2021 Atomic Energy Organization of Iran (AEOI) video and International Atomic Energy Agency (IAEA) reporting have revealed Iran’s renewed interest in metal bellows in its advanced centrifuges. In the case of the IR-6 centrifuge, this interest may represent the development of a design change, since earlier Iran declared this centrifuge as having carbon fiber bellows. The most logical choice for the metal in these bellows, based on characteristics of gas centrifuges, is maraging steel.
Maraging steel bellows are well known to be used in the IR-2m centrifuge, but Iran has not made any of these centrifuges in years, leading to speculation that the bottleneck was the maraging steel.
Another indication that Iran is intensifying its interest in maraging steel in its centrifuge program is an early 2021 announcement of a translation of a Western textbook on maraging steel. Two researchers affiliated with Iran’s Shahid Beheshti University translated a 2009 book about maraging steel, titled “Maraging Steels: Microstructure Modeling, Properties and Applications.” The description of the book, part of the 2021 announcement on the website of Shahid Beheshti University, emphasizes properties that are examined, including “corrosion and mechanical properties,” especially for use of maraging steel in the nuclear industry. It further highlights that the nuclear industry “requires more sensitivity and precision in the manufacture of parts used in this industry.” Another part directly references the need to improve certain parts in the nuclear industry, possibly a direct reference to maraging steel centrifuge components: “The need to improve the quality of various parts in order to increase the efficiency of equipment, access to optimal production processes and reduce production costs, multiplies the importance of material design and its manufacturing process.”