METHOD OF FABRICATION OF PUMP BARS Russian patent published in 2009 - IPC E21B17/01 C21D8/00 B21C37/00 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil production equipment, particularly to methods of fabrication of pump bars. The method of fabrication of pump bars consists in heating ends of stock of round bar for punching heads of the pump bar, in punching heads of the pump bar, in heat treatment of the pump bar and in following shaping of the body of the pump bar in a hot state, in thread rolling of the pump bar, in rolling surface of a behind-thread groove and in strengthening a surface layer of the body of the pump bar. Strengthening of a surface layer of the body of the pump bar is carried out with cold-work hardening in a preliminary stressed state, which corresponds to a combination of overload reinforcement with cold-work hardening. Also the stock is stressed with load of the same direction, that a working load affecting the bar at operation.

EFFECT: increased operation life of bars due to raised fatigue-corrosion hardness of bar material.