| 摘要 |
<p>1,162,338. Billet piercing ; extruding. HENRY WIGGIN & CO. Ltd. 25 March, 1968 [7 April, 1967], No. 14240/68. Headings B3H and B3P. [Also in Division C7] A mandrel 40 for an extrusion press comprises a central tensile bar 42 of high yield strength maraging steel surrounded by a ductile casing 41 located by a retainer 43 on the forward end of the bar. The retainer may be screwed on the bar or formed integral therewith, Fig. 2 (not shown). The rear end of the bar is threaded at 52 for securing to a mandrel holder (51), Fig. 5 (not shown). Coolant is circulated through a pipe 46 to a bore 45 in the bar 42 and is returned through radial ports 48, longitudinal grooves 49 and radial ports 50. In other embodiments the central bar is solid. A billet piercing point (34), Fig. 3 (not shown), may be used on the end of the retainer. Specific compositions are given for the metals used in the bar 42 and in the casing 41 and examples are given for extruding billets of nickel-chromiumiron alloy of given composition. The bar may be heat treated. .</p> |
