Patent attributes
A welded pipe joint having reduced internal stresses comprises a pipe, a socket fitting, and an annular weld. The end surface of the fitting is chamfered in a concave profile, so that the weld profile subtends an angle of from about 100 degrees to about 120 degrees, rather than the customary 90 degrees. The fitting and the pipe are welded together by applying, from outside the pipe, an annulus of added bead metal to the chamfered end surface of the fitting so as to surround the chamfered end surface, and fusing the base metal of the annular wall and pipe. The pipe has no dam or other protuberance to confine the bead of added metal. Prior to welding, the fitting may have an annular lip immediately surrounding the surface of the pipe and may also have a ring spaced from the lip. The ring may be integral with the fitting and spaced from the lip by thin, radially spaced metal bars or may be separate from the fitting.
