| 摘要 |
PURPOSE:To give superplasticity by cold-working and heating a material which is heated to the A3 point or above and cooled rapidly. CONSTITUTION:As steel, hypo-eutectoid steel containing alloying elements of 1 or >=2 kinds among 0.05-2wt% Nb, 0.1-2wt% V, and 0.05-1wt% Al and having an improved grain growth-controlling effect is used. The hypo-eutectoid steel is heated to a temp. of the A3 point or above and cooled rapidly, which is subjected to cold working and then to heating to form a fine two-phase structure. |
