Digital Imaging of an ERW Pipe Forming Process

A deformation analysis of an ERW forming operation for a 114.3 mm (NPS 4) diameter steel pipe was undertaken using digital imaging technology. Digitals images taken of the inside profile of the pipe were calibrated and converted into Cartesian coordinates and a profile map along length of the forming operation was generated. A numerical curve fitting technique was applied to each individual profile to calculate the circumferential strain around the inside diameter. The circumferential strains calculated using the digital imaging technique corresponded well with strain gauge measurements. The calculated strains were combined into a 3D contour plot of strain along the length of the ERW process.