【Ten Years of Rapid Development in Chemical Engineering Equipment】From 2023 to 2025, BEIJIANG HEAVY INDUSTRY obtained a patent for the extrusion manufacturing method of large-diameter seamless pipes made of S32750 duplex stainless steel

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Give praise and encouragement to the achievements made in China’s chemical engineering technology and equipment; your participation in discussions is the greatest encouragement. **********************【Ten Years of Great Development in Chemical Engineering Equipment】Continuous updates and summaries are available; feel free to join the discussions at https://bbs.hcbbs.com/thread-3576046-1-1.html ***************** S32750 super duplex stainless steel is a material with excellent corrosion resistance and high strength, and it is widely used in the chemical industry, offshore platforms, the papermaking industry, and other applications where high corrosion resistance and mechanical properties are essential. According to information from the Intellectual Property Office as of April 30, 2025, Inner Mongolia Northern Heavy Industry Group Co., Ltd. has filed a patent application titled “Method for Extruding Large-Diameter Seamless Steel Tubes Made of S32750 Duplex Stainless Steel”, with the publication number CN119870200A; the application was submitted in December 2024. The patent abstract indicates that this invention discloses an extrusion manufacturing method for large-diameter seamless steel tubes made of S32750 duplex stainless steel, which includes: electric furnace smelting of S32750 duplex stainless steel, secondary refining, vacuum degassing, and casting of steel ingots in molds ； After demolding, the steel ingot is placed in a heating furnace for heating and holding at a constant temperature ； After the steel ingot is coated with glass powder lubricant, a hollow billet is produced through closed upsetting and reverse extrusion punching; the hollow billet is then air-cooled or water-cooled to room temperature ； After mechanical processing of the surface of the hollow blank, it is placed in a heating furnace for heating and holding at a constant temperature; after spraying a glass powder lubricant, the hollow blank is extruded to obtain a rough steel pipe blank ； Immediately after extrusion, the steel tube billet is placed in water for rapid cooling; subsequent solution treatment and mechanical processing are carried out to achieve the desired dimensions, resulting in large-diameter seamless stainless steel tubes made of S32750 duplex stainless steel. The present invention solves the problems of low low-temperature impact toughness at -47°C and surface cracking in large-diameter seamless steel pipes made of S32750 duplex stainless steel.