| 摘要 |
An annular workpiece (114), in blank form, is snugly received within a central opening portion of an annular die member (78) having a radially inwardly directed die face. The two ends of the workpiece make sealing contact with radially inwardly sloping outer sidewall portions (118) of annular seal grooves (116) formed in support members (36, 54) for the two ends of the workpiece (114). The support members (36, 54) and the annular die member (78) are heated, by the use of induction heating apparatus (38, 42, 80, 100, 102, 52, 54), while a molten metal is pressure fed into the interior of the workpiece. The molten metal is pressurized while it is within the workpiece and it functions to both heat the workpiece and press it radially outwardly into forming contact with the die face. As the workpiece is being stretched in this manner and is taking the shape of the die face, the two end support members (36, 54) are being moved relatively together. As such members (36, 54) move, the end portions of the workpiece are turned inwardly by, and slide relatively along, the radially inwardly sloping outer surfaces (118) of the seal grooves (116). The pressure within the workpiece acts on inwardly turning lips being formed at the ends of the workpiece, pressing them radially outwardly into tight sealing contact with the sloping surfaces (118) of the grooves (116). Induction heating (64, 124) is used for heating the molten metal while it is within a storage vessel (64) and also while it is inside the workpiece (38, 42).
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