Recently, Changbao Special Materials Division successfully finished the production and delivery of UNS S32750 super duplex stainless steel tubes for subsea umbilical cables, with a total length of 2,100 meters and a design pressure of 7,500 psi. This marks the completion of Changbao’s first umbilical tube project contract and a major breakthrough for the company in core materials for deep-sea oil and gas extraction.

Subsea umbilical cables are known as the “lifeline” connecting underwater production systems and surface platforms. China’s 15th Five-Year Plan clearly sets goals to advance high-quality development of the marine economy, accelerate self-reliance in high-level science and technology, and raise the localization rate of deep-sea equipment. The successful supply of key materials by Changbao Special Materials Division has taken a solid step toward independent control of the deep-sea equipment industrial chain.

Since the billet extrusion started on April 27, 2026, the team of Changbao Special Materials Division has worked closely around the clock and rigorously controlled every production procedure. After butt welding, the finished straight tubes successfully passed visual inspection, PT and DR (X-ray) testing with excellent weld quality. The urgent delivery was completed within 40 days from extrusion to shipment, fully demonstrating Changbao Special Materials Division’s outstanding capability for emergency supporting services and comprehensive whole-process quality management.

This batch of products adopts the advanced “hot extrusion + cold rolling” process independently developed by Changbao Special Materials Division. The billets are made of UNS S32750 super duplex stainless steel sourced from a leading special steel manufacturer. The finished straight and welded tubes fully comply with customers’ procurement specifications in terms of metallographic structure, mechanical properties and corrosion resistance, with many indicators delivering outstanding performance. Leveraging the high-end production lines, including the imported DANIELI 25MN hot extrusion press from Italy, fully automatic high-speed cold rolling mills, bright annealing furnaces and a CNAS-accredited laboratory, Changbao Special Materials Division have realized full-process digital quality control covering raw material re-inspection, single-piece tracking, non-destructive testing and hydrostatic testing. The products are fully qualified to meet the dual requirements for corrosion resistance and mechanical properties under extreme service conditions in deep sea.

Changbao Special Materials Division is the high-end manufacturing base dedicated to small-diameter precision seamless tubes, with an annual production capacity of 12,000 tons. The products are widely applied in oil&gas exploitation, petrochemical heat exchangers, marine engineering, fine chemicals, semiconductors and other fields. The successful delivery of super duplex stainless steel tubes for umbilical cables marks another major breakthrough for the company in key materials for high-end marine engineering, following the nickel-based alloy OCTG, stainless steel high-pressure boiler tubes and EP tubes. Centering on national strategic demands for deep-sea development, energy industry, semiconductors and precision manufacturing, Changbao Special Materials Division will keep advancing the localization of more high-end products and contribute to the secure, independent  and controllable industrial chain.