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Up Topic American Welding Society Services / Technical Standards & Publications / Item 34-AWS D1.1 2008 Table 4.5
- - By N.D.Phuong Date 10-19-2011 09:08
Hello brothers,
I am from South East Asia and I am working as QC inspector in a Shipyard.
I come our forum with a question as topic subject.
May you clearly explain this statement "The omission, but not inclusion, of backing or backgouing" ?
-> If our WPS qualified using ceramic backing welded one side, now can we weld both side with backgouing? (We don't intend to use Prequalified WPS)
I have already studied in BV, DNV, Lloyd's Register Rule, this issue is stated clearly and easy to understand.
The followings are stated in LR.
-WPS/PQR (butt joint)                           Qualification Range
One side with backing                           one side with backing, both sides with/without gouging
             without backing                       all
Both sides with gouging                         both sides with gouging
                without gouging                    both sides with/without gouging
Thanks in advance,
Phuong.
Parent - - By Joey (***) Date 10-19-2011 09:51
I guess you're from Vietnam, I believe the answer to your question is YES.

~Joey~
Parent - By Shane Feder (****) Date 10-19-2011 12:49
The answer is Yes
Parent - - By bhichai.s (*) Date 10-19-2011 15:15
Yes, you're right.

:grin::grin::grin:
Parent - - By eekpod (****) Date 10-19-2011 18:08
What does BV, and DNV stand for ?
Parent - By Superflux (****) Date 10-20-2011 13:45
I've done stuff for these 2 entities.
BV= Bureau Veritas
DNV= Det Norske Veritas (Norwegian North Sea platforms) they are like American Bureau of Shipping and Lloyd's Register.
Parent - - By N.D.Phuong Date 10-20-2011 01:18
Brothers, why do you know exactly where I am from? :grin:
So, may you explain me the question in D1.1?
I am looking forward to your answer.
Phuong,
Parent - By Joey (***) Date 10-20-2011 01:47
"The omission, but not inclusion, of backing or backgouing" ?

The key words are "omission" & "inclusion" ; the meaning of these words can be found in English Dictionary?
backing or backgouging - this should not be a problem for you if you are a welding inspector.

I often travel to Vietnam, Phuong is common there:lol: same as the surname "Kim" in Korea

~Joey~
Parent - - By 99205 (***) Date 10-20-2011 04:55
Hmm, maybe your name is clue.  I would like to visit Viet Nam again.
Parent - - By N.D.Phuong Date 10-20-2011 06:16
Thanks for your answer.
But I am still not satisfied, the meaning of each word is clear, but that statement make me confused.
Even ABS foreigner surveyor couldn't give me a answer.
Once, if our WPS qualified by welding one side with ceramic backing, can this WPS cover for welding both sides with backgouging and vice versa?
Warmly welcome to Vietnam.
Parent - - By eekpod (****) Date 10-20-2011 10:54
ND Phoung

What code are you referring to specifically so we know what to referance?

You mentioned what I believe are shipping/marine codes in your original post.  Or are you asking in referance to D1.1 which is for buildings? there's a big difference, building don't float.
Parent - - By Shane Feder (****) Date 10-21-2011 00:09
Mr Phuong,
Greetings from Thailand.
1 If you weld with ceramic backing you have non metallic "backing"
2 If you weld with plate backing you have metallic "backing"
3 If you backgouge and reweld you have weld metal "backing"

4 If you weld from one side only with no metallic or non metallic backing you have what is classed as "no backing".
Inclusion is to add and omission is to remove/delete.

If your WPS is qualified single side only you have no backing so you can "add" non metallic backing, you can "add" metallic backing or you can backgouge and reweld so you have "added" weld metal backing.

Omission is not allowed so you cannot remove the backing.

Easiest way to explain is if your WPS was qualified on 1, 2, or 3 your WPS is good for 1, 2 or 3
If your WPS was qualified on 4 your WPS is good for 1, 2, 3 or 4

Regards,
Shane
Parent - By N.D.Phuong Date 10-21-2011 03:38
Many thanks brothers, and Mr. Shane.
Phuong,
Parent - - By bhichai.s (*) Date 10-21-2011 05:50
Shane,

Very good job, your explained is very easy understood.

Thank you very much.

PS. May I pay Sang Som, Hong Thong, LEO or Singha for you in the few time.

Kob Khun Krab.
Parent - - By nantong (**) Date 10-21-2011 11:13
What if you are welding say a single "V" butt with a ceramic tile. Material is higher strength material and procedure requires hardness testing and it passes.

Can you allow backgrinding/backgouging for production welds with a single pass to fix the root for example if it is not completely fused in areas? Does AWS D1.1 require welding from both sides if both sides are accessible?

