The process of a pipe production is the following: a round cast workpiece is put onto a hot rolling line where it is cut, heated, stitched and rolled till a pipe of necessary size is ready.

In order to measure the cylindricity error of the pipe which is in the internal part of a workpiece, this paper studies a cylindricity error evaluation method based on industrial CT images.

For a workpiece used in expanding the beginning of plastic pipe, We analyse the machining process, workpiece rectifying before machining, and design WEDM processing and its program.