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swhove (Structural) (OP)
22 Feb 12 12:56
I need some help with a reviewer comment that I received on a 5/16" weld along the length of a 3/8" thick angle.  The comment is "verify that the 5/16" fillet weld will fit considering the toe fillet radius at the end of the 3/8" thick angle".

I have never heard of this being problem and have always used AISC specification J2.b that states for thickness over 1/4" inch max weld size is thickness minus 1/16".  Am I wrong here?
connectegr (Structural)
22 Feb 12 14:34
This is not a fit-up or fabrication problem.  This is done frequently with connection clip angles and many other welded angle details.   

http://www.FerrellEngineering.com

StrPE (Structural)
22 Feb 12 14:53
Agree, not a fit issue.  The 1/16" limit is primarily for 2 reasons. One the get an inspector a visual edge by which the check the weld, and two to minimize weld undercut during the welding process.  Radiused edge is not that severe.  Code say t-1/16" period, not t-1/16" except at angles.
Helpful Member!  Duwe6 (Industrial)
22 Feb 12 17:20
The Detailer is showing experience gained from a previous painful experience.  Angles are rolled products.  Some mills roll 3/8" angle with a full 3/16" radius aross the toes.  If that full-radius angle arrives on site, it will be very difficult to put an honest 5/16" weld on that rounded edge.

When I wear my CWI hat, and find over 10% of the length of numerous welds undersize, I call the Engineer of Record.  If he says that a full 5/16" is necessary [and he ALWAYS does, not wanting to recalculate anything], there will be a WHOLE LOT of Ironworker welders doing a whole lot of remedial work on those welds.  It will take 2 [or more] weld passes to build up the fillet up and around that 'bull-nose' to get the fillet up to 5/16".
chicopee (Mechanical)
23 Feb 12 9:15
Reading the OP makes me remember that when we welded stiffeners or gussets on iron angles these reinforcements were always notched or chamfered near the intersection of the gusset plates and inside raduii of the iron angles.  The welding along the legs would start about 1/16" from the leg edges and end at the start of the chamfers.  We would never weld up to the inside corner of the iron angles.
dhengr (Structural)
26 Feb 12 15:02
That is an absolutely legit. comment on that weld call-out.  Draw two full scale details of a 5/16" fillet; one to the square edge of a 3/8" plate and the other to the toe of your angle with a significant radius at the toe.  In the first case both legs can be 5/16" and the throat is a full (.707)(5/16") in size; while in the case of the angle toe, that toe leg will be much less than 5/16", so you won't get the full .22" throat without a two pass weld.  The reviewer is calling this to your attention, and/or asking do you really need that full throat if you sharpen your calculating pencil.
ToadJones (Structural)
27 Feb 12 0:06
Question really boils down to, can the 5/16 fillet be achieved in one pass for this weld?
I don't know the answer.
Many assume that the largest single pass fillet weld is 5/16" of an inch. This is not always true. In some positions a 3/8" fillet can be done in one pass.
The 5/16" rule of thumb comes about because it can be done in any position.

The reviewer also needs to sharpen his pencil as well.
Together you should be able to come to a consensus.  
Helpful Member!  gtaw (Structural)
27 Feb 12 19:59
I have some news for a few detailers with regards to the size of a fillet weld that can be deposited in a single pass.

I once asked one of my professors why engineers and detailers always specified 1/4 inch and 5/16 inch fillet welds. His reply was because the 1/4 and 5/16 inch fillet welds could be easily deposited as single pass fillet welds.

News Flash: That may have been true when I was still burning rod on the production floor and SMAW was still king of the hill. We used to burn 3/16 and 1/4 inch electrodes day in and day out in the flat and horizontal positions. 1/4 and 5/16 inch fillet welds were the norm for the process and the diameter electrodes in use at that time. The current situation is that few fabricators are still using SMAW for production welds. GMAW and FCAW have replaced SMAW in most fabrication shops. The diameters typically seen on the production floor are 0.045 for GMAW and 1/16 inch diameter for FCAW. You cannot deposit a 5/16 inch single pass fillet with the small diameter electrode that is common on today's fabrication floors without manipulating the electrode, i.e., using a weave bead technique. The problem is that the majority of the welders cannot deposit the large single pass welds without one defect of the other. The most common defects I see are either incomplete fusion at the root or overlap at the horizontal toe (often accompanied by undercut at the upper toe).

Most fabricators only test welders on grooved plate because the groove plate test qualifies the welder for both groove welds and fillet welds. Unfortunately, when these same welders are tested using a simple fillet break test, the majority of them fail the performance test. The test results indicates very clearly that a single pass fillet weld with ¼ inch or 5/16 inch legs is difficult to achieve using small diameter electrode common to GMAW and FCAW.
  

