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Up Topic Welding Industry / ASME Codes / bead width concern
- - By Jovi Zhu (**) Date 11-01-2020 14:14 Edited 11-01-2020 15:09
I remember relevant topics had been disscussed somewhere on this forum.

Guess I'm not the only one encountered a 3rd party or customer inspector rejecting a weld due to its as-welded "weld face" width.
I do see some Code paragraphs limiting the width of bead to a certain level such as 4x the electrode core diameter. And some welding recommendation imply that purpose of it is to control the heat input...

In my earlier career working with many seasoned welding people I don't remember any concern raised for the bead or weld face width.

Please note that I'm using the term "weld face" width from AWS A3.0 other than "bead width" so here is my question:

Can the width of "weld face" in the as-welded condition be considered as "bead width", especially when weave bead technique is used?

Happy to know and learn from any ideas or thoughts.

Cheers,

JZ
Parent - - By 803056 (*****) Date 11-01-2020 21:27
Show me where in the code the width of a bead is limited. Don't tell me it is in there somewhere, show me where, chapter and verse.

Layer width is not the same as bead width in many cases. A layer can consist of several beads deposited side by side or the layer can consist of a single weave bead.

Is the base metal carbon or low alloy steel? Is the base metal austenitic stainless steel? Is the issue low temperature toughness or is it creep properties at high temperature? It does make a difference.

Al
Parent - - By Jovi Zhu (**) Date 11-01-2020 23:44
Greetings, Al,

One example:ASME Sect I, PW-40.3.4(d) for repair welding:
"(d) The maximum deposited weld bead width for any electrode shall be four times the electrode core diameter."

One case I heard was someone rejected a wide bead width (not layer), of course he also owed us an answer where the criteria was from. Code or any contract spec... It was just a carbon steel, say SA-106C pipe butt joint.
Parent - - By 803056 (*****) Date 11-02-2020 02:29
That's a special case if I remember correctly that has to do with eliminating the need to PWHT. There are other conditions that apply besides the width of the weld bead as a function of the electrode diameter.

Al
Parent - - By Jovi Zhu (**) Date 11-02-2020 06:36
Exactly, Al. PW-40.3.4 is under PW-40.3 as one of the conditions to make a welding repair after final PWHT before hydro-test.

In EN 1011-2 the following can be found. 

Welding — Recommendations for welding of metallic materials — Part 2: Arc welding of ferritic steels
15 Heat input
Heat input is calculated from the weld travel speed (see clause 19 of EN 1011-1:1998). When weaving with
manual metal arc welding, the weave width should be restricted to three times the diameter of the core rod.
For multi-wire arc welding, the heat input is calculated as the sum of the heat input for each individual wire
using the individual current and voltage parameters.


One confusing thing EN standards bring to me is they consist of many "European manufacturing practice" and without proper interpretation one may fail to distinguish Code mandatory rules, Contract spec., and practice of certain region only.

The above recommendation is not clear on the construciton Code/standard, specfic material grades and other conditions and is often indiscriminately used even as a visual examination criteria to reject a finished welds. Something unfair for the welders is (s)he may not have received any written requirement from a WPS or other work instructions for the weave width until his/her weld is rejected by a customer/3rd party inspector. If this must be followed, should there be some rules for procedure qualification saying a WPS shall specify weave width? In this way the WPS without specified weave width would be rejected when reviewed by the inspector before the weld is made by the welder.

Jsut some thoughts~
Parent - - By Shane Feder (****) Date 11-03-2020 08:41
This is something I published on LinkedIn a while back - maybe of interest or assistance.

SMAW / MMAW Welding – Maximum Weave Width

There appears to be widespread disagreement in the welding community regarding the issue of maximum weave width when utilizing the weave technique for vertical welding.
Maximum weave widths of 3 x the electrode diameter, 4 x, 5 x and even 2 x have been stated.
Where does this recommendation originate ?
That is the million dollar question – nobody seems to know.
Most codes / standards are silent on the issue but the following is what the author has managed to locate.

ASME IX 2000 Addenda:  – Walt Sperko
Weaving: A welding technique in which the energy source is oscillated transversely as it progresses along the weld path.
These definitions use the term “appreciable” to describe the permitted weaving when a stringer bead is required; “slight” weaving is permitted when using the stringer bead technique. When some control of weave is desirable, or when the definition of a stringer bead needs to be addressed, one can use the “classic” approach of specifying “appreciable weaving ”as not greater than 3X or 5X the electrode core wire diameter. A more practical approach is to simply limit the width of the weld bead as it is deposited. For example, one could define a stringer bead as a weld bead not wider than 3/8 inches, and one could limit weave width for weave beads to weld beads not wider than 3/4 inches. This eliminates having to know what size electrode the welder used when he may have multiple sizes, and it provides simple guidance to both the welder and inspectors.

Authors note: Mr Sperko is recognized as a world leader in the application of the ASME IX code and his review comments of the 2000 edition of the code offer an informed opinion.

AWS D1.1 2010 Structural Welding Code – Steel
Table 3.7
Authors note: Per D1.1-2010, the maximum size of a single pass fillet weld in the vertical position is 12 mm.
The maximum size low hydrogen electrode allowed is 4.0 mm.
That gives you 3 x electrode diameter.

What if using a 2.5 mm electrode ?
That is then 4.8 times the electrode diameter

DNV-OS-F101 Submarine Pipeline Systems
D600 Essential Variables for Welding Procedures
Stringer / Weave: Stringer to weave more than three times the specified diameter
Authors note: This is applicable to subsea piping that could be considered a critical application and therefore additional control over weld sizes is to be expected.

