A drill crown (1) used for drilling purposes, especially for rotary percussion
drilling of a mouth of a blast furnace. The drill crown (1) consists of
a drilling head (4) provided with a plurality of hard material or hard metal
inserts (6) and a base body (2) for connection to a drive element
etc. in order to drive or impinge upon said drill crown. The hard material or hard
metal inserts (6) are received in bores or openings (5) of the drill
head (4). According to the invention, at least one hard material or hard
metal insert (6) is provided with an at least partially curved or domed
surface contour (11) on the end which is received in the drill head (4).
Said contour cooperates with a complementary domed or curved surface of the drill
head (4) and/or base body (2), whereby the percussive energy required
for appropriate drilling power is transmitted in a reliable manner, even when the
hard material or hard metal insert (6) is slackened.
