| 摘要 |
<p>IMPROVED METHOD FOR THE SURFACE HARDENING OF DRILL ROD COUPLINGS, AND THE RODS THUS OBTAINED A method for surface-hardening a facial band of the female coupling of a steel drill rod, said band lying between the threaded zone of the coupling and the tapered zone which joins the coupling to the cylindrical rod body, comprising cleaning said band by brushing and/or sandblasting, inductively preheating the band and finally raising a surface film layer of said band to austenitizing temperature by means of a laser beam.</p> |
