Thursday, December 22, 2016

Don't forget to Ping that Weld

Paul, Got a question for you. I work in the mines, when we are welding something thick our boss tells us to "ping" our welds (excessive chipping /with air-chipper). I've never heard of that before. What’s your input?

Matt, Your Boss is offering some good advice.  He's actually asking you to peen your weld (I'm sure he says "ping" but this is what he means).
Peening a weld helps reduce what's called "residual stress". When you heat and cool metal it wants to move, but typically the weldment doesn't allow it to move. This builds residual stress in the part.  When residual stress exceeds "Yield Strength" you'll get distortion.  When residual stress exceeds "Tensile Strength" you'll get weldment failure.
Also, welding screws with the materials grain structure (at an atomic level). There are several ways to deal with this. You can Post Weld Heat Treat the weldment: raising it to what's called the transition temperature (Around 1600f), holding it there for some predetermined time and then allowing it to cool in some controlled manner. Or you could apply vibration (vibratory stress relief), vibrating the weldment during welding and shortly thereafter. Or you can peen, hitting the weldment with a peening hammer (or a scaler) to help reduce this stress.
So, what your Boss has you doing is stress relieving each pass to reduce distortion and /or the risk of cracking.  Listen to him.
Good question.

Wednesday, September 21, 2016

Become the "Qualification Guru of Choice"

Hello Paul,

Much like yourself, I am a CWI, CWE, teaching welding classes and following the guidelines of AWS D1.1, Structural Welding Code Steel.
I have purchased a number of the pre-qualified weld procedures from the AWS bookstore that fit the specific circumstances of the most common welding practices used in our area (6010 open root, 7018 fill/cover passes).  These weld procedures are referenced in the area on the WPS for welding procedure.
Students are given a written, step by step procedure with illustrations, dimensions and weld parameters for the fit-up and welding of their test plates. Each section must be followed by the students, and signed by the Instructors. The guided bend test is performed by a qualified AWS CWI, and the test results are documented by the same Welding Inspector.
My question is: does this weld test constitute a Welding Certification?

 My answer is: It does, but will the contractors, manufacturers or company the Welder works for accept it?
AWS D1.1 tells us that Qualification (not “Certification”) is the responsibility of the “Contractor”.  They can “farm” the work of qualifying a welder out to an educational facility, but the responsibility for that Welder Qualification still falls on the contractor.  That’s the reason contractors give their own welding test regardless of any past qualifications the welding candidate may have.
Setting up a “Certification” program (meaning; backing up a Welders qualification with documentation) in a vocational school isn’t uncommon, but if that program is sold to Welders as a means of becoming “Certified”, you’ve done those Welders a disservice. They could go through your certification process not understanding that their new “Certification” is not valid anywhere.

Setting up that same “Certification” program and making your ”pitch” to area employers as the 3rd party qualification guru of choice would be far more honest and code user friendly.

I spent many years in the welding industry filling the role of Welding Engineer (The person responsible for the qualification of persons and processes), Welder qualification was a messy and time consuming part of my job.  When testing Welders “off the street” I would have a 10/1 pass rate (and then my 1 would fail the piss test).  I would always look to my area technical schools to help me with that, but I found either a welding program that didn’t give me confidence that ALL the requirements of qualification would be adhered to, or the program was nonexistent.
What do I mean by adhered to?:

•  Test plate fit-up met the WPS requirements
•  Test plate position was maintained from start to finish
•  The root pass was visually inspected (by someone who knows the acceptance criteria) and found acceptable
•  Fill passes were randomly monitored
•  The cover pass met the acceptance criteria without requiring repair to do so
•  The bend coupons were from the correct location and same test plate (I use steel stamps)
•  Removal of the backing and weld reinforcement did not fall below the plane of the base material
•  The samples were bent in the correct fixture
•  The person evaluating the bend samples understood the acceptance criteria
Seems simple enough, but at all of the locations I evaluated over my career, one or more (usually many more) of the requirements listed above were not met.
There’s a great need for the service you’re suggesting, just insure you are selling it to the right people.
Good Luck,

Tuesday, August 16, 2016

AWS-CWI's, Who needs 'em?

Good Morning,
I am very interested in a research article into industry perception of the overall value of the AWS CWI Certification. Many organizations have established training and certification programs internally that applies job scope specific training to inspectors while it seems that the AWS CWI training and exam is too general and wide ranging? Just looking for others opinions on this.
Thank you,
Victor K.

