Method for producing seamless pipe

A manufacturing method and technology for seamless pipes, which are applied in the directions of manufacturing tools, metal rolling, metal rolling, etc., can solve the problems of uniform sintering and shortening of the service life of the plug.

Inactive Publication Date: 2011-02-23
SUMITOMO METAL IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the removal amount of the oxide film must be carefully adjusted. If the film thickness is loosened and the film thickness is too thin, problems such as sintering of the entire part and a reduction in the service life of the plug may occur.

Method used

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  • Method for producing seamless pipe
  • Method for producing seamless pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0102] For the steel types having the chemical compositions shown in Table 1, a φ70 round billet was cut from the center portion of a φ225 round billet produced by continuous casting by billet rolling as a test material. As for the guide part, use disc-shaped rolls, change the shape of the main roll and the shape of the plug to perform piercing and rolling under the manufacturing conditions shown in Table 2 or Table 3, and measure the roughness of the inner surface of the hollow shell (defined in the JIS-0601 standard maximum height Rz).

[0103] [Table 1]

[0104] Table 1

[0105]

[0106] [Table 2]

[0107] Table 2

[0108] heating temperature

1180℃～1240℃

Tilt angle β

7°～16°

Main roll chisel diameter D 1

φ350~φ410mm

Main roll exit face angle θ r

3°～5.5°

Roll diameter ratio D 2 / D 1

0.9～1.3

Δθ=θ p -θ r

-0.25°～1.0°

Hollow tube outer diameter

70.0~75.0mm

Hollow tube blan...

Embodiment 2

[0118] After the continuous casting material having the chemical composition shown in Table 1 is made into a round billet of φ191 by billet rolling, 100 round billets with an outer diameter of φ73 , wall thickness t5.51 seamless steel pipe, and its inner surface characteristics were investigated. The results are shown in Table 5.

[0119] [Table 4]

[0120] Table 4

[0121] heating temperature

1240℃

Tilt angle β

6°～16°

Main roll chisel diameter D 1

φ1400mm

[0122] Main roll exit face angle θ r

3°～4°

Roll diameter ratio D 2 / D 1

1.05～1.15

Δθ=θ p -θ r

-1.5°～1.25°

Head leveling number R n

0.8～3.5

[0123] [table 5]

[0124] table 5

[0125]

[0126] However, the meanings of A to E in the above table are as follows.

[0127] A: Calculated value of "Rn-(-0.37×Δθ+1.47)".

[0128] B: Calculated value of "Rn-(-0.24×Δθ+1.73)".

[0129] C: Calculated value of "0...

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Abstract

A method for producing a seamless pipe by performing the piercing rolling of round billets heated to 1250 DEG C or less by means of a piercer where plugs are arranged along a pass line between a pair of inclined rolls and a pair of guide means arranged opposed to each other around the pass line, wherein perforated rolling is performed under conditions which satisfy following expressions (1) to (3): -1.0p<DeltaTheta ...(1), DeltaTheta-Thetap-Thetar... (2), -0.37xDeltaTheta+1.47<=Rn<=0.37xDeltaTheta+2.67 ... (3) wherein the meaning of each symbol in the expressions is as follows. Thetar: half angle ( DEG ) that the pass line and a main roll surface make under a state where the angle of inclination of the main roll is zero, Thetap: half angle ( DEG ) that the pass line and a reeling portion of the plug make, and, Rn: number of times of reeling the plug. Therefore, the invention can inhibit corrugation defect of the seamless pipe.

Description

technical field [0001] The present invention relates to a method for manufacturing seamless pipes. Background technique [0002] As a method for manufacturing seamless pipes, the Mannesmann pipe method is known, that is, after piercing and rolling a heated round billet with a piercing machine, it is carried out by a mandrel mill, a mandrel mill, etc. Stretching and rolling, and then sizing and rolling by a sizing machine to obtain a seamless pipe. [0003] The piercer is usually a piercer with the following components: a rolling roll composed of a cylindrical or conical pair of main rolls (also called "slanted rolls"); guide blocks, disc rolls, roll guides, etc. Component; an internal surface limiting tool called a plug. [0004] figure 1 It is a schematic diagram showing an example of a cross-roll piercer using a tapered inclined roll, figure 2 yes means figure 1 A schematic diagram of the A-A line profile. image 3 It is a figure which schematically shows the plug s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B27/02B21B19/04
CPCB21B25/00B21B19/04B21B27/025
Inventor 稻毛孝光山川富夫下田一宗
Owner SUMITOMO METAL IND LTD
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