| 摘要 |
PURPOSE:To obtain highly accurate close-contacting degree and airtight joining condition throughout all the butting surfaces between both end surfaces of a plate-shaped blank material, by using a copper blank material of special Vickers hardness in forming work to round the material. CONSTITUTION:A plate-shaped blank material having a quality range 70-95 Vickers hardness is used in round-forming said material made of copper into the cylindrical primary workpiece. After that, an ironing (draw)-forming is performed to stably obtain the secondary workpiece having perfectly gapless joining surfaces between both end surfaces of the material from the inside to outside and throughout all the surfaces in the axial direction. Further, by this method, a product having sufficiently satisfied quality, in the roundness and in the wall thickness deviation around the circumference, is obtained. |
