Preheat and Toe Cracks, Sounds Painful!

We have been welding on a coupler ladder assembly for an ATB. (Articulated tug barge) It veries in thickness from 3"-1/2" up to 9" thick. The coupler ladder is structural casting ASTM A148-90-60 (Ce= 0.69 Pcm= 0.38) and is being welded to ABS Grade A 1"-1/2" plate and also ABS AH36 3/4" plate. The current WPS is for FCAW it states to use filler metal AWS Specification: A5.20 and AWS Classification: E71T-1CDH8 and to preheat to 300* F. We are having some cracking problems on the weld toe to the cast parent metal. On some of the research that I did it states to use an E81T1-Ni1C wire and to preheat to 400*F. In clause 3 of AWS D1.1 2010 on 3.5.1 base metal / thickness combination. (base on the category and thickness) shall be the highest of these minimum preheats. Would you suggest to increase the preheat to 400* F and use the E81T1 electrode?

Best Regards.
Gabriel M.

The 70ksi electrode should work and the 300 degree preheat should be sufficient. You should have a PQR that was used to qualify these materials. If you do not then you should start there.
My experience with preheat...
When a 300 degree preheat is required keep in mind that the measurement to deturmine if the preheat's been met would be a minimum of 3 inches from the weld. That's 3 inches or the thickness of the material, which ever is more. You mentioned 9 inch material. That preheat would need to be measured 9 inches from the weld.
With toe cracks in high strength material (that A148 is a Class 3) I would suspect preheat and more then that, I would suspect a preheat that is not being applied the full material thickness distance.
PWC

Those Canucks take their welding seriously

Paul,

I know what you're thinking, another early Saturday morning question.

I've been looking at the requirements of obtaining a CWB inspector certification. Am I seeing this correctly? A CWB inspector can apply for a CWI by reciprocity by nothing more than an application and fees. But a CWI who wants to be a CWB, in this case a level 2, would fill out the application, pay fees, and still have to take an exam?

Doesn't strike me as "equivalent" or fair.

Tim C. CWI, CWE

Level II VT, PT, MT, UTT

Tim,

Your assessment is correct.   For a CWB to apply for a CWI it’s just a fee and some paperwork.  For a CWI to apply for a CWB it’s a test.  Those Canucks take their welding seriously.

I was the Quality Manager in a pole manufacturing company that was CWB Certified.  Every 6 months I had to hire a CWB engineer to audit my organization (and it was an in-depth look at our welding).  There were a lot of hoops to jump through, but if we wanted to sell power-line poles in Canada it was a requirement.

I was also a contract CWI for a boss that was Canadian.  Anytime I mentioned my past work as a Welding Engineer he would go ballistic.  Calling yourself a Welding Engineer in Canada means you’ve met specific requirements in education and testing and if you referred to yourself as a Welding Engineer without meeting those requirements you could go to jail.

Some of the things I liked about working in a CWB shop: 1.) Welders had to retake their Welder Qualification Tests every 2 years.  I believe that helped maintain weld quality in our shop. 2.) Welder Qualifications were given using a Bevel Groove.  The first pass was a Fillet Weld of a specific size up against that square edge of the Bevel Groove.  The fillet had to have a restart in it. The location of the restart was marked, and 1 of the 3 required bend coupons had to contain that restart.

One of the things I didn’t like was that they consider FCAW and GMAW with a Metal-Cored wire (MCAW) the same process (for welder qualification purposes).  The Welding Engineer in me (said quietly so as not to be heard across the MN/Canadian border) sees these processes as requiring different skills.

When working in a shop that requires compliance to CWB and AWS this FCAW/MCAW thing reeks havoc.  In fact, when I showed up for my first week at this pole shop I learned that All of the Welders took a FCAW test to get their job, but the shop ran about a 50/50 mix of FCAW and GMAW using Metal-Core.  From a CWB perspective this was no “Biggie”, but from an AWS perspective (which was about 90% of what they did) no Welders were qualified for GMAW (and not one of the 4 CWI’s that worked there seemed concerned).  What a mess!

