METHOD FOR OBTAINING NANOCRYSTALLINE STRUCTURE OF MATERIAL IN PIPE WORKPIECES AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2010 - IPC B82B3/00 B21C37/29 B21D9/00 

FIELD: metallurgy.

SUBSTANCE: group of inventions refers to plastic metal working and is intended for obtaining nanocrystalline metal structure in pipe workpieces, schemes of stress and strain state of deformable material. Workpiece cavity is filled with filler, edges are sunk with axial punches and middle zone of workpiece is shifted in the direction perpendicular to its axis at creation of pressure, during the shift, in filler, which is kept by constant control of the filler amount, and shift speed is chosen depending on sinking speed of edges and also kept constant. At the end of odd workpiece deformation step there stopped is sinking of its edges by keeping its cavity tightness, and at even step there performed is shift of middle part of workpiece in the direction opposite to the previous one till the workpiece has initial straight-line state. At that, shift speed of middle zone of workpiece is provided depending on movement speed of axial punches. Workpiece is rotated through standard angle relative to its axis and odd step of its deformation is implemented, or direction of shift of middle part of workpieces is kept at odd and even deformation steps. Device includes split die consisting of upper and lower semi-dies and having central insert consisting of pressure-bearing and support semi-inserts, punches of axial compression of pipe workpiece. In die channels there arranged are pins the section of which has the shape corresponding to the shape of workpiece section, which interact with their edges on one side to workpiece surface, and on the other side - with stocks of hydraulic cylinders the axes of which are perpendicular to pin axes. At that, pins and hydraulic cylinders are arranged in pairs in upper and lower semi-dies.

EFFECT: increasing efficiency and ensuring the quality.

4 cl, 14 dwg