figure 5.4(D)
shows typically acceptable groove weld profiles in butt
joints. Figure 5.4(E) shows typically unacceptable weld
profiles for groove weld butt joints.
5.24.4.1 Flush Surfaces. Butt welds required to be
flush shall be finished so as to not reduce the thicknesses
of the thinner base metal or weld metal by more than
1/32 in. [1 mm], or 5% of the material thickness, whichever
is less. Remaining reinforcement shall not exceed
1/32 in. [1 mm] in height. However, all reinforcement
shall be removed where the weld forms part of a faying
or contact surface. All reinforcement shall blend
smoothly into the plate surfaces with transition areas free
from undercut.

Al, I've graduated from viscous paint to coal tar epoxy coatings to get the "proper" finish on my welds :confused:

By welderbrent (*****)

Date 12-28-2013 13:44

Well, it appears you have your answer, but to put it simply: YES, the welder is allowed to grind down the surface of the weld in order to bring it into compliance. That may be because of roughness, excessive reinforcement, unacceptable weld profile, etc.

Have a Great Day, Brent

By CWI555

Date 12-28-2013 13:16

Al,

Don't forget the bondo before painting.

By Milton Gravitt (***)

Date 12-28-2013 15:12

Yes bondo is good when you put a grinder in someone's hand that don't know how to grind. This might make the Farm Code.

M.G.

By CWI555

Date 12-28-2013 19:39 Edited 12-28-2013 19:54

If I remember correctly, it already has...

Edit, I remember now, page 6 second paragraph.

"When welding tubular structures greater than 15' in diameter, plate preheat shall exceed 2000F if the initial roll of the plate is warped to bring it back intoalignment.
If said tube/can is dropped by the crane, and subsequent dent to large to fill with bondo, repair area shall be heated to 2000F and hammered until it looks like a tortoise shell, fill welded and bondo'd to smooth appearance"

Here is the original thread

http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=77875;hl=farm%20code#pid77875

Attachment: farm_code_20081Draft110-Dec-08.pdf (634k)

By 803056

Date 12-28-2013 19:55

I find it scary that you can quote "The Other Big Red Book" - FC 2002! :roll:

By CWI555

Date 12-28-2013 20:09

LOL. As you stated in the original thread;

"I'm not sure this was a good idea after all. You people scare the hell out of me!;)

You wouldn't be adding to the post if you hadn't seen these practices in the field!

Best regards - Al "

That quote I posted was something I had seen. So which is scarier?

By 803056

Date 12-28-2013 20:12

Better quit while I am ahead. I am ahead aren't ?

Al :confused:

By CWI555

Date 12-28-2013 21:34

LOL, we'll let it rest

By 803056

Date 12-28-2013 19:50

Back in the mid 90's we subcontracted several pressure vessels to a contractor located in the Northeast. They called us to let us know several were ready for final inspection and shipment. They were flawless. No spatter, the paint was smooth and there wasn't any sign of distortion. All the welded were as smooth as a baby's butt.

I looked at the QC manager and said, "This isn't right!"

I started looking around and sure enough they were applying "Bondo" to the entire vessel and smoothing with a straight edge. A little sanding and spraying them down with paint.

They about crapped their pants when I told them to sand blast the vessels to bright metal so we could examine the welds before they were painted as specified in the project specifications. They were not as pretty with the makeup removed.

Al

By Joey

Date 01-02-2014 04:56

If you're doing above ground storage tanks, bondo is consider as "special repair method for temporary repairs"
it says "When deep pits in tank plates are not closely spaced or extensive and thus do not affect the strength of the tank, they may be repaired or filled by a number of methods. Filling with air-hardening adhesive-to-steel epoxies may be suitable if it will not be affected by the tanks contents. Any other material of a putty-like nature that hardens upon drying can be used for temporary repairs"

Happy New Year - 2014

~Joey~

By 803056

Date 01-02-2014 13:40 Edited 01-03-2014 02:13

Above ground atmospheric tanks are a different animal when compared to a pressure vessel. The above ground tank is subject to pressure developed by the static head of the contents. If the content has the same density of water, the head pressure is approximately 1/2 the height of the content in terms of psi, i.e., a thirty foot head would only generate about 15 psi of static head pressure. Petrochemical products with densities less than that of water would produce even less pressure. That being the case, the epoxies my be perfectly reasonable to arrest pit corrosion.

That is considerably different from a pressure vessel that may have to contain pressures many times that developed by static head pressures and elevated temperatures may be part of the operating conditions that must be taken into account. Epoxies probably would not be a reasonable approach to repair weld defects those operating conditions.

Happy New Year.

Best regards - Al

By Joey

Date 01-03-2014 01:20

Quote : Above ground atmospheric tacks are a different animal when compared to a pressure vessel.

:neutral:

What API says "Scattered pits in pressure vessels are best repaired by welding. As a means of temporary repair, proprietary epoxy base materials are available that can be packed into pits to prevent further corrosion" :surprised:

Note: When considering the use of this method, the inspector must be satisÞed that the pits are not large enough or close enough together to represent a general thinning of the vessel component.

:roll:

Pits occurred on welds too. Just want to share with the readers the other use of Bondo. Those are not familiar may under estimate this Bondo when they see it in the possession of contractor. Some may thought the contractor will use it for cheating...that's why the smart storeman :lol:

will not keep the Bondo in storeroom when there is a customer conducting factory audit.

~Joey~

By welderbrent (*****)

Date 01-03-2014 01:35

Interesting.

Have a Great Day, Brent