Is Spatter a "Discontinuity"?

Date 11-24-2014 23:04

Good question: it's an observable item on x-ray's Or UT and can obscure NDT methods (like X-ray and UT). Whether it's a rejectable indication or harms your end form fit and function is a question for the engineer on record. We've all seen spatter hastily painted over on some steel frame.

I don't think traditionally spatter is considered a discontinuity as much as it is considered a visual indication. off the top of my head I thought a discontinuity was generally just that, something discontinuous with the weld bead shape or form, like a crack or porosity, I couldn't see spatter being called a discontinuity unless it wasn't removed prior to doing your x-ray or UT test or similar. But honestly it's one of those ones like "why would you shoot a weld still covered in spatter", as it would fail visual testing.

By JeffStankiewicz (*)

Date 11-25-2014 03:51

For D1.1 purposes spatter is not listed as a discontinuity on Table 6.1 for Visual Inspection Acceptance Criteria.

But it is covered in the code under: 5.30.2 Cleaning of Completed Welds. Slag shall be removed from all completed welds, and the weld and adjacent base metal shall be cleaned by brushing or other suitable means. Tightly adherent spatter remaining after the cleaning operation is acceptable, unless its removal is required for the purpose of NDT. Welded joints shall not be painted until after welding has been completed and the weld accepted.

The only other mention I've seen (from other codes) concerns connection plates. No spatter, slag, sharp edges allowed on mating surfaces.

By electrode (***)

Date 11-29-2014 10:16

Apart from the reasonable points already discussed here; I venture to say: "Yes - spatter is a discontinuity.".
And yes - the student's question is a good one, bearing much more than apparently recognisable.
At least in my "welding universe", primarily not being part of any codes or standards.

By Superflux (****)

Date 11-25-2014 04:54

Then if not addressed on the welding specs, it often becomes a surface preparation issue for the NACE inspector.

By 803056

Date 11-29-2014 14:49

If NACE is invoked.

Al

By 46.00

Date 11-25-2014 07:25

Would you send out a job with spatter on it?

By Lawrence (*****)

Date 11-25-2014 12:33 Edited 11-25-2014 12:35

This is what D1.1 says about spatter and discontinuities:

Annex K spatter. The metal particles expelled during fusion welding
that do not form a part of the weld.

Annex K discontinuity. An interruption of the typical structure of
a material, such as a lack of homogeneity in its mechanical
or metallurgical, or physical characteristics.
A discontinuity is not necessarily a defect.

"5.30.2 Cleaning of Completed Welds. Slag shall be removed
from all completed welds, and the weld and adjacent
base metal shall be cleaned by brushing or other
suitable means. Tightly adherent spatter remaining after
the cleaning operation is acceptable, unless its removal
is required for the purpose of NDT. Welded joints shall
not be painted until after welding has been completed
and the weld accepted."

In the scope of D1.1 I judge spatter to be a discontinuity; and while not a defect, a thing that must be removed for NDT, and in my "opinion" bolting.

46.00 asks a great question.... "Would you send out a job with spatter on it?"

I have this to say about that..."rather convoluted I admit too"
We reduced cost at one plant this year by 36,000 manhours by eliminating people employed full time as spatter scrapers. (We put them to work on value added tasks)
Not by allowing spatter per say, but by tightening WPS controls and making the welders scrape their own spatter. When you scrape your own spatter in enhances the prospect of making a spatter free weld.

Spatter in GMAW/FCAW is usually a sign that the process is not in control. It alerts 3rd party erection inspectors that there may be something more to look at (and they will). Spatter is a sign of sloppy workmanship and while often acceptable, sloppy workmanship has a much bigger effect on the bottom line than the cost of paying attention to detail and making spatter free welds.

By SCOTTN

Date 11-25-2014 13:14

In my humble opinion, it produces a poor appearance and is a sign of poor workmanship. The codes are more tolerant of it than I am, and even AESS welds exposed to view are visually acceptable if they meet AWS D1.1 criteria, unless project specs have a more stringent requirement. In addition to what's already been said by Joel, Jeffrey, Al, John, Glyn, and Lawrence, who have all brought up good points with regard to spatter, I personally think that even tightly adhering spatter should be removed if the member is to be hot dip galvanized, because at some point in service, even the tightly adhering spatter could fall off, leaving spots that are not galvanized, which will begin to rust. The AGA goes on to say that "weld spatter appears to be covered by the galvanized coating, but the coating does not adhere well and can be easily removed." "This type of defect can leave an uncoated area or bare spot if the zinc coating is damaged and must be cleaned and properly repaired."

