CURRENT PROGRESS IN ADVANCED HIGH CR FERRITIC STEELS FOR HIGH-TEMPERATURE APPLICATIONS

The article presents recent developments and future trends in high Cr ferritic heat resistant steels. Research programs are underway worldwide to improve the performance of 8 to 13% Cr ferritic steels for high temperature applications of up to 650-degrees-C. We developed the super 12% Cr heat resistant steel called TAF steel in 1956. The creep rupture strength of TAF steel is two or three times higher than those of H46 and AISI422 at 600 and 650-degrees-C. Our research in this area was well ahead of work being conducted in other countries. Recently the author succeeded in developing TR1100, TR1200, TB9 and TB12 with excellent high temperature properties and room temperature toughness through the improvement of TAF steel. In the near future, these new steels will be applied to turbine rotors, blades, and boiler tubes for advanced supercritical power plants, to fuel cladding, wrapper and steam generator tubing for fast breeder reactors, and to first wall materials for conceptual fusion reactors. These steels are a key to making these plants and reactors practical.