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Up Topic Welding Industry / ASME Codes / ASME Sec VIII Div 1 question.
- - By Kix (****) Date 10-16-2015 18:54
During visual examination of a stainless steel vessel I witnessed carbide precipitation or sugaring on a circumferential butt V-groove weld welding 304L to 304L with ER308L filler in the root pass inside. Within the spec, the only VT criteria I can find is in UW-35. I can't find anything that speaks to oxidation, carbide precip or sugaring. In saying that, can this be rejected? This weld is not being RT'd so can the criteria in UW-35 be used?
Parent - - By TimGary (****) Date 10-16-2015 19:10
Do the project specs require back purge to prevent oxidation on SS welds?
Parent - By Kix (****) Date 10-17-2015 14:31
Tim, the approved WPS requires back purge. The root on the inside has a few spots where the purge must have been insufficient and it sugared. They're pulling the ol, where does it say we can't have any sugar because they just don't understand.
Parent - - By CWI555 (*****) Date 10-17-2015 11:34
If it is sugared, it's highly doubtful a wps was followed correctly. The code assumes a wps/pqr was utilized. That would be the angle I'd take on something like that as sugaring is not specifically addressed to my knowledge visually.
Parent - By Kix (****) Date 10-17-2015 14:33
That sounds like a perfectly good way to go. Thank you.
- - By 803056 (*****) Date 10-17-2015 17:05
The surface oxide (chrome, iron, nickel oxides) does not affect the mechanical properties specified by the code. The oxide, if left in place, will adversely affect the corrosion resistance once wetted with an electrolyte. If it is a dry environment, no harm, no foul.

Corrective action simply requires the removal of the oxidized surface by mechanical means such as sanding with a soft pad or grinding or by chemical means. There are several chemical solutions available to remove surface oxides.

Sugaring, carbide precipitation, decarburizing, three terms that should be banished from use here in the Forum. The oxidized surface has nothing to do with sugar or carbon.

Best regards - Al
Parent - - By Kix (****) Date 10-19-2015 14:43
Al,

The only thing I made them do for the rework was to remove the oxidation by grinding. I just had to have reason per code requirements to back it up and could not find any. The piping will have water more then likely with a glycol mix flowing through it. I'm also confused in your statement about cabide precip and oxidation. Are you saying that they are one in the same or that they are different and sugaring or whatever you want to call it should be called something else? Here is a picture of what the root looked like more or less. http://www.grumpysperformance.com/weld%20crystalizing.jpg

Kix.
Parent - - By 803056 (*****) Date 10-19-2015 15:18 Edited 10-19-2015 15:20
Exactly! The terms sugaring and decarborizing lead people to believe the problem is caused by the something it isn't. What you are seeing is simply oxidized metal, i.e., the iron, chrome, and nickel and whatever else is exposed to air while the metal is in the molten state or while at high temperature.

You are doing the correct thing in making them grind the surface to remove all traces of the oxidized material. If any oxidized material is exposed and then placed in a wetted environment, galvanic corrosion can occur.

Nice photos by the way. Do you mind sending me copies?

Al
Parent - - By Kix (****) Date 10-19-2015 15:28
Interesting. I was always taught that what you saw in the picture was carbide precip. I e-mailed you that picture.

Thanks again,

Kix
Parent - By 803056 (*****) Date 10-19-2015 15:52 Edited 10-20-2015 14:42
Excellent - Thanks for the photo.

That's exactly why I hate to hear people call it anything other than what it actually is. It has nothing to do with carbon or sugar.

Best regards - Al
Parent - By Lawrence (*****) Date 10-19-2015 17:51 Edited 10-19-2015 17:55
Ok,

So the "oxidation" on the weld root here in the pic is pretty intense.

I would like to have seen the root surface after mechanically removing the oxidation completely.

In my experience, even on a flat surface, when oxidation like shown above is removed, the face of the root bead is either still non-conformant due to porosity, or the cross-sectional thickness of the base metal has been reduced by chasing the oxidized surface by rotary filing.

