Tube rolling method and apparatus
AssigneeSumitomo Metal Industries, Ltd.
InventorsKouichi Kuroda, Youichi Imamura, Kazuyuki Nakasuji, Chihiro Hayashi
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Abstract
According to the rolling method and the apparatus to be used for its execution of the invention, by rolling a tube to be rolled by using four rolls possessing roll grooves for forming a caliber in a shape of having a relief portion, cold reducing or cold stretch reducing is done continuously without causing wall thickness deviation, and by sizing the rolled tube material by a die disposed at the exit side, the dimensional precision and yield of rolled tubes may be enhanced by a small number of stands.
Claims28
A tube rolling method, comprising the steps of:
- disposing a plurality of stands along a longitudinal pass line, each stand having four rolls in tandem, wherein the rolls of a preceding stand and of a succeeding stand differ in phase by about 45 degrees relative to the pass line formed by the stands, and the rolls include roll grooves for forming a nearly circular caliber;
- and
- continuously passing a tube in a cold state through said plurality of stands such that an outer diameter of the tube is rolled and reduced;
- wherein the roll grooves satisfy the following conditions:
- a.sub.i >b.sub.i
- a.sub.i <b.sub.i-1
- where a.sub.i is a caliber radius of a roll groove edge of an i-th stand;
- b.sub.i is a caliber radius of a roll groove center of the i-th stand;
- and
- b.sub.i-1 is a caliber radius of a roll groove center of an i-1-th stand.
A tube producing apparatus, comprising:
- a plurality of stands, arranged along a longitudinal pass line, for reducing an outer diameter of a tube passing through the stands in a cold state;
- wherein each stand includes four rolls in tandem, the rolls of a preceding stand and of a succeeding stand differing in phase by about 45 degrees relative to the pass line formed by the stands, the rolls having roll grooves which form a nearly circular caliber, the roll grooves satisfying the following conditions:
- a.sub.i>
- b.sub.i ;
- and
- a.sub.i<
- b.sub.i-1
- where a.sub.i is a caliber radius of a roll groove edge of an i-th stand;
- b.sub.i is a caliber radius of a roll groove center of the i-th stand;
- and
- b.sub.i-1 is a caliber radius of a roll groove center of an i-1-th stand.
Dependencies are inferred from the claim text.