Mig wire chart?

[Davek0974]

Hi all,

I usually have ER70s wire in my Mig, I think it's a general purpose wire?

However, I have to make some stuff from steel called CorTen, it's only 3mm thick but it seems I need wire marked SG2?

I cant seem to find a comparison chart for Mig wires, is there such a thing and for my task is it worth getting the new wire in or not??

These are architectural garden stuff, nothing structural.

 

[Spark plug]

Ive never seen a mig wire chart but this may help, if you haven't seen it already.

http://www.mig-welding.co.uk/corten.htm

 

[Davek0974]

Ive never seen a mig wire chart but this may help, if you haven't seen it already.

http://www.mig-welding.co.uk/corten.htm

Thanks.

I think I have ER70s3 at home in the Mig (can't guarantee that yet though)

ER70s-3 has these properties...
C = 0.06-0.15%
Si = 0.45-0.75%
Mn = 0.90-1.4%

SG2...
C = 0.06-0.10%
Si = 0.70-0.10%
Mn = 1.26-1.54%

So would those small differences really make much difference?

 

[Welderpaul]

Either SG2/SG3/whatever wire won't matter for the job.....but.....the welds won't weather the same as the parent metal. After a while the weld metal stand out like a sore thumb.
We made some big planter boxes from 20mm plate a while ago and ended up using E8018's to weld it up so the weld's didn't show.

 

[Davek0974]

But the link above recommends SG2 for sheet less than 10mm thick?

Is there a Mig equivalent of E8018???

 

[Davek0974]

Got this from the Corten website...

"If the base and filler materials mix sufficiently to provide good weathering resistance, ordinary non-alloyed consumables can be used. Sufficient mixing is achieved in single run welding of under 4mm plates for butt joints, and for fillet wields with a design throat thickness of up to approximately 4 mm. "

As I'm only doing 3mm sheet, butt and fillet, should be ok?

 

[TechnicAl]

ER70S-3 and SG2 are similar enough in this case. Either will be OK
Welderpaul welded 20mm plate which will be multi pass so needs a filler wire containing Ni and Cu (or higher Ni) as recommended in the link. It looks like he didnt listen and you could see the welds (tut tut Paul). To be honest Im glad to hear his comments.......they confirm the recommendations made in the link.

 

[Davek0974]

Great,

Just had a look and I have two reels of ER70S-6 and one of SG2 so should be ok

 

[Dimitri De Spiegeleer]

SG2...
C = 0.06-0.10%
Si = 0.70-0.10%
Mn = 1.26-1.54%

Are these Si-contents correct? they are usually toleranced up to 1.0% or even a tad higher.
SG2 is the standard wire to weld structural steel with.

As said aboves, SG2 will very likely work just fine as long as it's diluted enough to take up the copper contents of the base metal.

 

[Davek0974]

Are these Si-contents correct? they are usually toleranced up to 1.0% or even a tad higher.
SG2 is the standard wire to weld structural steel with.

As said aboves, SG2 will very likely work just fine as long as it's diluted enough to take up the copper contents of the base metal.

Oops it's 0.07 to 0.10.

I'll try the sg2

 

[Dimitri De Spiegeleer]

That's very, veryy low for SG2.
What is the manufacturer? I'd like to know what their reason is for that...
If you encounter hot cracking, change for a filler metal with higher silicon and manganese contents...

 

[Davek0974]

I think it may be a double oops, 0.7 - 1.0

 

[TechnicAl]

Thats better..........dont worry it wont be as you posted earlier..........if it was your welds would be full of holes

SG2, ER70-S6, ER70S-3, A18, G3Si1..........are all similar enough to do your job