Prequalified Base Metals

Date 02-01-2020 18:55

Multiple listings on the CMTR simply means the material meets the requirements of multiple base metal specifications. The base metal can be used when the bill of materials/drawings specify any one of the ASTM base metal specifications listed by the CMTR.

This is not uncommon. Even if you called your vendor and requested a sheet of A529, the CMTR would more than likely list ASTM A529 as well as several other ASTM material specifications. There is considerable overlap when it comes to the material specifications with regards to chemistry and properties.

From my vantage point, I would like to see the material specification listed by the PQR as well as the WPS. The CMTR should be included with the PQR as a supporting document (just like the laboratory test reports). Yes, the CMTR lists several ASTM base metal specifications, so pick one for the PQR. It would be a smart move to list one that is included as a prequalified base metal so that all of the prequalified base metals in that group are included. If you pick one that isn't prequalified (that's why you are qualifying the WPS), the WPS is only qualified for the base metal listed by the PQR per clause 4. In the case of the latter, I would list both a prequalified base metal and the unlisted base metal (assuming both are listed by the CMTR). If that is the case (both a prequalified and unlisted base metal specification are listed by the CMTR), the WPS will be qualified for any of the prequalified base metals in the applicable group as well as the unlisted base metal.

So, back to your question, on the PQR include the following information:
- List the ASTM Specification and the grade/class, etc. that is the base metal you need to qualify,
- list the alloy family, and
- list the AWS group

Don't forget to include the thickness (and diameter if applicable) and manufacturer and heat number/slab number listed by the CMTR. The more information included by the PQR, the easier it is for someone to review the documentation and follow the thread back to the supporting documentation.

There is a seminar on developing WPSs and PQRs coming up in March 2020. You might be interested in attending. Contact: amoore999@comcast.net. The seminar has received good reviews from everyone that has attended. Generally, the seminars sell out and walk-in are not accepted.

Best regards - Al

By welderbrent (*****)

Date 02-01-2020 22:44

Al,

Did I miss something? Why are we talking about a PQR when using a Group II steel for D1.1 testing?

Note, info I see also eliminates 'Certified MTR's' for many normal operations. Some jobs may still require them but according to AISC and papers on specifying your steels when ordering state that MTR's (non-certified) meet all requirements for the construction of buildings. Other sectors may still require certified test reports. Certified will often cost more because of the above normal documentation and testing that may apply.

OP,

I concur with Al on material grades. I am seeing many of our structural jobs specifying A572-50 instead of A36 for flat bar, plate, and angle iron. But, when the material comes in, especially from USA mills, it is normally multi-grade and lists A572, A709, A36, A529 and/or other designations that may apply.

The overlapping is getting less variation as A36 is weeded out of stocks of steel. Bridge code, structural steel, are all wanting tighter controls over tensile, yield, and other properties than what A36 specs were providing making some engineering very difficult. Just like the change and it is almost impossible to now find A36 W-shapes. They first went to A572-50 and are getting everything now to the final goal of A992 for W-shapes because of the mechanical property values.

And I would submit that stating 'Group II' steels would suffice for your application to produce a WPS for the materials in use.

Have a Great Day, Brent

By 803056

Date 02-01-2020 23:09 Edited 02-01-2020 23:13

"I'm writing a WPS for a 2G test. I'm trying to decide if I want to use the plate steel that we get from our local mill, or if I need to buy specific steel just for the tests."

The inference I get from the sentence is there is a test being performed. I take that as meaning there is a reason it doesn't comply with prequalification, thus a test is required, i.e., a PQR."

I didn't see anything in the post that stated this is for a building, a bridge, etc. It could be that the project involves a piece of equipment that is being built using D1.1 as the governing code. I inspect railcars on a regular basis that are welded using D1.1 as the governing document.

Another example of limited input = limited output.

Al

By welderbrent (*****)

Date 02-02-2020 00:45

Got it Al. I understand your reasoning and the limited input issue.

By jwright650 (*****)

Date 02-02-2020 00:01 Edited 02-02-2020 00:32

Is the steel you are asking about writing a WPS for qualifying your welders in a 2G position?

In another post, the OP was working towards qualifying the welders for a joist fab shop.

By 803056

Date 02-02-2020 14:58

They qualify welders for open web joists?

I don't believe they test to AWS standards. If I remember correctly, they have their own fabrication standards that addresses the testing of welders. About the only defect addressed was cracked welds on product.

I had a major run in with a major joist manufacturer many years ago. Their sales literature said their joist girders were designed and fabricated to AISC. The welds were so bad, how bad were they you ask? They were bad enough that it took them about 8 months to repair all the welds in the field. They insisted they were welded in accordance with SJI standards. I took the position that AISC requires the welds to meet AWS requirements.

We excavated a good number of welds only to confirm my suspicions that the welds were not fused to the chord members. I include a number of photographs of the welds in my training programs.

