| 摘要 |
PURPOSE:To obtain the title cylindrical blank having fine crystal grains and suitable to spinning by hot-extruding a maraging billet, cold-drawing the material at a specified draft, and then applying solution treatment. CONSTITUTION:A maraging billet of Ni-Co-Mo-Ti, etc., is hot-extruded, and then air-cooled to room temp. The number of the crystal grain size is then measured. The measured value is substituted for the G.S in the inequality to obtain the draft (Rd), cold drawing is carried out at the draft, and solution treatment is then applied. The Cold drawing consists of spreading, reduction, and madrel drawing. By this method, the cylindrical blank having <=about No.7.5 crystal grain size and highly suitable to spinning can be obtained. Accordingly, the working yield is enhanced, the product precision is improved, a long- sized cylindrical blank can be produced, and productivity is also ameliorated. |
