Yangzhou Chengde Heavy Industry applies for a patent for a sizing production method for large-diameter seamless steel pipes that reduces the number of heating cycles required in steel pipe production

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Yangzhou Chengde Heavy Industry has applied for a patent for a production method for sizing large-diameter seamless steel pipes, aimed at reducing the number of heating cycles required in their production. According to information from the Intellectual Property Office, dated August 18, 2025, Yangzhou Chengde Heavy Industry Co., Ltd. has filed a patent titled “Production Method for Sizing Large-Diameter Seamless Steel Pipes with Diameters of 1200–1700 mm”; the publication number is CN120479943A, and the application was submitted in June 2025. The patent abstract indicates that this invention discloses a production method for sizing large-diameter seamless steel pipes with a diameter of 1200–1700 mm, and it falls within the field of seamless steel pipe manufacturing in the metallurgical industry. The present invention involves piercing large continuous casting billets, cross-rolling for diameter expansion, and subsequently reheating them directly in a reheating furnace. The reheating is carried out online; after that, sizing is performed. The entire process requires only two heating stages, thereby reducing the number of heating operations in steel pipe production. The finished pipes undergo internal and external grinding and polishing, resulting in a high yield rate. A single blooming mill and one set of rolls are sufficient for sizing large-diameter steel pipes. Moreover, this setup allows for a wide range of outer diameters to be produced using the same rolls, thus minimizing the need for additional molds and reducing related investment costs. By utilizing the reciprocating rolling of the primary rolling mill, as well as the movement and turning of the push-pull bed, this invention enables uniform deformation of each surface, allowing the two rollers to achieve a larger pitch between steel tubes. Compared with existing traditional production processes for sizing and controlling the outer diameter of steel pipes, this invention requires fewer production steps, has a simpler process, higher production efficiency, lower investment in molds, and thus significantly reduced production costs.