Sir,
With all due respect – a commendable, enjoyable, respectful and profound read.
I do agree. This is one of the lessons that I was allowed to learn here quite early. It is the American Welding Society Forum and good that is. I do not really know any other forum dealing with our trade in such a remarkable, yes I'm almost tempted to say, honourable way.
That, in my opinion, may also be one of the reasons for that it is attracting persons obsessed with welding, even from way beyond the pond.
I do agree. As such, being the AWS forum, specific AWS terminology/nomenclature complying with AWS codes and standards should be recommended being used. Simply for achieving common understanding – entirely independent of ones personal "agreement" or "disagreement" as when it comes to the particular welding/joining topic dealt with.
Nonetheless, couldn't I read somewhere recently, "
No one works in a vacuum"?
Hence, I stick to this. The AWS in my eyes wouldn't be the AWS if it would "exist in a vacuum". On the contrary I suppose moreover it is the open discussion with all these different "organisations" and those fellows from around the world, that considerably contributes to its excellent reputation.
This, amongst others, was the reason for me granting "46.00" some humble though but honestly meant comment.
Anyway, coming back to these "
few relevant definitions extracted from AWS A3.0-2010 Standard Welding Terms and Definitions" for:
• "
Slag: A nonmetallic product resulting from the mutual dissolution of flux and nonmetallic Impurities in some welding and brazing processes."
I should like to stick to the term "nonmetallic impurities" asking moreover, as the Welding Institute's had not particularly covered that in depth; if nonmetallic impurities may cause "slag" to occur and the TWI parent metals (autogeneously welded without employing "fluxes"), wouldn't it be possible then that the sort of "contamination" found along with this study may have been caused through "nonmetallic" parent metal impurities (whatever these were)?
Provided that is so. May we then use the AWS A3.0-2010 Standard term "slag" for what's been found adhering to the weld bead surface?
We could negate this question immediately, when, (and this is just mentioned in order to provide a rather more complete picture) instead of using AWS A3.0-2010, we would comply with the British Standard BS 499-1:2009' definition of "slag" which is stated as:
• "
Non-metallic substance that results from fusion of an electrode covering, a flux core or a powdered flux and which, after solidification, partly or totally covers the weld metal".
Further to AWS A3.0-2010.
• "
Slag Inclusion: A discontinuity consisting of slag entrapped in weld metal or at the weld interface."
From the aforementioned I dare to suggest then that, provided were allowed using the AWS "slag" term, this definition just implies that TWI has found (in this particular case employing these particular boundary conditions) "slag" irregularly deposited across the bead surface.
Returning to BS 499-1:2009 that defines "
inclusion" as:
• "
Slag, flux, oxide, copper, tungsten or other foreign matter entrapped during welding; the defect is usually more irregular in shape than a gas pore; inclusions can be linear, isolated or clustered in their formation."
And, something that may eventually fit approximately in to the "non-standard" term "slag track", i.e. "
linear inclusion" ("
slag line") as:
• "
Inclusion of linear form situated parallel to the axis of a weld."
Of course I have to admit. This is confusing at the very least, since TWI = Most Honourable British Institution should have referred to British Standards - I suppose.
As a logical consequence the appreciated fellow that had written the final report should
not have made use of the term "slag" for describing his contamination findings.
However, considering the study conducted in 1988 or so I’m certainly unable to say
how "slag" was defined at that time in compliance with British Standards.
Finally I do respectfully agree with another part of your statement: "
... that's what I call an interesting conversation."
That it is.
Thank you.
EDIT: According to the statement of 'MMyers', saying: "
...this thread is kinda useless without a reference link back to the original discussion, paper being discussed..." which I fully agree to, I should like to attach the corresponding link that, in my understanding and amongst others, may have caused this thread:
http://www.twi.co.uk/news-events/bulletin/archive/pre-1998-articles/1988-articles/how-tig-welding-procedure-affects-penetration-and-slag-island-formation-part-1/.