ISO 3581:2016 specifies requirements for classification of covered electrodes, based on the all-weld metal chemical composition, the type of electrode covering and other electrode properties, and the all-weld metal mechanical properties, in the as-welded or heat-treated conditions, for manual metal arc welding of stainless and heat-resisting steels.

It is a combined standard providing for classification utilizing a system based upon classification according to nominal composition or utilizing a system based upon classification according to alloy type.

a) Paragraphs and tables which carry the label "classification according to nominal composition" or "ISO 3581-A" are applicable only to products classified to that system.

b) Paragraphs and tables which carry the label "classification according to alloy type" or "ISO 3581-B" are applicable only to products classified to that system.

c) Paragraphs and tables which carry neither label are applicable to products classified according to either or both systems.