Hi Victor,
Although most codes accept the credentials of a Certified Welding Inspector (CWI) for visual inspection of welds, they DON'T REQUIRE that the Inspector be a CWI.  What they DO REQUIRE is that your Inspectors be qualified and that qualification be documented.  Those are two very important requirements; qualified & documented.  They are the requirements of welding codes that I will find not being adhered to when I'm conducting Fabricator/Manufacturer audits with in-house qualified Inspectors.

In your letter you state, "Many organizations have established training and certification programs internally that applies job scope specific training to inspectors..."  I've worked for many manufacturers and have developed those exact programs, but each program I developed insured that my Inspectors were "qualified" and that qualification was "documented". 

It is common in industry today to claim, "Our Welder is our first Inspector."  That's a great approach, but again, to make that claim, your Welders would be required to be qualified as Inspectors (don't confuse this with qualified as Welders) and their qualifications would need to be documented.

There is a document published by the American Welding Society (AWS) to help you develop that training and documentation; AWS-B5.1, "Specification for the Qualification of Welding Inspectors".  It is a terrific guide for developing a visual Welding Inspector program.  Programs developed by a knowledgeable Welding Inspector/Engineer to AWS-B5.1 would typically be excepted by your customers and/or governing agencies.  I have often found, once I've developed an "in-house" Inspector qualification, it was easier to evaluate employees and determine which inspectors may be ready to take the next step to certification.

It is typically your customers or governing agencies that put the requirement in contract documents that visual Welding Inspectors "shall" be AWS-CWI's (meaning certified to AWS-QC1-"Standard for AWS Certification of Welding Inspectors").  When listed in contract documents there's no "wiggle-room" for alternative qualification programs. 

From my own experience, walking onto a project overseen by an AWS-CWI gives me confidence that the Inspector has a good rounded background in all the different areas Inspectors need to understand.  Those areas include; Process, Code Requirements, Inspection Techniques and Metallurgy.  When I'm asked to be a 3rd party Inspector, and I find myself in a manufacturing environment where Inspectors are trained in-house, I tend to ask a series of questions that help me evaluate the qualifications of the other Inspectors.  I want to feel confident that they understand the requirements and the acceptance criteria for the weldments they inspect.  That is a bad time to find out they don’t, and I'll always ask to see their documentation.

I understand folks believing that Certification to AWS-QC1 (AWS-CWI) can, at times, be over-kill for some inspection requirements.  When an alternative program is developed you must insure that it is developed by an individual with a well-rounded understanding of welding requirements.  The kind of well-rounded understanding you'd typically find in a CWI.

Thanks for your question.

Friday, May 13, 2016

No means No

Here’s a question. I’m certified through the Iron Workers Union and I been welding for almost 19 years. Everywhere I've ever worked they says no welding downhill and if you weld downhill you won't pass the structural test.  When running a vertical weld with 7018 rod is it correct to run a downhill pass before you start your vertical ups on Structural Steel? (This email was in response to welding per AWS D1.1:2015 Structural Code – Steel)
Joshua R.

I guess the short answer is "No".
To do so, you would need a weld procedure (WPS/PQR) that qualifies welding vertical up & down with E7018.  You might struggle to find an electrode manufacturer that would support vertical down with E7018.  We’re required to use electrodes within the manufacturer’s requirements.
You (the Welder) would also need to have taken a vertical up and a vertical down Welder Qualification test with E7018 (or another Low-Hydrogen electrode).  These would be F4 electrodes.  Welding vertically down is often done with F3 electrodes, but a structural test with an F3 (E6010) will not qualify you to weld with an F4 (E7018).
I always say that the pre-qualified section of AWS-D1.1 (Clause 3 – Prequalified Weld Procedure Requirements) is filled with good engineering advice.  My “day job” consists of Ultrasonic Testing (UT) of steel structures.  Often, when I find rejects, I also find that some requirement of Clause 3 was not met. When asked, “What should we do now?” my response is always the same, “Meet the Clause 3 requirements.”  That’s not often a popular response.
Clause 3, wouldn't allow welding vertically down with E7018, so again, my best answer is still, “No”.

Good Luck,

Friday, April 8, 2016


Hey there Paul,

Had a message sent to me from a former employee, they wanted to share with me that "because I was certified by the AWS through the SENSE program my Level 2 certification (QC11) never expires." 

Was curious if you're ever heard anything like this before?

Correct, when certified through SENSE QC11 it never expires (QC10 expires after 1 year, see 9.1).  Keep in mind, this is certification to a level of education and skills training.

