Edge preforming of metal plate

摘要

Method and means for preforming the long edges of steel plate prior to manufacture into pipe by the U-O Process or the like by utilizing plate of a width exceeding that required for pipe of a given diameter by an amount at each edge having an excess at least equal to the width of the pipe. Roll-forming the plate to use the excess [at least equal to the width of the pipe. Roll-forming the plate to use the excess] width thereof as a lever arm to obtain a bend at the bitter edges of the pipe (edges required for pipe) of a radius required for the pipe and thereafter shearing the plate to form the bitter edges, followed by bevelling and polishing the bitter edges, and further roll-forming the edge area to complete the preform thereof.