The way I turned that around was by using the CWB 2yr retesting requirement.  I gave MCAW tests, had them evaluated by the CWB to Canadian standards and evaluated them myself as a CWI to AWS standards.  At 6 month intervals, over a 2 year period, those Welder Qualifications were brought up to speed.

If I was an independent contract CWI I’d probably pursue the CWB route, but if you work in a shop that’s considering bringing in CWB work then CWB/CWI reciprocity is the least of your worries.

PWC

Fillet Welds on Corner Joints

Hello,
I have a question regarding D1.1 code.
My question is regarding the corner joints in the plates encompassing the columns. They are calling them Fillet welds, yet there is not any faying surface. D1.1 says a fillet can have up to 3/16ths misalignment (with certain stipulations) which is effectively is making the joint an open root CJP.

They are using a ceramic backing that (desired because of the tight fit around the square column plus the misalignment) is reducing the theoretical throat greatly. Now they are having substantial issues with cracking threw the throat, which isnt surprising.

My issue though is with the joint design; Im inclined to say it is not a fillet weld, but I cannot find a code reference to support that claim. And I cannot find a prequalified wps and joint config that in any way resembles this joint PJP or CJP groove.
Am I missing something in the code that resolves this? Specifically any denominational requirement for the length of faying surface on fillet welds? What course of action would you advise?
Thank you for any assistance,
- Caleb

Caleb,
I'm not sure of the plate thickness, it looks (from the photo) to be about 3/8”. If that's the case these 1/4" welds are undersized. That said:
This is a common Fillet weld on a Corner joint. If you have a copy of AWS D1.3 Fig 3.2a you'll see a picture of it.
Questions I would ask…
Does the shop/contractor have a WPS for welding this?  The fillet looks to have been done vertically down. This would require testing. What is the process used?  It looks to be GMAW-S. If so, this would require testing also.
I'm sure your cracking is due to insufficient throat. You can fix that by requiring multiple passes.
Here's where you should go with this…
Ask about the WPS and the process. If they are not in compliance, take out a rubber hose and beat them until they are (that’s a metaphor for fix that first 😊).
Ask the engineer to change the weld call out to:
Weld size = T (remember, T is thickness)
Require a Convex contour (that will insure the throat size)

That should do it.
PWC

Repair WPS

Paul,

When codes refer to a company having a "repair WPS", are they saying that a different test needs to be qualified other than the procedures that have already been qualified?

If this is the case, would you record the NDE, hold points, etc. that are required in the WPS? Sort of like, these are the steps and sequence of events that are required to take place.

 

Timothy C. CWI, CWE

ACCP Level II VT, PT

ASNT TC-1A Level II MT, UTT 

P.S, Thanks for the time you've taken over the years to let us ask, argue, talk through, and debate all the issues we come across. It only makes us better at what we do.

Tim,

And all this time I thought I was the only one that would get up at 6am on a Saturday with welding on the brain (I happened to be calibrating my UT scope when I got your email).

Let me concentrate on your first question as it would relate to AWS D1.1 (because you are right, the Bridge Code is more specific).

D1.1 requires a repair WPS, why would they state that? 

In most manufacturing environments we would have specific WPS’s for specific joint configurations, materials, positions welded… Let’s imagine the company "PWC Weld-All" had WPS's for all position, unlimited thickness, Base Metal Group 1 & 2 for Lap, T- (fillets & grooves), V-, Bevel and Square Groove Joints.  Your first impression would be that PWC has his shit together, right?  Now let's say PWC hired his brother (because his Mom made him) to punch bolt holes in steel with an Iron Worker.  Who could mess that up?  Well, his brother did and now you’ve got four 1- inch holes in the web of a S24x100 I-Beam.  The customer insists they be filled.  Which WPS will cover this repair?  Since the joint configuration now is a hole in a plate none of the existing WPS's will apply.  A new WPS will need to be developed which may or may not require testing (dependent on code requirements).

