Production of special tubes with a variety cross-sectional shapes by bunch drawing and fluid-mandrel drawing

摘要

Recently, special tubes for high efficiency heat exchangers, high functionality electrodes, and super-micro medical needles have attracted attention. In order to produce such special tubes, however, a special processing method or tool is required.In this study, fabrication of special tube by bunch drawing and fluid-mandrel drawing were attempted. And it was revealed that the fabrication of special tubes with a variety of cross-sectional shape is possible, when a bunch of tubes, or a tube of large diameter in which a number of fine tubes are inserted, is drawn.Presumption of cross-sectional shapes after bunch drawing was examined by FE analysis. Cross-sectional shapes and the distribution of Vickers hardness which has relation to equivalent strain were compared between tubes obtained virtually by FE analysis and fabricated actually in this study. It was found that they correspond very well and FE analysis is useful for the presumption of cross-sectional shapes after bunch drawing.