By Cumminsguy71 (*****)

Date 11-26-2014 11:51

I agree Scott. I have my machine set perfectly for me but due to engineering designs I am forced to use improper rod angle, ok, ridiculously improper rod angles at times and spatter tends to stick. I clean it off even just regular spatter gets cleaned. It looks more professional, it looks clean when the inspector comes. I see spatter as something that will catch your eye, slow you down to look a little closer at things, especially if it's heavy spatter. Just looks like garbage. It might say something about the welders work as well in my opinion. I've seen inspectors fail welds because of spatter and clients call former contract welders "unprofessional" because they didn't clean the spatter.

We're not building Ferrari's but think it all comes down to pride in ones work. Regarding code, I don't have an good answer or interpretation, I just clean it off.

By welderbrent (*****)

Date 11-25-2014 15:12

It depends upon the applicable codes as well as the job specs.

MOST jobs will incorporate SP-2 cleaning for final preparation which will pretty well clear MOST spatter. (as applies to structural applications)

Many good comments as to welding parameters and other cost related applications.

He Is In Control, Have a Great Day, Brent

By jwright650 (*****)

Date 11-25-2014 15:18

just to add some info to Brent's post:

http://www.sspc.org/sspc-sp-2-hand-tool-cleaning.html

By welderbrent (*****)

Date 11-25-2014 23:13

For reference I included a basic description of SP-1, 2, & 3 for those unfamiliar with the process. John's link gets a basic as well, but only for SP-2. Notice the 'Note' at the end of SP-1.

B. Solvent Cleaning (SSPC-SP-1): all materials will be solvent cleaned, regardless if they paint or not. All oil, grease, and/or other soluble contaminates which can be cleaned off of the surface of the substrate will be removed by wiping off the surface with clean rags and solvent or power washing with a degreaser/detergent prior to other cleaning operations. (Note: SSPC-SP-1 is part of all SSPC cleaning operations, blasting or non-blasting).

This specification covers the requirements for the solvent cleaning of steel surfaces. Solvent cleaning is a method for removing all visible oil, grease, soil, drawing and cutting compounds, and other soluble contaminants from steel surfaces. It is intended that solvent cleaning be used prior to the application of paint and in conjunction with surface preparation methods specified for the removal of rust, mill scale, or paint.

C. Non-Blast Cleaning (SSPC VIS-3) Photographs shall be used as a supplemental reference with the SSPC standards for hand and power tool cleaned steel).
1. Hand Tool Cleaning (SSPC-SP-2)- the removal of loose rust, loose mill scale, loose paint, and other foreign
Matter, by hand chipping, scraping, sanding, and wire brushing. Adherent material shall be defined as
Material that cannot be lifted with a dull putty knife.

This standard covers the requirements for hand tool cleaning steel surfaces. Hand tool cleaning is a method of preparing steel surfaces by the use of non-power hand tools. Hand tool cleaning removes all loose mill scale, loose rust, loose paint, and other loose detrimental foreign matter. It is not intended that adherent mill scale, rust, and paint be removed by this process. Mill scale, rust, and paint are considered adherent if they cannot be removed by lifting with a dull putty knife.

2. Power Tool Cleaning (SSPC- SP-3)- the removal of loose rust, loose mill scale, loose paint and other loose
Material to the degree specified by power tool chipping, de-scaling, sanding, wire brushing, and grinding.
Adherent material shall be defined as material that cannot be lifted with a dull putty knife.

This standard covers the requirements for power tool cleaning of steel surfaces. Power tool cleaning is a method of preparing steel surfaces by the use of power assisted hand tools. Power tool cleaning removes all loose mill scale, loose rust, loose paint, and other loose detrimental foreign matter. It is not intended that adherent mill scale, rust, and paint be removed by this process. Mill scale, rust, and paint are considered adherent if they cannot be removed by lifting with a dull putty knife.

