I kind of had the impression that you used 70s6 for your run of the mill mild steel and 70s2 for things like 4130 tube.
Recently watching some video on YouTube a fellow was showing off his skills and welding up some mild steel welded square tube with ER70s2. I had just asked the manager over at the local Praxair store what the practical difference was, and he said basically what I said in the first sentence of this post.
So anyway, what is the real world general application of the two types of wire?
I know. I know. Go melt some wire and see what happens. LOL.
Ok... now I am confused. A few people got back with me on this and they basically said they had seen ER70S6 tig wire maybe, but they hadn't seen an application for it. Here in this video
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he is laying in an open root pass with ER70S6 TIG wire in preparation for a 7018 cap pipe welding in the
2G position. The guys at Weld.com (source of the video) usually are spot on with their information. So how would he have made the choice to use ER70S6 for that application? Its well cleaned up in prep for the weld, so S6's ability to deal with a little mild scale etc would not have been a factor.
70S6 has more de-oxidizers in it. Better for metal that is not spotlessly clean. I use it for everything. 70S2 is good for brand new metal that you then ground and cleaned even more before welding. Both are 70Kpsi strength.
specs on 70s6:
AWS Chemical Composition Requirements
P = 0.025 max V = 0.03 max S = 0.035 max Cu = 0.50 max
Application Type ER70S-6 is a wire with higher levels of Deoxidizers welding of steels with moderate amounts of scale or rust. (Mn & Si) compared to other carbon steel wires. This wire is suitable for welding of steels with moderate amounts of scale or rust.
70s2 specs:
AWS Chemical Composition Requirements C = 0.07 max Ni = 0.15 max Cu = 0.50 max
S = 0.035 max
Available Sizes .035 x 2#, 11#, 33# .045 x 2#, 11#, 33#
1/16 x 33#
Application Type ER70S-2 is a triple deoxidized steel welding wire for tig and mig welding applications.
70s3 specs:
AWS Chemical Composition Requirements
P = 0.025 max V = 0.03 max S = 0.035 max Cu = 0.50 max
Available Sizes .023 X 11#, 33# .035 X 11#, 33# .045 X 11#, 33# & 60# Coils
Application Type ER70S-3 is a welding wire for tig and mig welding applications.
For Mig welding use Carbon Dioxide or Argon + Co2 or Argon + 2% Oxygen as shielding gases.
The above are from
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Kind of odd, I had thought that 70s6 had aluminum in it as a deoxidizer. 70s2 has the lowest amount of carbon.
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