Here's another scenario… The base plate of a light pole tower is welded using FCAW-G.  While being erected the customers inspector finds unacceptable porosity and requires a repair.  That repair could be made using the same procedure used to manufacture the tower, but it wouldn’t be practical to use FCAW-G, in the field.  A procedure would need to be written (and possibly qualified) to complete this repair using another process (FCAW-S or SMAW). 

One last scenario… A crack in a weld is discovered in a Bevel-Groove.  The engineer determines it can be repaired.  This can typically be done using the original WPS.  While excavating you find this crack extends into base material.  Now your joint configuration will probably be outside the tolerances of your WPS, so another WPS will need to be written (and possibly qualified).

Often times the PQR's you've previously completed will cover the repair WPS, but you still need to write the new WPS. 

As the engineer I have written many repair WPS's.  When I do I will put language in there that is not typically found in a production WPS.  Things like, “Drill a X/X diameter hole at each tip of the crack to reduce the chances of growth.”  or, “Once  discontinuity is removed PT to insure its complete removal.” or, “MT each weld layer to insure soundness.” or “Never let my brother touch that machine again.”

So your repair WPS isn't anything different then any other WPS, you just want to insure that you've covered all your bases in regard to material, joint configuration, position before moving forward with the repair.

Ask me the time and I build you a watch.  Sorry about that.

PWC

Maybe B2.1 is the better choice...

 Hey Paul,

 It’s Kody P.  I was in your Minneapolis seminar, I was wondering if you would be willing to get me pointed the right direction for a PQR/WPS testing of pipe/tube to plate for fillets and PJP groves in AWS-D1.1?

The pipe/ tube is “unlisted” material of the following specs: A519 1026, A519 1026cw, A519 1026hr, A513 1026, A513 1026cw, (min yield is 35ksi – 70ksi grade dependent).  All are not pre-qualified or listed and the rings will be A36 or some grade of A514.  Size ranges from 2” OD tube 3/16 wall with 1/8” fillet and bevel to 20” + OD 2” wall with up to 1 ¼” fillet / bevel.  Plate ranges from 3/8” to 2”+

I know I need to do macro etches but I am a little confused as to how to get the tensile specimens /side bends for the sizes we are working with.

As of right now my thoughts are to purchase some large od tube/pipe and use that to cut coupons from to do 1G test plates to prove the process, Then do the fillets/PJP etches. If both are successful I could use both PQR’s to make a WPS and repeat for all combos. But then at that point should I use AWS-Fig. 4.10/4.11 or 4.23 for the 1G test set up?

Any thoughts or advice would be appreciated

Thank you

Kody P. Lead Inspector

Kody,

It’s amazing what you run into, isn’t it?  My first WPS experience as a “green” CWI was insuring the company I worked for met all the requirements to weld carbon and stainless to ASME.  Something I had zero experience with.  (I learned a lot… one mistake at a time)

First thing I would do if I were you would be to group the A519 grades and the A513 grades (what do I mean by that?).  Just find some A519 Grade 1026 and some A513 Grade 1026 (forget about those additional designators, they don’t amount to enough to matter.).

Next: Get yourself a copy of AWS-B2.1 Specification for Procedure and Performance Qualification.  In it you’ll find that the AWS groups your A519 into Group 2 and your A513 into Group 1 (or visa-versa, I don’t remember which).

Now…

This group of PQR's could get extremely complicated if you qualify to D1.1, so don’t.  Qualify to AWS B2.1 and just state that on your documentation.  Qualifying to B2.1 can be as simple as making the weldment just as you do in production and then cutting and etching the welds to insure you meet the size and soundness requirements.  You may have to do one for each pipe size (or significant change in part size) but that is a whole lot easier and can be done in pretty short order.

I have a lot of experience in writing WPS's for “Unlisted” steels and take it from me, meeting D1.1 with materials that aren’t the same shape (ones a tube and ones a plate) sucks.  I would never advise it.

Sounds to me like you are the perfect example of why the AWS came up with B2.1

That's my advice and I'm only 1/2 a beer into giving it, so it should still be good.
Let me know what you decide.

