Increasing of drill-pipe endurance capability, based on modeling and controlling of thread burnishing parameters

The correlations between constructive and technological process parameters of drill-pipe tapered surface thread burnishing (configuration of hardenable rolling element, load rate, root radius), magnitude of residual stress and stress distribution on the thread surface were interrelated. They are based upon the set of discovered mathematical models and experimental research of stressed-deformed state and fatigue tests.
Materials and methods
Test reports are based upon the theory of continuous media deformation, mechanical engineering, dynamics of vehicles and machinery, theoretical mechanics, modeling techniques of stressed-deformed state, the theory of surface plastic deformation. The results of test reports were recorded, using video, certified modern instruments and measurement tools. Visualization and elaboration of test results were analyzed, using interdisciplinary engineering software suite by means of high-efficiency computer complex and software suite ANSYS, ABAQUS, and application software PKNM Deep Roll Thread v 1.0 (“Running thread roller PKNM version 1.0”).
Results
The correlations between process of hardening and quality parameters of the surface layer; the methodology for the static and dynamic mathematical modelingand practical application of technological process, concerning with thread burnishing of hard-to-profile tapered threads with pressure rollers - the parameters were displayed as the result of laboratory tests.
Сonclusions
Application of thread burnishing made it possible to reduce the pipe destruction by a factor of 3; to obtain the significant economic benefit by means of their durability increasing and to increase the competitiveness of drill pipes manufacturing in Russia.