| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve such problems that it is difficult to uniformly cool all of hard metal tips though a drilling bit for cutting a converter sleeve brick is generally cooled by ejecting a cooling water of 20 l/min with a high-pressure air of 0.5-1.0 MPa, and thus the tip is actually cooled by an evaporative latent heat generated when the cooling water evaporates, and further, the hard metal tip is apt to be susceptible to high-temperature oxidation since the tip serving as a cutting blade consists mainly of WC. <P>SOLUTION: The solution includes: cooling the surface of drilling portion by providing a cooling water-filling chamber inside the drilling bit; improving a cooling efficiency by brazing a copper rod to the lower part of the tip to protrude the copper rod in the cooling water-filling chamber; and improving the cooling efficiency by providing a through-hole to the tip and by providing a water-passage hole to a sleeve or the tip. <P>COPYRIGHT: (C)2012,JPO&INPIT |
