Seamless pipes are manufactured using different procedures, depending on the diameter or the ratio of diameter to wall thickness. The normal raw material is a round spool section preheated in a rotary furnace, or for larger diameters a hollow section preshaped in a perforation press, which is then prerolled in a rotary rolling mill. The wall thickness tolerance of 12.5 % for hot rolled seamless pipes is specified fundamentally in ASTM A999 or EN ISO 1127 T2. However, wall thickness differences caused by the manufacturing procedure may lead to a possible eccentricity. When manufacturing seamless pipes, the length manufactured depends on the weight per metre or per rod. Thus up to NB 100, pipe lengths of a maximum 13 m, and up to NB 200 pipe lengths of a maximum of around 4 m can be produced.
The condition of the surfaces of seamless pipes is determined by the hot forming. Thus subsequent grinding, necessitated by the “orange skin” which occurs with this production process is only possible at a higher cost. In Seamless pipe, there are no welding or joints and is manufactured from solid round billets. The seamless pipe is finished to dimensional and wall thickness specifications in sizes from 1/8 inch to 26 inch OD. Applicable in for High-pressure applications such as Hydrocarbon Industries & Refineries, Oil & Gas Exploration & Drilling, Oil & Gas Transportation and Air and Hydraulic cylinders, Bearings, Boilers, Automobiles etc.