Welder Perfomance Question Pertaining to Fillers

Date 09-18-2012 02:42

Following your logic the welder that qualifies on aluminum is also qualified to weld titanium per D1.1. Does it sound reasonable?

Al

By Lawrence (*****)

Date 09-18-2012 03:47

Al

Does it sound reasonable that welders who have qualified for FCAW-S are also qualifed for FCAW-G ?

Again Al, Where does D1.1 direct further welder performance qualification if a PQR has been completed and a WPS has been generated, with the given (which the OP supplied) that welders are already qualified in process?

Are you suggesting that every time a steel or filler is used that is not on the prequailfied list, that production welders must do fresh performance qualifications in addition to the PQR?

You aren't getting away with a one liner here pal :)

By tom cooper (**)

Date 09-18-2012 11:40

this must be a trick question Al....ok, I'll bite - the answer is no because aluminum or titanium wouldn't be covered by D1.1; on the other hand, AWS D1.1 clause 4.2.2.1 allows an Engineer to accept a performance qualification by another standard. But to answer your question in the scenario you describe - in my opinion it is not reasonable but to some Engineer it may be acceptable.

Reasonable or unreasonable, it is perplexing to me that Table 4.12 distinguishes performance essential variables based on SMAW electrode strength but does not distinguish analogous differences for GMAW electrode strength or GTAW filler strength.

So Mr SCWI (and I say that with fervent respect), in your opinion is my welder good to go by the curent D1.1 verbiage or not?

By jwright650 (*****)

Date 09-18-2012 12:16

>I have two separate qualified procedures for D1.1 applications using both GTAW and GMAW on an unlisted material (AISI 4130). The filler >used is 90S-B3 for both processes.

>We have a production welder who in the past was tested (and qualified) using 70S wire on common AWS listed steels using both GTAW and >GMAW processes.
>Is this welder qualified to weld the 4130 production welds using 90S wire, or must he be tested ?

I think the welder is good to go. He's already qualified on both processes(GMAW and GTAW). Nothing in Table 4.12 says that this individual needs to requalify IMHO. He has satisfied Table 4.12(1) and nothing else in the Table seems to apply to the situation.

What is the difference when a welder qualified using E7018(F4 electrode) and then welds with E11018(F4 electrode) in production? Seems to only be a filler strength change which isn't an essential variable requiring requalification according to Table 4.12. Item (2) refers to an electrode difficulty rating not a strength difference....ie F1 vs F4 electrodes, where F1 is a very easy to use electrode vs the F4

I think the performance of the welder isn't going to change just by switching filler material in your case. If the welder passed the qualification testing for each process, then what more could you do?

By tom cooper (**)

Date 09-18-2012 12:50

Thanks JW,
that makes a lot of sense and also for clarifying the Table 4.13 electrode classification groups are separated by degree of difficulty, not by strength.
Please have a very nice day.

By 803056

Date 09-18-2012 16:06 Edited 09-18-2012 18:23

As I thought, my off-the-cuff response got the brains smoking. It is good to stir up the mud on occasion.

The 4130 is not a prequalified base metal, but the contractor did qualify the WPSs, so there is nothing inconsistent with D1.1 (2010) regarding the use of the WPSs for production. That is assuming the WPSs were qualified properly, i.e., the bend tests were done using the correct bend radius, etc. I would like to know what the contractor used for the minimum tensile strength since AISI does not include requirements for the mechanicals. Was the AISI supplied as hot rolled, cold rolled, or normalized? The mechanicals can vary considerably depending on the condition of the supplied raw material. The bottom line is whether the WPSs were in fact qualified in accordance with AWS D1.1. Based on the information provided, I would hesitate to say yes.

