Thick-walled tubes: Produced by horizontal centrifugal casting process with a metal mold, outer diameters ranging from Φ500 to Φ1580 mm, single tube length of 12500 mm, with a tube wall thickness of less than 350 mm, duplex steel, stainless steel thick-walled tubes, vacuum pressurization rollers for papermaking, with an annual production capacity of 10,000 tons.