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Up Topic Welding Industry / Technical Discussions / 308/316lsi
- - By mikew (*) Date 01-29-2004 00:28
HI , the co. i work for started buying 308/316lsi several months ago, instead of 308l/316l . I'm not sure why ,I imagine they have gotten agood price on it or something?!
What are the advantages and disadvantages of using 308lsi. and what does the addition of si provide?
We use it for gmaw-p and the first time i welded with it I immediately noticed that the arc seemed less defined and it seems to leave a kind of smokey black residue on each side of the weld (which is easily wiped off). I have not tried gmaw-s with it yet though.
(We use a ar/co2/hydrogen mix gas to pulse with . )
We recently bought some 308lsi to run on our subarc. so i would also like some input on what that might do for us(instead of just 308l)
ANY and all help/advice would be greatly appreciated
thanks in advance,
mike wright
Parent - - By Niekie3 (***) Date 02-01-2004 14:16
Hi Mike

In South Africa, we mostly use the Si grade for GMAW while the streight 316L and 308L grades are used for GTAW. The idea is that the extra Si helps with weld pool manipulation during GMAW when using a gas with active gas additions.

You should not really be able to see any effect on the arc, and it certainly should not leave a significant black residue. Maybe there was something else that also changed?

Regards
Niekie Jooste
Fabristruct Solutions
Parent - - By mikew (*) Date 02-01-2004 23:20
niekie ,
your are right i did not think it should have an effect on the arc , so i changed wires (back to308l) and the arc seemed better again.Needless to say it is still puzzling?!
I tried different gas mixtures a(98/2,tri-gon),which did help with the residue but not with the arc.
Does the addition of si help remove contaminants inthe base metal as in 70s6 for carbon?
thanks for your help,
mike wright
Parent - By Niekie3 (***) Date 02-03-2004 18:03
Hi Mike

I really do not think that the Si will be added for "cleaning" the weld, because S/Steel is generally not welded with too much CO2 in the gas. (Just a little sometimes.) Rather, it helps with weld pool fluidity.

Regards
Niekie Jooste
Fabristruct Solutions
Up Topic Welding Industry / Technical Discussions / 308/316lsi

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