improved process for hardening surface of joints of drilling rods and poles so obtained.

摘要

A method for surface-hardening a facial band (F) of the female coupling (6) of a steel drill rod, said band lying between the threaded zone (7) of the coupling and the tapered zone (5) which joins the coupling to the cylindrical rod body (1) comprises 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. IMAGE