That oxide will tear up a flapper or a scotchbrite leaving nothing but powder, dust and an oxidized root reinforcement that looks pretty much untouched :)

The Carbide Precipitation is a grain boundary thing :)
Parent - - By Lawrence (*****) Date 10-19-2015 18:00
"The root on the inside has a few spots where the purge must have been insufficient "

A FEW SPOTS ?!?!?!
Parent - By Kix (****) Date 10-19-2015 19:44
Ha HA, you made me laugh man. That picture is not of the weld I was talking about on the vessel. I just used that as an example. An exaggerated example none the less. Yes, A few spots looked like the picture. :lol:
Parent - - By Lawrence (*****) Date 01-14-2016 19:27
I know, it's an old thread.. But this term "sugaring" comes up time and again.

Was scanning AWS Visual Inspection Workshop Reference Manual 2008 today and found "figure 2.37-- Surface oxide "Sugaring") in a stainless steel Gas Tungsten Arc Weld."

Text for the figure excerpted as follows:
"Surface oxidation of stainless steels and nickel alloys occurs whenever these alloys
are exposed to the atmosphere while above 1000F known as sugaring when it becomes heavy.

I know this is an ASME context thread... But thought there might be some interest in the fact that that offensive word is actually found in some official context.
Parent - - By aevald (*****) Date 01-14-2016 20:50
Hello Lawrence, does that mean that some of us are at least slightly vindicated for the use of the word? Best regards, Allan
Parent - - By Lawrence (*****) Date 01-14-2016 21:23
Nope:    Al said we couldn't  :)
Parent - - By aevald (*****) Date 01-14-2016 23:04
Well......OKAY, Allan
Parent - - By 803056 (*****) Date 01-14-2016 23:25
Usually a word enclosed by " " indicates the word is considered to be a nonstandard term.

Even AWS standards have been known to use nonstandard terms now and again.

Al :razz:
Parent - - By aevald (*****) Date 01-15-2016 03:33
Hello Al, I find myself having mini-sit-downs with students on a regular basis anymore explaining the need for standardization of terminology. Before I had access to this forum and other sources I was just happily oblivious to many of these ins and outs. Now you and a host of others have "forced" :) me to reconsider many statements and positions. Thank you to you and others for that. My students may eventually come to the realization that these sort of things can "matter" too. Best regards, Allan

P.S. when I do use non-standard terminology I also provide the correct terminology and go into why it is important to understand the ramifications of the differences. My reason for referring to non-standard terms is to explain to them that various shops that they may end up in may not be up to speed on terminology and thus they are provided with the ability to be in a possible position of change.

SORRY TO THE OP FOR THIS DE-RAILMENT OF THE THREAD!
Parent - - By 803056 (*****) Date 01-15-2016 04:11
You are not alone my friend.

I include slides of several weld defects in my presentations that use both the proper terminology and the slang terms to make sure the student can communicate with other people that may not be familiar with standard terminology. After all, the intent is to communicate with people. One must be familiar with the proper terminology if there is a need to be "professional" and there is a time to use nonstandard terminology when clarifying the meaning to someone that is not familiar with the standard terminology.

A professional will recognize the terms "root face" and "land" are the same part of a groove detail, but I would not expect the term "land" to be used in professional communications.

The use of nonstandard terminology simply complicates effective communication. Are you familiar with the term "dry pass"? If not, communication is interrupted when you have to ask for clarification. Communication becomes inefficient and can lead to misunderstanding and miscommunication. As a last resort, one would have to seek clarification in the New Farm Code (oops, I meant to say D1.1).

