| 摘要 |
The present invention relates to a thread joint and a drill element for percussive drilling wherein flushing water is used, comprising at least one substantially cylindrical external thread as well as a substantially cylindrical internal thread (12). The external thread is provided on a spigot (13) intended to constitute an integral part of a first drill string component. The threads (12) comprise thread flanks (16, 17; 18, 19) and thread roots (20; 21) provided between the flanks. The thread roots (20) of the cylindrical external thread is provided substantially distant from associated crests (22) of the cylindrical internal thread (12). By coating the thread roots (20) of the cylindrical external thread with at least one layer of a material of higher electrode potential than the underlying steel such as nickel, chromium, copper, tin, cobalt, titanium or alloys thereof an increased life length for the threaded connection is obtained. |
