A potential new ferritic/martensitic steel for fusion applications

The A-21 steel is an Fe-Cr-Co-Ni-Mo-Ti-C steel that is strengthened by a fi ne distribution of titanium carbide (TIC) precipitates formed by thermomech anical treatment. Transmission electron microscopy of the A-21 reveals a hi gh number density of small TiC particles uniformly distributed in the matri x. Below approximate to 600 degreesC, the strength of A-21 is less than the average value for conventional Cr-Mo or reduced-activation ferritic/marten sitic steels. However, the strength is greater above 600 degreesC. The Char py impact properties of A-21 are comparable to those of the conventional an d reduced-activation steels. Due to the fine TiC particles in the matrix, t he creep-rupture properties of A-21 are superior to those of conventional C r-Mo or reduced-activation Cr-W steels. Although the composition of the A-2 1 is not applicable for fusion because of the cobalt, the innovative produc tion process may offer a route to an improved steel for fusion. (C) 2000 El sevier Science B.V. All rights reserved.