Best regards - Al  

connectegr (Structural)
27 Feb 12 23:04
gtaw
I have been instructed unanimously by all our fabrication clients that 5/16 fillets are completed in a single pass.  Although my personal welding experience was with SMAW, I agree that GMAW and FCAW is the standard practice today.  Most of our work is large commercial and industrial construction.  Perhaps our clients select a larger diameter electrode as a minimum, since the minimum structural weld used is 3/16 fillets.  I have often been told that the minimum 3/16 fillets  can be more difficult than the larger single pass welds.  I am familiar with the problems you mentioned from weave patterns.  

As time passes my experience is becoming more theoretical/technical and less practical.  I appreciate your practical input.  Am I being mislead by my fabricator clients?  Our intent is to maximize fabrication efficiency and economy, this can make a big difference.   

http://www.FerrellEngineering.com

REGRUMBLE (Structural)
28 Feb 12 11:50
I think gtaw needs to get up to date. We have used .045 GMAW or FCAW for years to produce 5/16" or 1/4" fillets. This is very common on both CWB and ASME approved procedures. Weld failure rates are higher using faster processes than the much slower GMAW but if you are going to be competitive in to-days market you better put down a lot of 5/16" with a single pass.
gtaw (Structural)
4 Mar 12 20:43
My comments are based on qualifying many welders for many years. Too many years to admit to.

I have found the problem to be so pervasive that I include a requirement in the project specification that all welders pass a simple fillet weld break test. The test consists of a single pass fillet weld with a 5/16 inch leg with a stop and restart about midway along the length. The ends of the test sample are cut off and the remaining 6 inches fractured through the root.

My experience with groove welds is that about 85% of the experienced welders pass the grooved plate test. My experience testing welders with the simple fillet break test is not as good. The failure rate is on the order of 85%. In some shops the failure rate is higher yet, approaching 95%.

Even when the welder shows me a copy of his/her qualifications for a grooved plate, I still require the fillet break test. The failure rate should be cause for anyone to take notice.

If you have a fabricator that insists there isn't a problem with single pass fillets using small diameter electrode, let them show you by having a few welders, selected at random, weld a couple of T-joints. It they know what they are doing it will take about fifteen minute to weld and break. You don't have to cut the ends off, just weld and break. A quick check of the root (they are required to have fusion to the root, but not necessarily beyond) is one attribute you are looking for. You are also checking to see they have good starts and stops, i.e., craters filled to their full cross section, legs that are nearly the same dimension (5/16 inch is the required size), a weld face that is not excessively convex or too concave, slag inclusions that exceed the allowable, etc.

As I said, the test shouldn't take more than fifteen minutes start to finish. If they pass on the first attempt, keep that fabricator. When they fail, and I put my money on they will fail, you have a good reason to ask them to requalify all their welders using the "simple" fillet break test.
 

 

Best regards - Al  

Duwe6 (Industrial)
5 Mar 12 13:14
Actually, the great preponderance of fillet failures are due to that damnable Short-Circuiting Mig/MAG -- GMAW-SS.  If the welder turns the wire feed up 10Amps, or turns the voltage down 1Volt from a 'cold' no-undercut setting, he is no longer welding.  He is laying down a good-looking, high-temperature braze.  Lots and lots of Lack-of-Fusion.

To ensure this doesn't happen, switch to metal-cored wire, or FluxCore with shielding gas -- FCAW-G.  Or fire all your 'average' welders and only keep the excellent ones [and expect to pay $$$].*

Short-circuiting transfer leaves your out-the-door quality at the mercy of your worst welder.

*Everybody is hiring 'excellent' welders.  Everybody.  If you are stingy with the $$, I'll take that guy away from you for $$$.  And make money using him/her.  'Cheap' welders are exceptionally expensive due to rework and in-the-field repair backcharges.  Plus your Liability Insurance rates may go up, due to the failure rate.
gtaw (Structural)
6 Mar 12 13:04
Short circuiting transfer is simply another tool that can be used to fabricate metal. It has its place in manufacturing due to its limited heat input. Problems develop when fabricators attempt to use it for applications that are not suitable for GMAW-S.

I've used GMAW-S for many sheet metal applications. It is a great process when it is used for the right application. However, due to the limited heat input, it isn't the best choice for base metals thicker than 1/8 to 3/16 inch or those with high thermal conductivity. There are better choices for base metals that are thicker or require higher heat input.

I do agree that GMAW-S is the source of many fusion type defects. That being said, I can also say that in most situations the problem can be attributed to GMAW-S being used for the wrong application or because the welders have not been sufficiently trained to properly set the equipment to the optimum operating parameters. That's were a good WPS can serve a useful function.
 

Best regards - Al  

REGRUMBLE (Structural)
8 Mar 12 13:01
I agree with gtaw that the simple fillet weld "T" test is a good indicator of both welders ability and settings. I often recommend it to welders and was used by the CWB for years as their tackers test for fitters that do not have a full welding ticket.

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