CPC B21D 22/16 (2013.01) [B21K 1/22 (2013.01); F01L 3/14 (2013.01); F01L 3/20 (2013.01); F01L 2303/00 (2020.05); F16K 1/36 (2013.01); F16K 49/007 (2013.01)] | 13 Claims |
1. A method for producing a valve body of a hollow valve, comprising:
providing a preform comprising a valve head at a closed end of the preform and a tubular wall, which surrounds a cylindrical cavity extending to an opposite open end of the preform;
extending a flow forming mandrel into the cylindrical cavity through the open end and externally supporting the closed end with a tailstock such that the valve head is interposed between the tailstock on the outside of the valve head and the mandrel on an inside of the valve head,
flow forming the tubular wall in order to increase a length of the tubular wall,
wherein a plurality of flow forming rollers are used during the flow forming which are radially and axially offset to one another during the flow forming,
wherein the flow forming mandrel rotates together with the preform and the tailstock during the flow forming.
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