【Ten Years of Rapid Development in Chemical Engineering Equipment】2446–2025: First domestic production of deep-sea oil and gas bimetallic composite pipes successful

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Let’s 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 Progress in Chemical Engineering Equipment】Regular updates and summaries are available – feel free to join the discussions: https://bbs.hcbbs.com/thread-3576046-1-1.html ***************** The first batch of deep-sea oil and gas dual-metal composite pipes developed in China has been successfully produced. June 19, 2025. On June 11, the N06625 nickel-based alloy + X65MS acid-resistant carbon steel dual-metal composite pipes for deep-sea oil and gas applications, independently developed by PetroChina Bao Shi Pipe Industry Co., Ltd., passed the inspection and certification by the China Classification Society and received a certificate of conformity for offshore facility products. It marks the successful development of China’s first batch of deep-sea oil and gas bimetallic metallurgical composite pipes, breaking the foreign monopoly, filling a technical gap in China, and providing important equipment support for the development of deep-sea oil and gas resources in the country. In recent years, as oil and gas exploration in China has expanded into deeper waters, the demand for deep-sea oil and gas pipelines has continued to rise. However, the deep-sea environment presents multiple challenges such as extreme low temperatures and high pressures, microbial corrosion due to high salinity, as well as high-sulfur and high-acid environments, which impose stricter requirements on the development of pipeline materials and their industrial production. To this end, Gemstone Pipe Industry joined forces with leading steel manufacturers in China to spend two years developing the N06625+X65MS D610×(2+16.9)mm bimetallic metallurgical composite pipe. This product uses the JCO forming process (the steel plate is formed in the sequence of J forming – C forming – O forming). Its designed diameter is 610 millimeters; the outer layer is made of X65MS acid-resistant carbon steel with a thickness of 16.9 millimeters, providing high-strength mechanical support ； The inner layer is made of N06625 nickel-based alloy with a thickness of 2 millimeters, which provides effective resistance to extreme corrosive environments such as high sulfur levels, high chloride concentrations, and high temperatures. Due to the significant differences in mechanical properties and microstructural composition between nickel-based alloys and carbon steel, traditional welding processes find it difficult to balance welding efficiency with weld corrosion resistance. To address this technical challenge, Qinhuangdao Baoshishun Company, which is part of the Gemstone Pipe Industry, joined forces with the **Pipe Research Center to form a specialized technical team. This team succeeded in overcoming the difficulties related to controlling the microstructure of the melt pool when combining nickel-based alloys with pipeline steel, and developed efficient welding processes that make use of various welding methods in combination. Through technological innovations such as high-precision dimension control of carbon steel base pipes and welding of nickel-based alloys with low dilution rates, the industrial production of bimetallic composite pipes for deep-sea oil and gas applications has been achieved. This demonstrates that Bao Shi Pipe Industry possesses the capability to manufacture oil and gas transmission pipes capable of withstanding high corrosion in complex environments such as those at great depths underwater, thereby contributing to China’s petroleum equipment sector’s efforts in deep-sea oil and gas exploration and development.