Origins and development: The process, The first twenty years; Development after 1955. Principles: Equipment, Joint preparation and welding procedure; Welding conditions; Special techniques; Weld defects. Process variants: Single electrode welding; Multiple electrode welding; Metal powder additions; Narrow gap submerged-arc welding. Consumables: Types of flux and their development; Wires; Flux/wire combination; Consumables for different steel types; Flux delivery system. Welding procedures: Welding costs; Establishing a procedure; Procedural options; Application and uses of optimisation; Heat input.