| 摘要 |
PURPOSE:To prevent a tool from corroding and a chuck from slipping by forming a roundish rough surface on the lip part of a seaming chuck and a chemical Ni base plating and a WC base surface hardening treatment are applied to the surface in due order. CONSTITUTION:A surface roughening work resulting in a 5-20mum roughness by horning or the like is applied to the grinded lip part of a seaming chuck 4 being easily subject to wear. The rough surface is formed into a roundish surface on the whole by a barrel polishing work or a lapping work and the surface roughness should be about a 3-15mum. After Ni phosphide or Ni boride, electroless Ni plating layer 17 is formed on the above base surface, a WC layer 18 is precipitated and covers the surface by a vapor phase reaction of a mixture of WF6, hydrocarbon, and H2 a prescribed temp. in a sealed furnace. In this method, a hardness difference between both plating layers 17 and 18 is reduced, so that separation of the WC layer and corrosion of the chuck 4 are prevented.
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