| 摘要 |
PROBLEM TO BE SOLVED: To provide sufficient strength without melting after spray coating, form the little distortion of a product and provided the long service life by forming a spray coated film of dispersion strengthening type by high speed flame spray-coating cermet fine powder on uneven processed surfaces formed on the surfaces of respective bar- shaped materials and specifying the surface hardness. SOLUTION: A core section 11a of a bar-shaped material 11 is degreased by using an organic solvent, and the uneven processing is carried out by blasting to form the surface roughness Rz to approximately 70-80μm. Then cermet fine powder is spray coated on the surface of the core section 11a by using a high speed flame spray coater to form a spray coated film 11c. As the cermet fine powder, for example, WC-12Co composite powder of particle size of 10-50μm is preferably used. In that case, one condition of setting the spray coated film 11c at Hv700 or above is indispensable. As the hard and dense spray coated film is formed on the surface by such arrangement, the life is prolonged, and the distortion of a product is scarcely formed, since the melting process of the spray coated film is not required. |
