Weld pool commonly refers to the dime-sized workable portion of a weld where the base metal has reached its
melting point and is ready to be infused with filler material. The weld pool is central to the success of the welding process. It was first observed in
oxy-fuel welding by Fouché & Picard in 1903, after the discovery of
acetylene by
Edmund Davy in 1836.