On September 19, YXTG Special Steel (002756.SZ) issued an announcement saying that the company and Wujin Stainless and the State Electricity Investment Research Institute jointly developed the “manufacturing technology for large-caliber super austenitic stainless steel seamless pipes in seawater systems of nuclear power plants.” “Successfully passed the scientific and technological achievements appraisal organized by China Machinery Industry Federation to fill the gaps at home and abroad.
According to the announcement, from the current operating experience of domestic nuclear power plants, the corrosion and erosion of seawater systems are common problems in coastal power plants. Among them, seawater pipelines are the main equipment for transporting seawater. If they are in contact with seawater for a long time, local pitting and perforation, crevice corrosion and stress corrosion cracking are more likely to occur.
Therefore, China ’s third-generation nuclear power technology AP1000 and CAP1400 nuclear power plants use N08367 super austenitic stainless steel seamless pipes in the design of seawater corrosion-resistant pipelines to improve corrosion resistance. The maximum outer diameter of the CAP1400 nuclear power plant seawater system is 711mm. . However, due to reasons such as the performance of basic pipe-making materials failing to meet requirements, there is no precedent for successful development of large-caliber N08367 super austenitic stainless steel seamless pipes worldwide.
YXTG Special Steel said that the size, chemical composition, mechanical properties, corrosion resistance, non-destructive testing and hydrostatic test results of the large-caliber super austenite seamless pipes developed in this achievement meet the standards of ASTM B690 and related technologies Claim. The technical features and innovations are as follows:
(1) Research and design a set of N08367 super austenitic stainless steel high-purity smelting and nitrogen control process technology to obtain N08367 tube billets with better quality.
(2) A large-caliber thin-walled thin-walled N08367 super austenitic stainless steel seamless pipe perforating process has been designed and developed to realize a single perforation.
(3) Research and design a set of manufacturing processes for drawing, rolling and solid solution.
Applying the above key manufacturing technologies, N08367 super austenitic stainless steel large-diameter seamless pipe samples were successfully developed, reaching the international advanced level.
According to the announcement of the results, the passing of expert appraisal marked the successful development of the large-size base material of YXTG Special Steel N08367 super austenitic stainless steel, which strengthened the company’s research and development capabilities. In the AP1000 and CAP1400 nuclear power plants, N08367 super austenitic stainless steel large-diameter seamless pipes are used as pipelines in the seawater system. With the advancement of the construction of AP1000 and CAP1400 nuclear power plants, Yongxing Special Steel will further adjust the product structure.
YXTG Special Steel claims that N08367 super austenitic stainless steel has excellent comprehensive properties and can be widely used in seawater systems of other reactor nuclear power plants. With the development of offshore oil platforms and offshore floating reactors, the requirements for seawater corrosion-resistant materials have increased. The higher and higher, the demand is also increasing, N08367 super austenitic stainless steel material is expected to be used in the above related fields, the market space in the future is huge.