CN204320943U - A kind of spiral steel pipe bottlenecking rounding die - Google Patents

Abstract

The utility model relates to a diameter-reducing full circle mold for spiral steel pipe ends, which comprises an upper mold and a lower mold. The semicircular inner cavities of the upper mold and the lower mold have a slope along the axial direction, and the inner cavity is in the shape of Conical shape. The surfaces of the upper mold and the lower mold are respectively removed by 7-10mm at the mold-closing place, that is, a gap of 14-20mm is left between the upper mold and the lower mold after mold-closing. The slope of the semicircular inner cavity of the upper mold and the lower mold is In the formula: D-theoretical diameter of standard specification steel pipe; B-die width. The mold width B is 200-300 mm. Compared with the prior art, the beneficial effects of the utility model are: 1) adopt the cold shrinking method, and use a press to complete the rounding operation of the steel pipe end diameter, which is fast and efficient; The smooth transition between them is beneficial to ensure the surface quality of the steel pipe; 3) Make full use of the full-circle station press, and carry out diameter reduction treatment at the last full-circle station without affecting normal production.

Description

A full circle mold for reducing the diameter of the spiral steel pipe end

technical field

The utility model relates to the technical field of steel pipe end trimming, in particular to a diameter-expanding and rounding mold for the end of a spiral steel pipe.

Background technique

In the construction of long-distance oil and gas pipelines, in order to facilitate the end-to-end welding of steel pipes, it is necessary to ensure that the diameter and ellipticity of the pipe ends on both sides of the butt steel pipes are close to the same within a certain length range, and the tolerance requirements are relatively strict. Therefore, in the production process of the spiral steel pipe, it is necessary to go through the pipe end trimming process to ensure the dimensional accuracy and eliminate the internal stress. However, in the actual production of the spiral steel pipe, due to the fluctuation of the mechanical properties of the steel plate, the inaccurate estimation of the influence of factors such as springback, etc., Often there is a phenomenon that the diameter of the pipe end is out of tolerance.

If the diameter of the pipe end of the steel pipe is too small, the diameter of the pipe end can be expanded, while for the steel pipe with a relatively large diameter of the pipe end, the method of cutting the pipe end is usually adopted. However, for long-distance oil and gas pipelines, there are also strict requirements on the length of steel pipes. The steel pipes after pipe end removal often fail to meet the delivery length requirements. In addition, the pipe end removal method reduces the delivery settlement weight, which seriously affects the economic benefits of enterprises.

The Chinese patent application number 201320391619.0 (application date is July 2, 2013) discloses a "tube end thermal shrinkage mold", the mold body "has a columnar inner cavity, along the axial direction of the cylindrical inner cavity It includes an introduction section, a deformation section and a flat section, the taper of the inner surface of the introduction section is set between 40-60 degrees, the taper of the inner surface of the deformation section is set before 1.5-2.5 degrees, and the inner surface of the flat section The taper is set to 0 degrees." This mold is a thermal shrinkage mold, which needs to heat the end of the steel pipe, which increases the tooling and investment. In addition, the taper is set in sections, and the transition of the steel pipe shrinkage is not smooth, which is likely to be unfavorable to the surface quality. Influence.

Utility model content

The utility model provides a diameter-reducing round mold for the end of a spiral steel pipe, which can be quickly completed on ordinary pressure equipment by adopting a cold-reducing method, and fully considers the smooth transition between the pipe end and the diameter of the steel pipe body, and the diameter-reducing The diameter and roundness of the end of the steel pipe can meet the standard requirements.

In order to achieve the above object, the utility model adopts the following technical solutions to realize:

A diameter-reducing full-circle mold for spiral steel pipe ends includes an upper mold and a lower mold. The semicircular inner cavity of the upper mold and the lower mold has a slope along the axial direction, and the inner cavity is in the shape of a truncated cone after the molds are closed.

The surfaces of the upper mold and the lower mold are respectively removed by 7-10mm at the mold-closing place, that is, a gap of 14-20mm is left between the upper mold and the lower mold after mold-closing.

The gradient of the semicircular inner cavity of the upper mold and the lower mold is In the formula: D-theoretical diameter of standard specification steel pipe; B-die width.

The mold width B is 200-300 mm.

Compared with the prior art, the beneficial effects of the utility model are:

1) Using the cold shrinking method, using the press to complete the rounding operation of the steel pipe end diameter, fast and efficient;

2) The smooth transition between the reduced diameter pipe end and the diameter of the steel pipe body is conducive to ensuring the surface quality of the steel pipe;

3) Make full use of the full-circle station press. After checking the diameter of the pipe end is out of tolerance, the steel pipe only needs to be marked and then proceed according to the normal process flow. The diameter reduction treatment is performed at the last full-circle station without affecting normal production.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a cross-sectional view along line A-A of Fig. 1 .

In the picture: 1 upper mold 2. lower mold

Detailed ways

The specific embodiment of the utility model will be further described below in conjunction with accompanying drawing:

See Fig. 1-Fig. 2, it is the structure schematic diagram of the present utility model, and the utility model a kind of spiral steel tube pipe end shrinkage round mold, comprises upper mold 1 and lower mold 2, the half of described upper mold 1 and lower mold 2 The circular inner cavity has a slope along the axial direction, and the inner cavity is in the shape of a truncated cone after the mold is closed. The ribs and bolt holes for installation are not shown in the figure, and the installation method is the same as that of ordinary molds.

