| 摘要 |
PURPOSE:To allow the re-coating process of a hob, with a cutting blade assembled in a main body, by using a steel material with a high annealing temperature of the TiN coating process temperature or more as the material for the member such as a hob main body and a collar. CONSTITUTION:A hob main body 2 and a collar 3 are constituted of a material satisfying the requirements among the steel having an annealing temperature higher than the titanium nitride coating process temperature, e.g., low alloy steel such as Cr, Cr-Mo hot working tool steel. As an example, a material containing C 0.35-0.55%, Si 0.15-0.35%, Mn <=0.50%, P <=0.03%, S <=0.03%, Cr 4.2-4.8%, V 0.18-0.23%, Fe remainder, was used. As a result, this assembly hob was re-ground about 30 times, and the re-coating process was repeated, but there was no change in the mechanical characteristics, because the processing temperature of, e.g., 480 deg.C is lower than the annealing temperature of, e.g., 550 deg.C. |
