... wall thickness welded pipes HG20 welded pipe making machine: 8-25mm outer diameter, 0.3-1mm wall thickness welded pipesGeneral Processing {Steel ... of driven stand: 42CrMo, Φ38mm diametershafts of vertical roller: 42CrMo, Φ25mm diametermaterial of gearbox: cast ironmaterial of gear: 20CrMnTiBetween forming unit ...