When anon-standard size cylinder is required (either a special OD or a thicker wall than the tube can be made from a hot rolled tube with specific quality features. Two processes are necessary to transform a normal hot rolled tube into a tube suitable for cylinders, the tube must be bored first and then honed to reach ID tolerance H8 according to EN 20286. The mechnical and chemical properties of these tubes are still those of the base tube.
Size and tolerance:
OD.,wt and outside straightness follow the tolerances stated by the norm EN10297-1The tolerances on the I.D.are ruled by tolerance H8 according to EN 20286 instead,as resumed here below.