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US 4,470,282 AGranted
Method of piercing in seamless tube manufacturing
AssigneeSumitomo Kinzoku Kogyo Kabushiki Gaisha
InventorChihiro Hayashi
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AssigneeSumitomo Kinzoku Kogyo Kabushiki Gaisha
InventorChihiro Hayashi
Estimating the term…
The invention relates to a method of rotary piercing in seamless tube manufacturing under a rotary piercing process, such as Mannesmann mandrel mill process. Rotary piercing operation is carried out by employing a rotary piercing mill having a pair of cone-shaped main rolls adapted to cooperate with a plug for rotary piercing and disc rolls disposed in opposed relation between the pair of main rolls and adapted to press hollow shell on the surface thereof. In this method of rotary piercing, the main rolls have feed and cross angles designed to meet certain conditions individually and in combination. The method makes it possible to carry out rotary piercing of less hot workable and/or extremely hard-to-work materials, that is, high-alloy steel billets, without surface torsional deformation and circumferential shear deformation. Thus, it is possible to manufacture high quality tubes of high-alloy steels free from outside seams and inside bore defects.
A method of rotary piercing in seamless tube manufacturing wherein a heated billet is fed into the roll gap between opposed rolls and subjected, while being moved forward in rotation on its axis and in the axial direction, to center rotary piercing by a plug disposed between the rolls until it is turned into a hollow shell, comprising employing a rotary piercing mill having main rolls disposed in horizontally or vertically opposed relation, with a billet/hollow-shell pass line between, and rotating disc rolls disposed in vertically or horizontally opposed relation between the main rolls, with the pass line between, said main rolls being so arranged as to have a feed angle .beta. and cross angle .gamma. meeting the following conditions:
Apparatus for rotary piercing in seamless tube manufacturing comprising:
Dependencies are inferred from the claim text.