Grasshopper, how are you back in Thailand already? I thought you were only leaving China today?
Parent - By Shane Feder (****) Date 10-22-2011 01:03
Hey Mr B,
Sitting having a Singha for breakfast while I am typing this.
Enjoy your break and say hello to E for me,
Cheers,
Shane
Parent - - By Richard Cook (**) Date 10-27-2011 19:22
Yes, AWS D1.1 recognizes that backgouge to sound metal and welding from the second side as a "weld with backing". Backing as defined by AWS can be flux, ceramic, copper, base metal and or weld metal. So as you discribed 34 is not an issue, you have backing.
Parent - - By Lawrence (*****) Date 10-28-2011 04:34
Richard

Not to be too knit-picky but,  I think you are describing a Backweld rather than a Backing weld.

A Backing weld must be put on first or it isn't backing eh?.
Parent - - By Richard Cook (**) Date 10-28-2011 12:27
The bottom line is the first weld is the backing for the second weld, no matter what you may call it, complying with the intent of the code. To many people over think the issues, play on words and ignore what is practical and compliant. A back weld can be a backing weld.
Parent - - By Lawrence (*****) Date 10-28-2011 13:49
Maybe I am overthinking it.

But in your first post you said: 
"AWS D1.1 recognizes that backgouge to sound metal and welding from the second side as a "weld with backing". "

I really thought there was a difference... Since with a "backing weld" you simply cannot gouge to sound metal, since it is the first weld of the joint.

Not trying to play on words either, I was just asking a question and offering some reasoning behind it.

If you fill weld a joint entirely, and then flip it over, gouge to sound metal and place a :backweld"... Does the D1.1 code consider that a weld with backing?    I really diddn't think so.

My understanding was that if a weld was to be a "backing weld"   it had to be placed first or it wouldn't serve as "backing" as defined by the code.

AWS A3.0 (fig 24 D) makes it pretty clear that a backing weld shall be made on the *other side* prior to the groove weld being placed.

I agree that weld metal can serve as backing... But can you explain via the code, how a weld can be considered to be backing if it's not placed first?
Parent - - By Richard Cook (**) Date 10-28-2011 16:03
I simply answered the initial inquiry as to the issue he explained.
My statement is correct, just think it through, the first side that is welded becomes the backing for the second side that is welded. So you always have backing. With a back weld, the first side is welded with the base metal as the backing, then backgouged to sound metal and welded from the second. So, essentially the first side welded becomes the "backing weld". You cannot "back weld" without backing, because it exists in the natural course of things.

We use "backing welds" all day and backgouge to sound metal before completing the groove weld, its good practice, and ensures a proper fusion to the backing weld, since the root side of the "backing weld" is not consistent due to many variables and factors, you may consider it as joint prep.

Now here's a question. If you place a "backing weld" does that now become a weld without backing from one side? If you do not backgouge, yes?! Remember D1.1 states welds made from one side with out backing is prohibited without qualification, so do you qualify a procedure to make "backing welds", no you backgouge.

I do not disagree with your understanding of back weld verses backing weld, but it is all semantics for the issue at hand.
Parent - - By 99205 (***) Date 10-28-2011 16:10
AWS A3.0(2010), Fig. B24c - Back weld,  Fig. B24d - Backing weld.  Reviewing those two figures should clears things up.
Parent - - By Richard Cook (**) Date 10-28-2011 16:28
Have no issue with understanding the figures, and agree, but it had no bearing on the original issue at hand. Each came into play with the issue at under discussion. Yes, when you remove the ceramic backing, you "back weld", but now the weld on the other side now becomes a "backing weld", right??
Parent - - By 99205 (***) Date 10-28-2011 19:44
I've use ceramic backing in the past and understand what your're getting at.  With the proper profile on the ceramic backing your first pass produces a "backing weld".   Everything after that would be, root, fill and cap.  I try to keep things as simple as possible.
Parent - By Richard Cook (**) Date 10-28-2011 20:13
Yea that is another whole issue though (non-fusible vs steel backing) with AWS. Being that the WPS is qualified with ceramic, that issue goes away.

I go back to the original question, can a WPS, qualified with ceramic backing, be used for welding with backgouge and weld from second side. AWS D1.1 does say, that any "qualified" WPS may be used for any prequlaified joint detail also (table 4.5, 31). I reference AWS because I understand the question to be based on this standard. My answer is still yes to his question, if a prequlaified joint detail is used.
Parent - By Lawrence (*****) Date 10-28-2011 21:30
Richard,

I think your right.

I've been reading this thread off and on for a few days and posted my first question to you without reviewing the whole thing again to get my berings.

Sorry about that.
Up Topic American Welding Society Services / Technical Standards & Publications / Item 34-AWS D1.1 2008 Table 4.5

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