Abstract: Themajor forms of the invalidation of the mainbody of the pneumatic percussive drill bit for geophysical research: the fatigue breakdown of the transverse plane , the plastic distortion and the pressed flake of the spline, the abrasion of themainbody of the drillbit. Themainbody invalidation did greatharm by decreasing the energy transfer efficiency and leading to the desquamation of the teeth of the drillbit. The superhigh-strength-and
-low-carbon steel22SMi nNi2CrMoA was chosen for thematerial of themainbody. Based on the experiment, the best heat treatment of the 22SMi nNi2CrMoA was ultimately confirmed as fol lows: forging blank, homogenizing, annealing, quenching at 890℃and Tempering at300℃. The best depth of the quenchhardened rangewas between 1. 8 - 2. 0mm. Heat treated, the
strength, hardness and anti-impact flexibility of the material 22SMi nNi2CrMoA was higher than dom and close to the overseas, or even better.

Key words: geophysical dril, l materia, l heat treatment, experimental research