| 摘要 |
FIELD: mining industry. ^ SUBSTANCE: connection and element include at least one mostly cylindrical outer thread and respectively mostly cylindrical inner thread. Outer thread is made at pipe portion, making up a solid whole with component of drilling bars. Threads include side edges and recesses placed between them. Recesses of cylindrical outer thread are placed mostly at a distance from appropriate vertexes of cylindrical inner thread, one of portions with decreased cross-section is partially composed of layer of material with higher electrode potential, than that of steel, made of nickel, chrome, tin, cobalt, titan or alloys thereof. ^ EFFECT: higher efficiency. ^ 2 cl, 6 dwg, 1 ex |
