About WPS for Steel CVN required(AWS-D1.1/D1.1M:2006)

By swnorris (****)

Date 01-25-2008 14:17

Item 6 eliminates the need for CVN testing in all positions, but does not change the requirements of Table 4.5 regarding welding positions. Note that the word "test" is underlined at Item 6.

By hung7601 (*)

Date 01-25-2008 15:37

With WPS/PQR required CVN test, I applied only 1 PQR at 3G up and support WPS qualify for all position, this also accepted by client and 3rd party as well

By pax23

Date 01-25-2008 19:32

swnorris is right on.

The standard tests to qualify a WPS are visual, NDT (RT or UT), bends, and tensiles. This is for CJP groove plate, for clarity I will not address other scenarios.

Visual is evaluating workmanship, NDT is evaluating weld soundness, bends are evaluating ductility, and tensiles are evaluating strength. The code requires you to qualify the WPS for each position that it will be used. So the code feels that the welding position could affect one or more of these characteristics/properties (workmanship, weld soundness, ductility, or strength).

Occasionally, you need to also evaluate toughness. We do this through CVN tests. However, the code has stated that a 3G vertical up qualifies for all. This is because the heat input is significantly greatest in vertical up than in any other situation. Since heat input is the overriding factor in toughness, the accepts 3G up for all.

The same is not true for workmanship, soundness, ductility, and strength, so each position needs to be qualified separately.

For a simply plate groove CJP, I would need to run 2G, 3G, and 4G (per table 4.1) to qualify, ie. prove acceptable workmanship, soundness, ductility, and strength results for all positions. But I would only need to pull CVNs out of the 3G (up) plate in order to prove acceptable toughness results for all positions.

By Kix

Date 01-25-2008 20:44

Where does it say 3g vertical qualifies for all?

By pax23

Date 01-25-2008 20:51

It qualifies for all positions for CVN tests. This does not replace the requirements stated in Tables 4.1, 4.2, and 4.5. Table 4.6 merely supplements those base requirements, which is another way to say it adds to them.

By Kix

Date 01-25-2008 20:54

How do you know when you neec to do cvn testing? I did a 6g procedure to get me across the board, but now do I need to do a 3g for cvn to show toughness results?

By pax23

Date 01-25-2008 21:12 Edited 01-25-2008 22:01

You need to do CVN testing when the contract, client, or project require it. The code does not mandate any CVN testing; it simply gives the procedure and acceptance criteria if CVN testing is required.

Good question about the 6G test. That question is relevant for a 5G test as well. Figures 4.7 and 4.8 show you where to pull CVN specimens from tubular members. Seems as if the pipe has a large enough diameter where you can pull the required specimens from the circumference of the pipe that is defined as being in the vertical welding position (the sides, see Figure 4.1 or better yet, A3.0:2001 Figure 16C for better definition) you should be able to use those specimens to qualify for all positions. But that's not what the code says. It specifically says a 3G test. I have a feeling that was an oversight.

People interchange welding positions (F, H, V, OH) and weld test positions (1G, 2G, 3G, etc.) as if they are equivalent terms. They are not. They each have a specific meaning. I've seen this error made in publications before, even AWS codes.

[Brain hiccup - the code is fine, 3G is an example to clarify text before it. See better response below]

By esam

Date 06-23-2008 20:49

would like to ask if the material to be joined by welding is CVN tested ( un assigned s355j2), is it a code requirement to perform CVN test on the WELD DEPOST (PQR) according to aws d1.1

By pax23

Date 06-23-2008 21:17

It would make sense that if the contract documents required CVN testing (or certification of toughness properties) on base material then the welding procedure would also need to be CVN tested. However, it is the Engineer's responsibility to specify CVN weld tests in the contract specs, see 2.2.2 in the D1.1 code.

By esam

Date 06-24-2008 07:44

that means clearly that in our case it is not a code requirement but it shall be stated clearly in the project specification

By esam

Date 06-25-2008 09:11

according to para. 2.2.2 , please correct if i am wrong , we have two alternative 1) the filler metal is CVN tested by filler manufacturer , or 2)we will qualify a procedure with addition to CVN on test coupon , if we used the first alternative does that means that table 4.6 applies knowing that the cvn test results in the filler metal certificate matches with the designer acceptance criteria of minimum absorped energy required , please reply

By pax23

Date 06-26-2008 14:12

Yes, the Engineer can either specify that (1) only filler metal meeting a specific CVN value be used but waive the need for CVN testing, or (2) require CVN testing.

I do not see the logic in applying Table 4.6 to the WPS if you did not perform CVN tests in the first place.

The specified CVN minimum values on filler metals are verified by manufacturer's tests in the flat position in very controlled testing. Heat input is the greatest contributor to notch toughness degradation. The welding parameters used in production welding have a great effect on heat input. Production welding parameters could greatly increase the heat input above and beyond what was done in the manufacturer's tests so just because the manufacturer's tests achieved the specified CVN minimum values does not ensure that all production welding using those filler metals will also achieve those values. CVN testing on the specific welding procedure is that extra control to ensure notch toughness in the weld.

