1985 Volume 71 Issue 6 Pages 735-742
There is a limit to grain refinement of high-speed tool steel by usual recrystallization process at the austenite region even after working with a large reduction.
In a series of our experiments, however, it was shown that in steel specimens processed through preforming and then solution treatment, the grain size after recrystallization was extremely refined. Tests carried out in a range of commercial high-speed tool steels quantitatively clarified the effect of preform reduction, solution temperature, reduction for recrystallization and annealing temperature on the final grain sizes.
Furthermore, it was shown that high-speed tool steel with fine grain sizes was possible to become superplastic and its total elongation exceeded 300% over a suitable range of temperatures and strain rates.