The submerged arc weld in HSLA line pipe is examined by briefly reviewing the metallurgy of high strength low-alloy steels and then considering how the welding process affects this metallurgy.Particular emphasis is given to the influence of thermo-mechanical processing and to the role of micro-alloy additions as they relate to strength, grain size, and toughness. The metallurgy of the weld is contrasted to that of the base plate, and some recent investigations are reviewed.The influence of consumable selection is considered, and some recommendations for further study are made.