My very next job involved joist girders from the same manufacturer. They refused to deliver the joist girders to Connecticut unless the Owner and general contractor agreed that I would not be allowed to inspect them. I can only hope the quality improved before they were delivered.

Al

By welderbrent (*****)

Date 02-02-2020 15:12 Edited 02-02-2020 15:18

LOL...

Contractors/fabricators/erectors should have zero say in who is to perform Special Inspections or Verification Inspections.

Too often we know they get chosen because they don't find nearly as many indications in UT as other techs do. The other techs have been proven to be accurate but when they show up on a job, many more rejects are discovered than the shop is used to dealing with. After some observation it is obvious that calibration is not performed properly, D1.1 Clause 6, soon to be 8, procedures are not followed properly, and other simple things like inches traveled in performance of UT (I call them lightening arms).

Of course a contractor is going to request QA by those they know won't slow down production by finding the rejectable indications. The less they repair, the more they increase profits instead of just doing it right in the first place.

Joists are looked at where connection is made and for overall compliance. Meaning, there are times they are damaged beyond acceptable tolerances in shipping and/or handling. Overall, they are a code and procedure unto themselves.

I do find this thread interesting in that, while the material is multi-grade, they are specifying the material to bridge code materials while doing qualifications of some sort to D1.1. Why are not the materials specified to A572-50 or A36? Yes, the A529 is in D1.1 Clause 3, soon to be 5, but normal usage not the same. A529 is not a normal spec for structural steel materials in buildings.

Have a Great Day, Brent

By jwright650 (*****)

Date 02-02-2020 15:39

https://app.aws.org/forum/topic_show.pl?tid=39248

Al, This is the thread.

By snutt Date 02-03-2020 10:39

Sorry for the confusion. Yes, this is to prequalify a 2G test to qualify our welders. I just wasn't sure if a multigrade steel was prequalified or not.

Our industry does weld to SJI standards, which from my understanding is just a more relaxed approach to D1.1. Since we run webbing with metals less than 1/8" thick, SJI allows D1.1 and D1.3 to be combined to account for it. However, SJI does say that welders need to be qualified to AWS or CWB standards. We have 7 divisions across the USA and we all qualify our welders to D1.1. I definitely hope the quality improved with those joists and girders as well!!!

By 803056

Date 02-03-2020 14:53

Hello Snutt;

Thanks for the clarification.

You can qualify the welders using any of the prequalified steels listed in D1.1. A steel that has several ASTM, ASME, or other organizations listed are acceptable and can be used provided at least one of the base metal specifications listed includes one listed by D1.1 as prequalified.

It is pretty common to see several material specifications listed by the CMTR provided by the manufacturer. It simply means that the mechanical properties and chemistry fall within the ranges permitted by each of the material specifications listed.

Do yourself a favor, when listing the base metal, only list one. Don't list more than one because it looks to the person reviewing the paperwork like you are not controlling the materials used for testing. For instance; listing "A36 or A572 grade 50" makes it appear the test plates could have been either A36 or A572 grade 50. Which was it? The material could have been dual certified, but the individual reviewing the welder qualification test record has no way of knowing. What if the test report listed AISI 1025 or A36? The AISI material isn't a prequalified base metal, but A36 is. I would reject any welder qualification record that stated AISI 1025 was used. So, did the welder use AISI 1025 or by chance did the welder happen to use A36? Eliminate the confusion by simply listing the one base metal specification that is prequalified. Simplify your life when possible.

Back to the joist girders, the main problem was some of the welders were in short circuiting transfer mode. The overlap was unbelievable. We excavated hundreds of welds and it was obvious there was no fusion to the chord members. Those fillet welds failed to fuse through the mill scale. You could easily see which welds were made using spray transfer, no problems. There were a number of welds with crater cracks and a few longitudinal face cracks, but most of the defects were due to overlap.

Al

By Vansledge (*)

Date 04-09-2020 21:01

Hello Al,
Am sorry to bring this up, cos its almost an old thread.
But my cofussion is this
Assuming am qualifying a WPS and the material am going to use is found in Prequalified section alone (e.g 106 grade B) please can the material be use for PQR other than Prequalified WPS.
Thanks once again

By 803056

Date 04-09-2020 21:14

Yes. Let's assume that there is an engineering requirement that the welded joint meet toughness requirements, i.e., CVN. In that case the WPS is not prequalified, thus it would have to be qualified by testing in accordance with the clause that covers tubulars. The specific clause is dependent on the code edition referenced by the building code or project specifications.

The same holds true if the tubular is welded from one side without the benefit of backing or back gouging. The WPS is not prequalified, thus the WPS would have to be qualified by testing.

What if the groove angle is less than that specified by a prequalified joint details? The WPS would have to be qualified by testing.

In each of the examples given, the contractor could be required to qualify the WPS by testing using a prequalified base metal as per the approved drawings or project specification.

Al