Title:
METHOD FOR PREVENTING COLD PILGER INNER FACE CRACK
Document Type and Number:
Japanese Patent JP3401434
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent the inner face of a tube to be rolled from generating a crack by making a Q value and T. Red a specific value so that tensile stress generated at a Pilger rolling time is crossed to metal fibers by using a base tube is which the metal fibers have an angle for the tube axial direction.
SOLUTION: A stock billet 1 is heated to a prescribed temp., is pierced and rolled by a piercer roll 2 and is made to a hollow base tube 3 in which metal fibers have an angle for the tube axial directionn. The rolling is conducted under a Q value of ≥0.4 and T.Red of ≤80% while satisfying the absolute value of the Q value=thickness working rate/outer shape working rate=1n(t1/t0)/1n(dm1/dm0) and the formula of the T.Red=area reduction rate (%)=(1-dm1×t1/dm0×t0)×100, wherein t0=base tube thickness, t1=product thickness, d0=base tube outer diameter, dm0=d0-t0 and dm1=d1-t1.
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Inventors:
Honda Chikasada
Application Number:
JP16538398A
Publication Date:
April 28, 2003
Filing Date:
June 12, 1998
Export Citation:
Assignee:
Sanyo Special Steel Co., Ltd.
International Classes:
B21B19/04; B21B21/00; (IPC1-7): B21B21/00; B21B19/04
Domestic Patent References:
| JP7102317A | ||||
| JP5212417A | ||||
| JP4127902A |
Other References:
【文献】第47回鋼管部会継目無鋼管文科会資料 共通議題「冷間加工技術と設備の保守管理について」(資料編),日本,1973年11月25日,P.52
Attorney, Agent or Firm:
Tsuyoshi Shiina
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