Welding electrodes are metal wires with baked on chemical coatings. The rod is used to sustain the welding arc and to provide the filler metal required for the joint to be welded. The coating protects the metal from damage, stabilizes the arc, and improves the weld. The diameter of the wire, less the coating, determines the size of the welding rod. This is expressed in fractions of an inch such as 3/32", 1/8", or 5/32." The smaller the diameter means it requires less current and it deposits a smaller amount of filler metal.
"E" indicates "electrode" for electric arc welding
The first two (or three in some cases) digits (60) indicate tensile strength in thousands of pounds per square inch
The third (or fourth in some cases) digit (1) indicates the position of the weld. An "O" indicates that this classification is not used; "1" is for all positions; "2" is for flat and horizontal positions only; 3 is for flat position only
The last two digits together (10) indicate the type of coating and the type of power supply required, 10 organic coating and DC current with reverse polarity.
Therefore, a welding rod numbered E6010 indicates "E" an manual arc-welding electrode with (60) a minimum strength of 60,000 psi., that can be used (1) in all positions and (10) DC reverse polarity is required.