The structure of a welded joint of stainless steel 316L is studied by the methods of scanning electron microscopy including microprobe x-ray spectrum analysis and diffraction of backscattered electrons (EBSD). It is shown that a double-phase structure forms in the region of the weld including high-temperature δ-ferrite and austenite. The austenite and the ferrite undergo recrystallization in direction
parallel to the heat removal. The presence of high-temperature δ-ferrite in the steel results in nonuniform distribution of the alloying elements (Cr, Ni, Mo) and in appearance of phase boundaries, which can reduce the corrosion resistance of the welded joint.