The surfaces of the upper mold 1 and the lower mold 2 are respectively removed by 7-10mm at the mold-closing place, that is, a gap of 14-20mm is left between the upper mold and the lower mold after mold-closing.

The gradient of the semicircular inner cavity of the upper mold 1 and the lower mold 2 is In the formula: D-theoretical diameter of standard specification steel pipe; B-die width.

The mold width B is 200-300 mm.

The working principle of a spiral steel pipe end shrinking round mold of the utility model is to design the inner cavity of the mold according to the theoretical diameter and diameter reduction rate of the standard steel pipe, and use a press to press the spiral steel pipe end to make the pipe end The diameter accuracy and roundness meet the standard requirements.

The use method of a spiral steel pipe end diameter reduction full circle mold of the utility model is as follows:

Process and manufacture molds according to the theoretical diameter and theoretical diameter reduction ratio of standard steel pipe ends, and install the molds on the press; hoist the steel pipes to be reduced on the steel pipe brackets, and adjust the steel pipe brackets so that the steel pipe shrinkage ends are aligned with the molds; Start the press to pressurize the diameter reduction operation, measure the diameter and roundness of the steel pipe, and if it meets the standard requirements, it is qualified.

According to the requirements of the standard API SPECIFICATION 5L "Pipeline Steel Pipe Specification" (45th Edition), the tolerance of the diameter of the steel pipe end is D±1.6, within this range it is a qualified steel pipe, and those that exceed the tolerance are unqualified products; at the same time, according to the API standard: "8.9.2 Unless otherwise agreed, the sizing ratio of cold-expanded steel pipes shall not be less than 0.003 and shall not be greater than 0.015. 8.9.3 Unless otherwise agreed, the sizing ratio Sr shall be calculated by formula (1):

Sr＝|Da-Db|/Db...Formula (1)

Da refers to the outer diameter after sizing specified by the manufacturer, expressed in mm (in);

Db refers to the outer diameter before sizing specified by the manufacturer, expressed in mm (in);

|Da-Db| refers to the absolute value of the outer diameter difference, expressed in mm (in);”

The utility model sets the diameter reduction ratio of the steel pipe within the range of 0.3% to 1.5%, and the diameter reduction ratio is the ratio of the diameter reduction amount to the diameter of the steel pipe, that is, (D1-D)/D1=(0.003～0.015), where D is Theoretical diameter of standard steel pipe, D1 is the diameter of the steel pipe before diameter reduction; the slope of the inner cavity of the reduced diameter mold K=(D1-D)/2B, where B is the width of the mold, and the slope of the inner cavity of the mold is calculated as $K=(0.0015~0.0075)\frac{\mathrm{D.}}{B}.$

In order to avoid damage to the equipment caused by the collision of the upper and lower molds when the diameter is reduced, a certain gap must be left between the upper and lower molds. If the gap is too large, it is easy to cause concave phenomenon when the thin-walled steel pipe is reduced. Therefore, it is set at 14-20mm In between, 7 to 10 mm of the opposite surfaces of the upper mold 1 and the lower mold 2 are respectively processed and removed.

The following examples are carried out on the premise of the technical solution of the utility model, and detailed implementation and specific operation process are provided, but the protection scope of the utility model is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[Example 1] The diameter reduction operation of the spiral steel pipe whose specification is D630×8

Mold making: The theoretical diameter of D630×8 standard steel pipe is 630mm, set the mold width B=200mm, and take the coefficient as 0.005, then the slope of the mold cavity That is, the size of the large diameter end is 636.4mm, the size of the small diameter end is 630mm, and the theoretical diameter reduction rate is 1%, which meets the requirements.

In this embodiment, the tolerance of the pipe end diameter of the steel pipe is D±1.6, that is, the diameter of the pipe end is qualified within the range of (631.6-628.4) mm, and the measured diameter of the steel pipe to be reduced is 633.7 mm, and the outer diameter of the steel pipe after diameter reduction is measured It is 630.2mm, and the actual diameter reduction rate is 0.5%, which meets the requirements of product standards.

Claims (4)

1. a spiral steel pipe end reducing diameter full circle mold, it is characterized in that, comprises upper mold and lower mold, and the semicircle inner cavity of described upper mold and lower mold has slope along the axial direction, and inner cavity after mold closing The body is conical in shape. 2. A kind of spiral steel pipe end shrinking round mold according to claim 1, characterized in that, the surfaces of the upper mold and the lower mold at the mold closing place are respectively removed by 7 to 10 mm, that is, after the mold closing, the upper and lower molds are respectively removed. Leave a gap of 14-20mm between the lower molds. 3. a kind of helical steel pipe pipe end shrinkage full circle mold according to claim 1, is characterized in that, the inclination of described upper mold and lower mold semicircle inner cavity is In the formula: D-theoretical diameter of standard specification steel pipe; B-die width. 4 . The diameter-reducing full circle mold for spiral steel pipe end according to claim 3 , characterized in that, the width B of the mold is 200-300 mm.