Best regards - Al
Parent - - By aevald (*****) Date 01-15-2016 04:18
Thanks Al, enjoyed the reply immensely. Allan
Parent - By Superflux (****) Date 01-15-2016 14:19
Well,
If y'all woulda just "Arc Welded" it, there wouldn't be no "Sugaring"....
Parent - - By js55 (*****) Date 01-15-2016 14:57 Edited 01-15-2016 15:01
There will always be "non-standard" terms in wide spread usage. This is because welding is more than simply a trade. It is a culture. And the people immersed in this culture will develop their own ways of communication. The vernacular. Or, the best term for it, that I discovered recently, is 'exosemantic'. It is a group identification. In other words, its use is as much driven BY THE VERY FACT that it is "non-standard".
And as technologies change so the culturally driven "non-standard" exosemantic terms will change to accommodate them.
Rules people, the paper people, people not immersed in the culture, will come along and try and 'clean up' all this supposed non-communicative cultural messiness. This is fine. It gives them something to do.  :grin:
Parent - - By Lawrence (*****) Date 01-15-2016 15:53
Good points

I serve about 400 welders (the guys who actually make the profits)

Whether I adopt their terms or they adopt my terms isn't all that important.  But we do need to understand one another.  So we do put some effort into creating that culture/language.
Parent - - By js55 (*****) Date 01-15-2016 16:18
Lawrence,
I make a point of trying to use standard terms in all of the documents, procedures, and reports I generate. But I am also acutely aware that if I am to impose something upon a shop environment it is at least as important that I understand those in the welding culture, as it is to get them to understand me.
Of course, since I came from the welding culture it comes easier. Though my eyes aren't as good as they used to be. And its been many moons since I was under a hood. And my ass is fatter because of it.
Parent - - By 803056 (*****) Date 01-16-2016 00:52
You have the luxury of working with a captive crew. As long as everyone is on the same page, all is good. However, I'm working with welders in about 40 states and in some cases overseas. A common language, i.e., standard terminology, is essential to effective, efficient communications. If I use a term they are not familiar with, they can refer to a standard that is pretty well recognized internationally, i.e., AWS A3.0. That one document defines the terminology common to the welding industry.

I am forced to ask if those using nonstandard terminology have a similar reference that can be used to look up terms that they do not understand? I guess they can always look in the "Old Farm Code". I don't know that the "New Farm Code" would be of much value to them.

As an example I tossed out the term "dry pass". How many of the folks here in the Forum know the meaning of that term? Yet it is pretty well known by the 2000 or so welders in that one company. That's fine until they try to communicate with welders, inspectors, and engineers from another company. It makes it rather difficult when working with subcontractors and vendors that have no clue as to what the term means. Where do they go to find out what the term means?

Best regards - Al
Parent - - By js55 (*****) Date 01-18-2016 12:58
Were it me,,,,,I'd go to you Al.  :wink:
Parent - By 803056 (*****) Date 01-18-2016 23:38
:grin:

Al
- - By ANKIT.642 Date 01-09-2016 07:25
Hi, I am designing a vessel. In which found the shell thickness as per UG27(c )  12 mm (nominal) and head thickness as per appendix 1-4(d) 14 mm (nominal). Now as per UG 32 (k) I have to provide sufficient skirt length to meet the requirement of fig. UW-13.1 ( be specific in my case fig. UW-13.1 (L) ). 

So , is it necessary to provide the taper transition UW-9 and UW-13 (b) (3)?? 

If yes, then what’s the length of the skirt length and type of the taper transition.
Parent - By Don56 (**) Date 01-11-2016 22:32
See UW-9 & UW-13.
Parent - By ssbn727 (*****) Date 01-17-2016 12:41 Edited 01-19-2016 22:55
Greetings ANKIT.642!                                                                                                             

In the future, if you have different issue than what is being discussed on a thread such as this one. Please feel free to start your own thread so as to avoid any confusion with the topics being discussed. And you can place it in the appropriate section for your query. In any event, may I "Welcome" you to the worlds greatest welding forum of the American Welding Society!:grin::cool:            

Respectfully,
Henry
Up Topic Welding Industry / ASME Codes / ASME Sec VIII Div 1 question.

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