​Specifies materials of construction, weld preparations, weld qualities, qualification of welding procedures, qualification of welding personnel, and fabrication and inspection requirements for welds related to the arc welding of steelwork in structures made up of combinations of steel plate, sheet or sections, including hollow sections and built-up sections or castings and forgings. Tables of weld preparations are given for both butt and fillet welds which when welded in accordance with other specified requirements are deemed prequalified and do not require qualification testing. Provides two categories of welds based on the type of application.