By Smooth Operator (***)

Date 11-26-2014 00:14

Al, Worked at a structural steel fab. Shop in my early years...... Wasn't " allowed" to clean spatter from the welds (time waster) because the steel was being blasted and painted.........Someone else's problem!!!!!!!!! :confused:

By jwright650 (*****)

Date 11-26-2014 12:03

Smooth Op,
Me too....I worked for a place where the welders didn't clean anything(even though they were the ones who made the mess), they left it for the painting department to clean it up and get it ready to paint, whether shot blasted or hand/power tool cleaned, it didn't matter.
I think it was a decision by the original owner of the company who paid the fitters and welder a higher wage than the painting department workers, so he saw it as a waste of his money to have a higher paid welder scraping and cleaning when he could be welding the next piece sitting on the table.

Al, I agree with you about checking with the customer and the specs that govern the work.....although when I saw lots of spatter during my walk-through, I stopped to see what is going on with this welder's equipment because they knew better. I spent time with them coaching them to setup to produce welds with minimum spatter.

Brent, good job with the cleaning notes....you covered it pretty well. :cool:

By welderbrent (*****)

Date 11-26-2014 15:07

It is out of my QC Manual, don't remember where I lifted it from though I did rework it. Just took the important area for this posting. Didn't want to be in competition with the wall of text masters :lol:

He Is In Control, Have a Great Day, Brent

By 803056

Date 11-29-2014 15:41 Edited 11-29-2014 15:50

I am going to conclude my participation to this particular post with the following comments.

I agree it is a good question, but I find several of the responses from individuals that have inspection backgrounds are based on opinion, personal preference, or limited to a specific welding standard. I find that troubling from the standpoint that as CWIs, our position should be founded on the requirements of the applicable welding standard and the project specification. Applying the requirements of "What I did on my last job" carries little weight, unless the contract imposes the same requirements as the "last job." It is also bad form when the inspector attempts to impose his will or personal preference the contractor.

In one of my examples, the pressure vessel fabricator, their QC department for all practical purposes put the fabrication department out of business because of their insistence that there be "no spatter" inside or out and that all welds be "flawless" to the point where welds were ground smooth for no purpose other than to satisfy the inspector. Hours of labor were wasted cleaning spatter and grinding welds that had no effect on fit or function. The vessels for the most part were installed in the bowels of the factory where they were covered with grease and grime in short order. Do not get me wrong, there were instances where the finish was required to be “flawless.” Equipment purchased by medical and the electronics industries required the vessels to be polished to a mirror like finish inside and out, electro-polished and then passivated. The contract specified the finishing requirements and the customer paid for the additional work required.

In the final analysis, the vessels purchased from subcontractors were accepted as received. The company executive management took the position that if the code did not address spatter and if the customer did not include limitations for spatter, it was permitted. QC still insisted that any vessel fabricated in-house had to be spatter free. The bottom line was that eventually all the vessels were subcontracted and the fabrication of vessels in-house went the way of the Homing Pigeon. The department went from 22 welders to no welder in the course of a few years. The company still sells pressure vessels, but they are all subcontracted. Spatter, it did not matter to the end user. I told the QC manager that he was effectively killing the fabrication department by his insistence that "our" vessels had to be "flawless." We simply could not compete with other fabricators that could meet the code and the contract without the additional labor costs incurred by the needless finishing requirements imposed by QC.

I agree with many of the comments regarding the possibility that excessive spatter is an indication that the operating parameters are out of reasonable ranges or that technique can be improved. I also agree that as inspectors it is our responsibility to ensure the product meets code requirements as well as any additional requirements invoked by the project specification. However, thin ice is being trodden when personal opinion supplements or replaces the code requirements.

Taking the fabricator's position, I will gleefully clean all spatter if that is what the TPI insists upon, but I will be just as happy to track all the extra labor hours and invoice the owner for the additional work. If history is an indicator of the future, it will not be too long before the TPI is replaced with one that limits his activities to what is required by the code and project specifications.

Whether spatter is a discontinuity or defect is the providence of the applicable code and project specification, not the inspectors personal preference. If NACE, AWS D1.X, MIL-STD-2035, in-house quality manual, etc., addresses spatter, it must be assessed and evaluated. Otherwise, it's presence is a non-issue.

I hope everyone had a happy Thanksgiving.

Best regards - Al