what is the difference between e6013 and e7018_7018 electrode

Submerged-Arc Welding Wire is a type of welding wire that has been specifically designed for use in SAW applications. It is a metal wire, typically made from copper or stainless steel, that is submerged in an electric arc to create the weld. This method of welding provides many advantages over traditional arc welding techniques, including higher strength and improved penetration depth. Additionally, it produces cleaner welds with fewer porosity defects than other methods.