mig wire for roll cage

[TAITSIE]

Anyone used ER 100 S-G grade wire for welding up a rollcage made from T45 tube.
If so what gas do you use and is there anything to watch out for?

 

[davenport]

T45 should be done with either A31 or A32 filler wire...

http://www.customcages.co.uk/roll-cages/frequently-asked-questions

 

[TechnicAl]

You can weld it with plain mild steel SG2 / A18. The weld will be thicker than the tube and therefore match (or overmatch) the strength. If the weld was the same thickness A31 or A32 would be a good match. The 100S-G is overkill and at the extremes could lead to fatigue failure (but its a long way off)