Artists join two pieces of steel when making a sculpture by welding them together. Welding uses intense heat, and sometimes pressure or added filler metal, to create a permanent joint as the materials cool and solidify.
Welded sculpture became especially important during the 20th century, when artists began treating industrial materials as artistic media. Russian artist Vladimir Tatlin is credited with some of the earliest welded sculptures, beginning around 1913. Julio González later helped establish welding as a major sculptural technique, and artists such as Pablo Picasso, David Smith, Alexander Calder, Anthony Caro, and Richard Serra expanded its possibilities.
Welding differs from casting, another common metal-sculpture process. In casting, molten metal is poured into a mold; in welding, separately shaped pieces are assembled directly. Artists may cut steel plate, bend rods, grind the seams, and leave the welds visible or smooth them away. Bolts, rivets, brazing, and mechanical fasteners can also join metal, but welding is the standard single answer for joining steel pieces in a constructed sculpture.