An AWS A5.1 stick electrode number reads like a spec sheet. The first two digits give minimum tensile strength in ksi — E60xx is 60,000 psi weld metal, E70xx is 70,000 psi. The third digit is position, with 1 meaning all-position. The last digit encodes the coating chemistry and the current it can run on: E6010 is cellulosic and runs DCEP only, E6011 is its AC-capable twin (both punch through rust, paint, and galvanizing better than any other common class), E6013 is a smooth rutile rod happy on any polarity, and E7018 is the low-hydrogen workhorse run DCEP or AC.
What the classification does not fix is amperage. Current windows are manufacturer data published per product, and they genuinely differ between brands of the "same" rod — Lincoln rates its 5/32 in E7018 at 130–210 A while Hobart’s spans 110–230 A, because each maker’s flux chemistry, iron powder content, and arc drive differ even though the AWS class fixes the weld-metal properties and coating family. The overlap of two published ranges is a window safe on either brand; the full printed range is only guaranteed for that manufacturer’s own rod. SMAW itself — the process these classifications belong to — is the AWS designation for stick welding, where the burning flux coating generates the arc’s own shielding.