| 摘要 |
<p>A threading tap comprises a cylindrical shaft and a threading portion (2). At least the threading portion consists of a compound material comprising a core of high speed steel or tool steel and a cover of "Coronite" (registered trademark), i.e., a hard material with 30 to 70% by volume of submicronic hard materials in the form of carbides, nitrides and/or carbonitrides of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and/or W in a metallic matrix based on Fe, Co and/or Ni. The chip surfaces (13) adjacent to the cutting edges (12) of the cutting threads (9) have a negative rake angle ( alpha ). The threading tap has proven to be excellent at the threading of titanium-based alloys. <IMAGE></p> |
