METHOD OF PRODUCING ULTRA-FINE-GRAIN BILLETS FROM METALS AND ALLOYS Russian patent published in 2010 - IPC B21J5/06 C22F1/18 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming designed to produce ultra-fine-grain structure increasing physical and mechanical properties of parts and can be used in machine building, aircraft engineering and medicine. Method comprises intensive plastic deformation by multiple all-around forging. At every forging stage, strain direction is successively changes along three axes of coordinates. Forging is started in billet material forging temperature range. Then temperature is decreased after every or several deformation stages to temperature below recrystallisation threshold. Forging is performed inside mold cavity in plain-strain condition. Biller size is reduced in direction of first axis of coordinates that complies with strain force direction. Billet size is increased in direction of second axis of coordinates on the biller free side. Billet size is maintained in direction of third axis of coordinates on billet fixed side. Billet size in direction of first axis of coordinates does not exceed that in direction of third axis of coordinates. Machining is made in several cycles to produced accumulated strain degree making at least 3.

EFFECT: improved physical and mechanical properties, higher process efficiency.

4 cl, 1 ex, 2 dwg