TUBULAR STRUCTURAL MATERIAL Russian patent published in 1999 - IPC

FIELD: manufacture of articles from metal, for example, by rolling, extrusion or by methods of powder metallurgy; applicable in construction, machine building, etc. SUBSTANCE: tubular structural material has boundaries of external and internal sides in its cross-section. On boundary of external and/or internal side at least one part of boundary line of section is made in the form of fragment of oblique conical section of right circular cone. In this case, design provides for variation of thickness of tubular structural material in shape-forming apparatus by using fragments of oblique conical section of right circular cone. Invention provides for improvement of adaptability to manufacture of articles and reduction of specific consumption of materials due to use of combination of fragments of oblique conical sections of right circular cone passing in each other and do not prove beyond the parameters prognosticated before shape-forming operations. EFFECT: higher efficiency. 18 cl, 13 dwg