... welding wire ER70s-6 welding carbon steel,500MPa high strength steels,welding in cars,building,bridges SG2 copper coated co2 welding wire AWS ER70s-61) welding wire ... 1kg,5kg,15kg,18kg,20kg chemical composition of welding wire(%)CMnSiPSCrNiCu0.06~0.151.40~1.850. ... welding to avoid the wire rust.Before welding please clean out the oil,rust,water etc from the work parts SG2 copper coated co2 welding wire ...