I received my “Degree of Occupational Proficiency – Welding” from Duluth Area Vo-Tech in 1980, it never expired.  It simply was proof that I completed the program.  An employer who understood the Minnesota Education System for “Degree(s) of Occupational Proficiency” understood the minimum requirements. So they understood what they were getting in potential employees (skill-wise anyway).  Like the vast majority of Welders I was never a “Certified” Welder, I was simply a “Welder” who was “qualified” by my company per AWS (or ASME or API…).

QC10 & QC11 were developed to create a standard for Welder Education.  Prior to the SENSE program, I could have a certificate in Welding from my local trade school, but if I moved out of my local school district, Lord knows what it meant. The SENSE program puts a clear, understandable meaning to “Entry Level” and “Advanced Welder”.

An employer is still required to administer a qualification test and maintain a continuity log.  Hiring a Welder out of a SENSE program simply helps the employer understand who they’re hiring.

Don’t get a “SENSE Certified” Welder confused with an “AWS Certified” Welder.  One is certified to a level of education, the other is certified to a Process, Position, Electrode…  The later requires the Certified Welder to maintain continuity through the AWS.

Hope that helps.

Tuesday, March 8, 2016

How Many Weld Passes?

What determines how many passes you need to make? My understanding is the weld needs to be the same profile as base metal.
Tim K.

There is a lot that goes into determining the number of passes.  First and foremost, you have to review your WPS to see what the minimum or maximum pass number requirements might be.  When the WPS does not specify then you're free to use as many or as few as your skills allow.
Here are some things that will determine number of passes:
*Travel Speed - The higher the travel speed, the lower volume of weld, the more individual passes needed.
*Weave Width or Oscillation - As with Travel, the smaller the weave the lower the volume and the higher the required number of individual beads.
*Joint Configuration - All other parameters the same, a bevel groove will need more passes then a V- groove.
*Electrode Diameter and Wire Feed Speed (WFS) - Again, all other parameters the same, larger diameter electrodes or higher WFS will increase volume per pass and decrease the overall number of passes.

A 3/8" Welder Qualification plate test completed in the 1G (flat) position might be done in as few as 2 passes, or, in as many as 7 or more.  Either can be perfectly acceptable welds made by a skilled Welder.
That same joint in the 2G (horizontal) position would probably require a minimum of 4 passes and may take as many as 9-10.  Same weld quality, just different Welder technique and comfort level.
Same joint in the 3G (vertical) would typically take a minimum of 3 passes but would be of equal quality if it took 5-6 passes.

Code books typically limit minimum and maximum pass size.  That is dependent on process, heat input requirements, material thickness and position of welding.

I've given 1000's of Welder Qualification tests and I'm almost always asked, "How many passes do I use?"  My response is always, no less then 3, and as many as it takes to insure the Groove is full, and has no more then 1/8" of Weld Reinforcement (Crown).  Other then that, you're on your own.


Wednesday, February 3, 2016

What's With Weave Width? (Woah!)

Good morning Paul,
I have a question for you.
When welding (1/8") E7018 welding rods, what's the maximum width for stringers and for weaving?  I've heard different answers but can't find anything in the D1.1 Structural Code.
Thanks and have a good day!
Ivan A.

For the process you mentioned, SMAW (E7018), you will not find many restrictions on weave/oscillation width. Table 3.6 in Clause 3 - "Prequalification of WPS's" limits the maximum size of single pass fillet welds to somewhere between 5/16" and 1/2" depending on the position.  That would be a limitation on weave width.  Table 4.6 in Clause 4 - "Qualification" would also limit weave/oscillation width in Charpy V-Notch Testing (CVN) applications by limiting heat input and weld metal volume (see: Electrical Characteristics 9).  Travel Speed plays a key role in both those calculations and weave width has a direct impact on travel speed (the wider the weave, the slower the weld progression, or travel).
With other processes (GMAW, FCAW...) weave width would be governed by the Weld Size and "Split Layer" limitations of Table 3.6, the travel speed (see: 19) limitations of Table 4.5, and the Heat Input/Volume (9) limitations of Table 4.6
Over the years as the "Weld Engineer" on specific projects I've come up with weave width limitations that I have found to work in my applications.  They were not limitations listed on a Weld Procedure Specification (WPS) because of a code requirement, they were listed on the WPS because of the "Engineers" requirement (mine).
I'm sure you came looking for a "hard" number you could use to determine weave or oscillation width.  But that is a number that you would need to calculate given your specific requirements.