Method of forming pipe spigot ridge

摘要

A method of forming a ridge around the outer circumference of a spigot formed at an end of a pipe. A ring having a certain wall thickness in its radial direction and formed with a peripheral groove on its outer circumference is placed around the outer circumference of the spigot. Then molten metal is poured into the peripheral groove, so that the bottom of the peripheral groove and the surface of the spigot are melted, thus joining the ring and spigot together.