PWC

It's a Work Lead... it doesn't ground anything

Hello Mr. Cameron,

I am writing this regards to an article you had wrote about grounding/grounds. I do have some

questions in regards to said article.

First of all do you have any references to the way grounds should be connected?

Secondly you mentioned in your article that grounding to a structure should not be used if at all possible. My question in regards to this: If OSHA regulations state that it is okay to ground to structures why say no to this?

The reason I am asking is that where I am employed we use the building structure for grounding purposes and we have people who are getting shocked while welding. The material is 6061, using pulse Mig and GTAW. The machines are grounded to the structure and from said structure to said welding fixture using a jumper. In a nutshell I'm trying to find references whether they be OSHA or from some other agency in regards to grounding.

Any help or information would be greatly appreciated.

Thank you,

Chris A.

Chris,

Yours is the perfect example of how the terms "ground" and "work piece lead" get used interchangeably. This leads to a dangerous situation.

On a common welding power source you will find a + stud and a - stud. To one of these you would attach a conduit leading to the electrode (ie: a wire feeder, a stinger, a Tig torch). To the other you would connect a conduit leading to a Work Lead Clamp. The polarity required would determine if the work lead runs from the + or - stud.

In the article you’re referencing I state, "…the work place lead does not ground anything." When installing welding equipment that statement is critical to remember.

OSHA will require that equipment be grounded to protect people from electric shock. The way equipment is grounded has nothing to do with the + or - stud on the front of the welding machine. This is accomplished through the permanent power connection supplying the machine (the plug). Or by a separate clamp and wire connecting the case or frame of the machine to ground (like the building). Sometimes both the plug and one of these wire connections is used. Again, they have nothing to do with the + or - stud on the machine.

ANSI Z49.1 - Safety in Welding and Cutting will require that the work table (positioner, fixture) also be grounded. This is accomplished with a conduit connected to the table or positioner, connecting it to a "driven rod" or often, the building. Again I clarify, this has nothing to with the + or - studs.

When we use the term "ground" we are talking about protection of people and equipment. You would be much better off referring to the leads coming off a welder as an electrode lead and a work lead, or a positive lead and a negative lead, but neither is ever considered a ground.

PWC

Paul W Cameron

You’re getting your “qualified” and “certified” all cobbled together…

Hi Paul,

As I was looking through the AWS website I found accredited test facilities listings. Then digging a little deeper I found AWS QC4-89 (standards for accreditation of test facilities). I was of the understanding that given the CWI endorsement, I could certify welders to the standards laid out in D1.1.

Am I to understand that as a school, accreditation is where we need to get to in order to send welders out the door with a certification? If not, what is the accreditation good for, besides marketing?
I thought that I had a pretty good handle on where I was going with this, but now I am second guessing myself.
Once again, thanks for any clarification and/or advice you can give.

Richard F.


Hey Rich,
You’re getting your “qualified” and “certified” all cobbled together…
You may have been a qualified Welding Inspector (meaning you have the skills needed) and once a 3rd party evaluated those skills you became a Certified Welding Inspector (to QC-1).
I may be a qualified Welder (meaning I have the skills needed) and once someone evaluated my skills against a standard and found that I met that standard I became a Certified Welder (to my employer or my trade union…)
The AWS runs a Certified Welder Program (Much like a Certified Inspector, Certified Educator or Certified Supervisor).  To run a program like that the AWS would need testing facilities around the country to do the testing.  The AWS wants to keep “tight wraps” on the program to maintain the programs integrity so they developed a program to certify a facility.  So there are guidelines your facility would need to meet to become an AWS Certified Test Facility.
You can still administer welder qualification tests without being an AWS Certified Test Facility, but those welders would be certified per AWS-D1.1, not AWS Certified Welders.  There is a difference.
A Welder takes a test at your facility or at his/her employer and those test results are not transferable employer to employer.  That Welders qualifications/certifications are the property/responsibility of the company.  A Welder who goes through the steps of becoming an AWS Certified Welder keeps that certification and that certification is portable.

There ya have it.
PWC