| 摘要 |
<p>The present invention relates to the field of insert bits (10) for use with powered screwdrivers. The formed bits (10) may be treated to have a desired microstructure by either an austempering process or by the three step heating, quenching, tempering process. The bits (10) may also be electro-polished. Austempering provides for improved function and increased fatigue life and electro-polishing provides for improved function and increased fatigue life and torque capacity. The bits (10) may have reduced diameter midportions (30), particularly for use with impact drivers.</p> |
