Discussion on Modification of CPE Process

Described here in the essay are the currently-used main operation steps of the CPE pipe mill.Relevant modification suggestions are put forward，including on-line mandrel extracting with a clasp（block fork），on-line mandrel loosening by planetary mandrel loosening mill，off-line pipe extracting by extracting mill，replacing the 3-roll die with the 4-roll die，and pointing via spinning process to reduce metal loss from cropping，etc. Relevant analysis leads to the following conclusion. Thanks to the on-line mandrel extracting/loosening operation steps，the manufacturing process flow will be shortened，the shell temperature raised，and the mandrel service span expanded，while due to replacement of the 3-roll die with the 4-roll die，the inner profile of the pipe as sized（reduced） will be turned from“the hexagonal”into“the octagonal”，and thus the pipe’s wall thickness accuracy will be improved.