ASME VIII Div 1 2019
UCS-56 REQUIREMENTS FOR POSTWELD HEAT
TREATMENT
(f) Weld repairs to P‐No. 1 Group Nos. 1, 2, and 3 materials
and to P‐No. 3 Group Nos. 1, 2, and 3 materials and
to the weld metals used to join these materials may be
made after the final PWHT but prior to the final hydrostatic
test, without additional PWHT…………………
The maximum bead width shall be four times the electrode core diameter

Authors note: This again could be considered a critical application and therefore additional control over weld sizes is to be expected.

ASME 1 2019 rules for Construction of Power Boilers
PW-40.3 Defects in P-No. 1, all groups (if not otherwise
exempted by Table PW-39-1), and P‐No. 3 Group
Nos. 1 and 2 materials, and in the welds joining these materials,
may be weld repaired after the final PWHT but
prior to the final hydrostatic test. The welded repairs
shall meet the requirements below.

(d) The maximum deposited weld bead width for any
electrode shall be four times the electrode core diameter.
Authors note: This again could be considered a critical application and therefore additional control over weld sizes is to be expected.

Why is weave width important ?
The primary issue is heat input.
By widening a weave or changing a stringer bead to a weave bead the forward progression (travel speed) is decreased thereby increasing the heat input.
If heat input restrictions apply no increase is allowed from the heat input recorded on the PQR.
If a WPS is qualified with stringer beads and the welder performs weave welding (and heat input restrictions apply) the weld is automatically non-compliant.
Whereas if a WPS is qualified with a weave technique and the welder performs stringers there is no issue.
This is where the Welding Engineers role is critical.
He/She will determine the best scenario for welding a specific material of various thicknesses with various size electrodes.
They will then decide whether they want the PQR welded with stringers or weaving or if either are acceptable.

In conclusion
Whilst conducting research for this article it became obvious (from numerous internet welding forums) that there is a lot of confusion regarding the “ recommended “ 2, 3, 4, 5 x electrode diameter.
In addition - Is it the completed weld layer width or is it the amount of oscillation allowed ?
IMHO the electrode diameter relationship with the weave width should be disregarded. (except in specific code cases as noted above)
The only thing that is important is the production welding complies with the WPS and the WPS complies with the PQR.
Parent - - By Jovi Zhu (**) Date 11-03-2020 12:04 Edited 11-03-2020 12:37
Shane, Great post giving clues and thanks!

When dealing with contract and Code compliance, ideally one doesn't need to be that overzealous to apply a non-mandatory recommendation from a standard, a customer inspector or 3rd party is simply there to verifiy the compliance. I learned to use "overzealous" to describe such behavior from Walter Sperko's publication, too:wink:.

Before someone jumping out to tell the history of why such rule was set, I'm still not 100% convinced.

If the weaving is wide enough and properly fast, such as when making cover beads of the groove weld, during the travel of arc from one side to the other, weld pool will have enough time to solidify before the arc comes back and partially remelts the previously solidified bead. In this case one is not giving excessive heat input with too slow travel speed, even visually a pretty wide cover bead can be observed.:eek: Or, is there a definition of "weave" limiting the maximum width? I.e., when you are “weaving” too wide, you are not actually weaving but changing the welding direction~

These wording to limit the bead/weave width may be misleading and many reading this would easily get into an assumption of “the wider the beads/weave width, the higher the heat input”.

Al, thanks for the earlier replies and appreciate any ideas or thoughts~

Cheers,

JZ
Parent - - By Jim Hughes (***) Date 11-03-2020 13:59 Edited 11-03-2020 18:20
"These wording to limit the bead/weave width may be misleading and many reading this would easily get into an assumption of “the wider the beads/weave width, the higher the heat input”.
Jovi, I get what your saying. But we have to remember forward motion is the key here. Wider weaves do typically increase heat input, and that is not bad or wrong in certain circumstances.   I think the best way to look at this is to go all the way back to the PQ. What was the objective? Was it just looked at as a task? Or was there thought put into what we need to achieve? i.e. heat input controlled due to CVN's or hardness or other considerations?  Based on conditions that you find yourself in you can write a WPS off of a PQ and address restrictions or other non-essential variables as needed. As others have said using the code as giving you direction for everything welding is a mistake. There are some codes that do give restrictions, and you sited one. ASME Sec I.   Ultimately, ASME is concerned that an end user of their code can prove they can make a sound weld and have the ability to pass that information on to the welder.  Is what you are wanting to do based on data? or is it tribal knowledge or here in Texas " that's the way we always have done it"

If Hamlet was alive today maybe his quote would have been "to weave or not to weave, that is the question":grin: But seriously only you, the end user can answer that, and in my opinion not a third party inspector that was not involved in the qualification of the procedure. Maybe in the spirit of client relations you can give some ground, unless your WPS says no.
My thoughts anyway.
Parent - By Jovi Zhu (**) Date 11-03-2020 15:51
Jim, Thank for the post and your Hamlet quote:lol:. I'm trying to pause the digging of the technical reason of it.
"That's one small motion for a man, causing too much emotion for mankind" :grin:

My thought goes with some welders I used to work with who were proud of their workmanship and the way they weave the SMAW stick with weld ripples and patterns creating thier own aesthetical standards. Just trying to make sure technical terms are not indiscriminately applied for a certain condition, unecessarily killing the pride of the workforce.

JZ
Up Topic Welding Industry / ASME Codes / bead width concern

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