In the end, it is up to the Engineer to determine to what degree he wants to ensure the welded joints achieve certain notch toughness values. In most structural applications notch toughness is not a concern. In others it may be a borderline concern but one that does not mandate additional testing. While in others it is of great concern. Ultimately it is for the Engineer to decide. Often, in the later instance there will be other design or fabrication codes that mandate the Engineer ensure notch toughness in the connections.

See also the commentary C-2.2.2 in the D1.1 code.

By esam

Date 11-30-2008 16:33

thanks pax ,
would like to know what is meant by auxiliary attachment mentioned in para.(3.4) in chapter 3 ( prequalification) , how can u identify the attachement if it is auxiliary or not, by comparing dimension or weight with the main member ?

By pax23

Date 12-01-2008 14:55

There is a definition in the annex (Glossary) of D1.1.

auxiliary attachments. Members or appurtenances attached to main stress-carrying members by welding. Such members may or may not carry loads.

I understand this definition as anything other than a main stress-carrying member is an auxiliary attachment.

Identification is another matter. Even those with a limited understanding of how structures transfer stress through its members can spot the obvious members that would fall into this category. Other situations may be harder without some more advance understanding and some practice in structural design. While in complex structures, for some members, only the designer would really know for certain.

A good understanding of statics and mechanics of materials will lay a foundation for the identifying the obvious, but guessing beyond your own limitations will often get you in trouble. If you don't know for certain, ask.

By esam

Date 12-14-2008 17:11

hi , i wonder if the checked box of globular in the informative annex e /aws d1.1 2004 of sample wps form is right ?, the process is FCAW !

By pax23

Date 01-25-2008 21:48

Table 4.6, EV6: reads, "A change in position to vertical up. A 3G vertical up test qualifies for all positions and vertical down."

If I take all my CVN specimens from the vertical portion of a 5G or 6G test (where I welded up) then I have tested and qualified specimens for vertical up. EV6 says a change in position to vertical up. So the initial start point is qualified to vertical up so I can never change to vertical up. I'm qualified for all positions.

So, 1G qualifies for flat, horizontal, vertical down, and overhead
and 2G qualifies for flat, horizontal, vertical down, and overhead
and 3G down qualifies for flat, horizontal, vertical down, and overhead
and 3G up qualifies for flat, horizontal, vertical down, vertical up, and overhead
and 4G qualifies for flat, horizontal, vertical down, and overhead

- this is only CVN toughness test here, this again does not replace the need to do the base tests specified in Table 4.2.

Thanks for the good question. It got me thinking. That's hard to do late on a Friday.

By Kix

Date 01-27-2008 00:26

Very good explanation! This should help for many to look back on and give them some good insight. Thanks for clearing that up for me.

By ctacker (****)

Date 06-28-2008 03:14 Edited 06-28-2008 04:14

alot of good info so far, I just got a bombshell from cityof new york transit, we are starting a job for them and I sent a prequalified WPS for A588 using E70C-6M H4. I was then informed that CVN req's 15 ft-lbs (20 joules) in the CGHAZ (coarse grain haz) 1mm from fusion area @ -20F.

the wire I submitted has CVN values of -20F 59 ft-lbs(79 joules)
My boss had this info on his shelf and not in the data pkg, so I was surprised by the need for CVN.
being new at this I dont know which way to go and he wants to start work next week. my question is how do I get the values (79 joules down to 20) and still use the same wire, or must I find another wire that will get me where I need to be?

edit: what do the joules mean? I'm used to values in the thousands?
please excuse my lack of knowledge on this subject, This is a first for me having to deal with CVN values. its something I need to get right the first time!

By pipewelder_1999 (****)

Date 06-28-2008 16:16 Edited 06-30-2008 14:33

Joules is just a measure of energy. It can be watts, impact energy etc.

59 FT/Lbs at -20 is a better impact value than 14 Ft-Lbs at -20. But that is only your wire.(Weld Metal)

The statement I made below is incorrect. My head was in the wrong place.

You should be able to take your procedure, run a test and just do impacts.

This is still true

Regardless of the wire, the procedure can affect impact values, heat input, preheat, interpass etc can all affect the impact strength in the HAZ.

By ctacker (****)

Date 06-29-2008 03:10

the job also calls for PWHT, so can I take my Prequalified WPS run a sample, have it PWHT and take the CVN samples from it without doing the tensiles and bends?
Also, do I need to run a single pass groove and multipass groove to satisfy the code (table 4.6 item 12) when I will be running single and multipass fillets in production?

One more thing, if i qualify with a robot, is the pqr good for semi-auto welding also, or Vice-versa?

Thanks
Carl

By pipewelder_1999 (****)

Date 06-30-2008 14:25 Edited 06-30-2008 14:35

You will have to qualify the procedure both for the CVN and the PWHT.

EDITED: Previous Statements I made were incorrect.

By Noel Tan (**)

Date 01-29-2008 09:31

viettq,

Quote: I understand that: If a WPS is qualified 3G vertical up only, it will be qualified all positions.(for WPSs required CVN Testing only)
this is correct if the applicable code is ASME IX and this is wrong if the applicable code is AWS D1.1

Best Regards,
Noel Tan