PURPOSE: To prevent seizure between a bearing part and a work and to work a work stock excellent in surface smoothness by forming a die body constituting a bearing part from cemented carbide material and adjusting the surface roughness of the bearing part in a specified extent.
CONSTITUTION: The die body 2 which is formed out of the bearing part 2a and a relief part 2b and made of cemented carbide material is shrunk and fitted integrally to a recessed part 4 for insertion in the middle of a die case 3. When a work stock passes the bearing part 2a at the initial stage of working, very fine dents 11 formed on the surface are filled by adjusting the surface roughness of th bearing part 2a to 5-30S with working material 12 and a thin film of working material 12 is easily generated. When the bearing part 2a is covered uniformly with a film of the same composition as that of the working material 12, the affinity between the bearing part 2a and the working material is improved, the seizure at the time of working is relieved and damages generated on the working surface are reduced.
OKUBO KUNIO
SAKAIRI TOKIO
SUDO MASAMI
