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Title:
DRAWN STEEL PIPE AND RACK BAR, AND DRAWN STEEL PIPE MANUFACTURING DEVICE AND MANUFACTURING METHOD
Document Type and Number:
Japanese Patent JP2021030251
Kind Code:
A
Abstract:
To improve dimensional accuracy of a drawn steel pipe whose wall thickness changes in an axial direction.SOLUTION: The drawn steel pipe has a first processing part 120 of a small diameter, a second processing part 121 of a large diameter, and a taper part 122 between the first processing part 120 and the second processing part 121. A plug 102 in the state that the second processing part 121 is located inside an outlet part 110 of a die 101 is moved at a movement speed, which is 100% or less of a drawing speed of an element pipe W, in a direction opposite to a drawing direction while drawing the element pipe W by use of the plug 102, in which a gradient θ2 of the taper part 122 is greater than 0 and 3° or less, and the die 101 to locate the first processing part 120 inside the outlet part 110 thereby forming a transition part 13, which transitions from a thin wall part 12 to a thick part 14, on the element pipe W, and a depth of an annular recess 15, which is formed on an outer peripheral surface of the transition part 13, is so made as to be 0.2 mm or less.SELECTED DRAWING: Figure 1

Inventors:
UEMOTO TOSHIFUMI
AOKI KENICHI
SUNAGA YORIMASA
Application Number:
JP2019150437A
Publication Date:
March 01, 2021
Filing Date:
August 20, 2019
Export Citation:
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Assignee:
NETUREN CO LTD
International Classes:
B21C1/24; B21C1/00; B21C3/16; B21K21/16; B62D3/12
Attorney, Agent or Firm:
Patent Business Corporation Koei Patent Office