Lugged steel frame construction is a method of building
bicycle frames using
steel tubing mated with socket-like sleeves, called lugs. For most of the
bicycle's history, steel has been the primary material for bicycle frames, with lugged construction the primary assembling method. Steel continues in use by builders of high-quality steel frames, though its dominance as a frame material has waned since the mid-1990s – displaced largely by aluminum and
TIG welding.