| 摘要 |
A thread-cutting screw ( 1 ) serves for being screwed into the bore-hole wall ( 1 a) of a bore-hole ( 1 b). It comprises a substantially cylindrical core ( 2 ) of metal which has a central longitudinal axis ( 4 ), a thread ( 5 ) forming one piece with the core ( 2 ), and at least one cutting element ( 6, 7 ), disposed within the thread ( 5 ), for cutting engagement with the bore-hole wall. The core ( 2 ) consists of a metal of a carbon content between 0 and 0.5 percent by weight. The at least one cutting element ( 6, 7 ) is fixedly connected with the core ( 2 ), constituting a welded structure of a metal with a carbon content greater than 0.8 percent by weight. Being safely connected to the core ( 2 ), the cutting elements ( 6, 7 ) offer efficient cutting operation, with any risk of brittle fracture of the screw ( 1 ) being precluded. |
