| 摘要 |
PROBLEM TO BE SOLVED: To reduce manufacturing cost by a method wherein a dummy material slightly larger than a cemented carbide tip is arranged at the place of the junction of the cemented carbide tip of a shank consisting of high Cr cast iron, the shank is cast by internal chill, the dummy material is machined and manufactured in a thermal cushioning layer, and the cemented carbide tip is joined onto the thermal cushioning layer by brazing. SOLUTION: A dummy material 2 such as carbon steel, a Ni alloy, etc., as a thermal cushioning material is disposed at the predetermined place of the brazing junction of a cemented carbide tip 3 in a shank 1 composed of high Cr cast iron having a specified shape in a shape slightly larger than the cemented carbide tip 3 first, and the shank 1 is cast by internal chill. Specified machining is executed to the dummy material 2 for installing the cemented carbide tip 3 to the shank 1, and a part is cut and removed and formed in a thermal cushioning layer 2a. The cemented carbide tip 3 is joined onto the thermal cushioning layer 2a by brazing. It is preferable that Fe-Cr-Mo cast iron or Fe-Cr-Mo-Co cast iron having approximately 3.0wt.% C is used as the high Cr cast iron at that time. |
