Drill head for sleeve milling gas releasing tube effeciently

The utility model discloses a high-efficiency casing milling air discharging pipe casing taking drilling bit, which consists essentially of a body of a cirque column shape. The utility model is characterized in that the middle and upper parts of the internal wall of the body are fixed with a lifting liner. The body is provided with an internal circulation passage communicated with the internal chamber of the body; the upper part of the body is provided with a channel which is internally welded with a supporting plate which is pave-welded with an ultra-hard cutting piece; the rear side of the supporting plate is fixed with a hard alloy surfacing electrode. The utility model has the advantages of reasonable structure design, convenient and handy application, and avoidance of bit clamping accident and bit loss accident.