METHOD OF RESTORATION OF SUCKER RODS Russian patent published in 2006 - IPC C21D8/00 C21D7/12 

FIELD: gas-and-oil producing industry; methods of restoration of sucker rods after their usage in mechanized deep-well oil pumping operations.

SUBSTANCE: the invention is pertaining to the field of gas-and-oil producing industry, in particular, to the methods of restoration of sucker rods after their usage in mechanized deep-well oil pumping operations. For relieving fatigue stresses of the deep-well oil sucker rods after their operation term they are subjected to the thermal treatment at the temperatures of 200-650°C during 15-30 minutes. The thermal treatment consists of normalization, improvement or tempering depending on the material of the deep-well oil sucker rods subject to restoration. After the stress-relief treatment the deep-well oil sucker rods are subjected to the straightening by tension in their hot state with the help of utilization of the temperature of the stress-relief treatment or a separate heating up to the yield stress of the article with the force up to 18 ton\s and with the rate of deformation up to 1.5 m/minute. After cooling down the deep-well oil sucker rods are subjected to the shot blasting for reaching the necessary straightness and to the stress relief arising at the straightening. After the straightening the sucker rods are subjected to the shot blasting for scaling off, localizations of microcracks and for increasing fatigue strengths due to decrease of the stress concentration on the surface of the superficial work hardening. The technical result of the invention is the increased reliability and the service life of the of deep-well oil sucker rods.

EFFECT: the invention ensures the increased reliability and the service life of the of deep-well oil sucker rods.

2 cl