As for the welder performance qualification testing; the tests prescribed by D1.1 are intended to demonstrate the welder's ability to deposit sound weld. Again, I would want to review the test records to see if the welders were in fact qualified per AWS D1.1. Did they follow a prequalified or qualified WPS when they welded the test coupon? Did the contractor allow the welders to back gouge the root to sound metal before welding the second side? I ask because it appears a number of forum participants routinely permit the welder to do so. My position would be that the welders were not qualified to D1.1 if that was the procedure used. I am making assumptions that are not part of the post, but I do so because we are being asked to render a decision on incomplete information. I tend to take a very conservation position when incomplete information is provided. There are simply too many unknowns involved to draw a meaningful conclusion.

Let us assume the WPSs are in fact properly qualified and let us assume the welders were properly qualified. It is a stretch, but I will go along with the game. Table 4.12 lists the essential variables that pertain to welder performance qualification. Many have noted that neither the base metal nor the strength of the filler metal is considered to be an essential variable with regards to performance qualification. The F number does not come into play when SMAW is not the welding process, so it is not a factor in this case. We are assuming position, diameter, thickness, and uphill or downhill progression plays no part in the inquiry.

The CWI is not in the position to accept or reject the welder performance test records if he/she is acting in the capacity of the Verification Inspector. The Engineer is the individual that has the responsibility to determine if the welding documentation submitted by the contractor is adequate for the needs of the project. While the CWI or the SCWI may be asked for an opinion, he/she can only offer an opinion; he/she cannot make the final determination. On the other hand, the Contractor's Inspector is given the responsibility to determine whether or not the prequalified WPSs and those WPSs qualified by testing meet all the requirements of D1.1 as per clause 6.3. Previous performance qualification may be approved by the Engineer per clause 4.2.2.1. If the Engineer deems previous qualification acceptable, the Verification Inspector is left with little alternative other than to let the welding proceed.

My position is that there is little difference, if any, in the skills required to weld low carbon steel or high strength low alloy steel. A welder that is qualified to weld any of the steels listed in D1.1 should be able to deposit a sound weld on any carbon or low alloy steel provided he has a viable WPS to follow and if the WPS is followed. The latter is the chink in the process, not all carbon and low alloy steels behave nicely when welded. AISI 4130 is just one of the many low alloy steels that can be a bad actor if the welder does not follow a properly developed WPS. While D1.1 defines the minimum requirements that must be met, it is incumbent upon the contractor to take any necessary steps required to ensure the completed weldment will perform as intended. If it is prudent for the contractor to require the welder to demonstrate the ability to follow the WPS it is his responsibility to do so. The commentary C-4.19 makes the case that the contractor should provide instruction to the welder regarding the properties of quenched and tempered steels (AISI 4130 can fall into this category depending on its condition when welded).

A review of code interpretations can also offer some useful insight regarding how the code committee might perceive different situations.
Inquiry: (1) A Group V to Group V metal of Table 4.1 weld qualification is made. Is the procedure and/or the welder qualified to weld a Group V metal to any other Group V metal listed in Table 4.1?
(2) A Group V steel to a nonlisted metal weld qualification is made. Is the procedure and/or welder qualified to weld the nonlisted metal to any other Group metal listed in Table 4.1?
Response: (1) No. Subsection 5.5.1.3 covers welding Group V to Group V base metals. However, the procedure applies only to welds made [using] the specific ASTM material specification and minimum specified yield strength as the base metal [for running] the procedure, without regard for Group number. Se the example cited in 5.5.1.3. However, the welder is qualified to weld all steels in Table 4.1 by virtue of the fact that the material grouping of the steel is not a welder variable.
(2) No. Steels that are not listed in Table 4.1 require procedure qualification and the procedure only qualifies on the combination of materials tested (see 1.2.2). The welder in this situation again is qualified to weld on any Table 4.1 material by virtue of the answer given to Inquiry (1) above.

I believe the inquiry cited provides a reasonable basis of permitting the welder to weld the nonlisted steel assuming the WPS was properly qualified and there are published mechanical properties for the unlisted low alloy steel. That is the fly in the ointment unless the base metal was ordered to an ASTM or other specification (ASM) that includes the state of heat treatment and the minimum mechanical properties the WPS probably will not stand.

Best regards – Al