Pipe jacking circular hole pattern for preparing steel pipe

Abstract

The utility model provides a pipe-jacking round pass for preparing a steel pipe, the pass is formed by three rollers, the surface of each roller occupies a 120-degree circumferential angle of the pass, the pass corresponding to the surface of one roller is divided into an arc part and two elliptic arc parts, and the two elliptic arc parts are respectively positioned on two sides of the arc part. According to the pipe jacking round hole pattern, the uniform wall thickness can be well achieved during pipe jacking, the problem that deviation correction is weak due to the fact that a pipe jacking longitudinal rolling mill set is used for aligning the uneven wall thickness of a perforated hole is solved, and the uneven wall thickness level of a pipe jacking unit is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to special steel equipment preparation field, especially a kind of for preparing the pipe round hole of top pipe. BACKGROUND

[0002] Top pipe machine is longitudinal rolling deformation, generally has 5~13 deformation stands from big to small, 3 passive rollers are installed in the stand, and the stand is arranged in 60° cross. Top pipe deformation, the wall thickness of the previous process perforated pipe (load surface, transverse) is uneven, and the deformation of thick place is larger, so it has certain improvement wall thickness uneven effect. The hole type of top pipe deformation is oval hole type, and the wall thickness of steel pipe from hole top to hole bottom (roll gap) is gradually thickened, and cross-rolling is carried out, the metal of hole top and hole bottom is exchanged, but the metal of hole waist is still the metal of hole waist, so the inherent wall thickness uneven of hole waist has negative effect and decisive effect on the wall thickness uneven of steel pipe. Top pipe unit belongs to longitudinal rolling deformation unit, and the wall thickness uneven of relative oblique rolling unit is relatively poor.

[0003] Wall thickness uneven is the key and difficult control project of steel pipe production, and the level of wall thickness uneven basically reflects the level of unit geometry size. Wall thickness uneven quality problem affects the lightweight requirement of steel pipe, quality standard capacity and market demand. Especially boiler pipe, gas cylinder pipe and other pressure vessel pipes and petroleum drill pipe have higher requirements on minimum wall thickness and wall thickness uneven quality, and top pipe unit cannot meet the user demand well. How to overcome the inherent wall thickness uneven of hole type (hole waist), improve the wall thickness uneven of steel pipe and reduce the wall thickness uneven gap with oblique rolling unit becomes an important research topic. The importance of wall thickness uneven and the deficiency of top pipe machine need to develop a design of top pipe round hole type to obtain steel pipe with improved wall thickness uneven, and better meet the quality requirements of users on wall thickness uneven of steel pipe. UTILITY MODEL CONTENTS

[0004] The utility model discloses a kind of top pipe round hole types for preparing steel pipe, keep hole type short axis and long axis unchanged, in hole top to hole waist 6° portion (hole body) using circular arc, in the rest of hole foot portion using elliptic arc, the tangent (transition round smooth) of hole body's true circle and hole foot's eccentric circle (see round hole type Figure 2 ), It is applicable to all in use top pipe hole type improvement.

[0005] To achieve the above object, the utility model provides the following technical scheme:

[0006] A kind of top pipe round hole type for preparing steel pipe, the hole type is formed by 3 rollers, the surface of each roller occupies 120 ° circumferential angle of the hole type, the surface of one roller corresponds to hole type and is divided into circular arc part and two elliptic arc parts, and two elliptic arc parts are located on the two sides of the circular arc part respectively.

[0007] Further, in the pipe piercing round pass for preparing a steel pipe described above, the central angle of the circular arc portion is 72°, and the central angle of one of the elliptical arc portions is 24°.

[0008] Further, in the pipe piercing round pass for preparing a steel pipe described above, the short axis and the long axis of the pass are constant, and the circular arc portion and the elliptical arc portion are tangent.

[0009] Further, in the pipe piercing round pass for preparing a steel pipe described above, the connection between the circular arc portion and the elliptical arc portion is smoothly transitioned.

[0010] Further, in the pipe piercing round pass for preparing a steel pipe described above, the foot portion of the pass has a coverage rate of 20% by heavy reduction.

[0011] It can be known from the analysis that the pipe piercing round pass for preparing a steel pipe can better realize uniform wall thickness when piercing, overcomes the problem that the piercing wall thickness deviation is weakly corrected by a piercing longitudinal rolling mill set, and improves the wall thickness deviation level of the piercing mill set. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings are intended to explain the aspects of the present application and are not limiting of the present application. In the drawings:

[0013] Figure 1 FIG. 1 is a schematic view of a pipe piercing round pass according to an embodiment of the present application.

[0014] Figure 2 FIG. 2 is another schematic view of the pipe piercing round pass according to the embodiment of the present application.

[0015] Figure 3 FIG. 3 is a schematic view of an elliptical pass according to the prior art.

[0016] Reference signs: 1 circular arc portion; 2 elliptical arc portion; 3 hole top; 4 hole waist; 5 hole foot. DETAILED DESCRIPTION

[0017] The present application will be described in detail with reference to the drawings, and embodiments will be explained in detail. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, those skilled in the art will clearly understand that modifications and variations can be made in the present application without departing from the scope or spirit of the present application. For example, features shown as or described as part of one embodiment can be used in another embodiment to produce yet another embodiment. Therefore, it is expected that the present application includes such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0018] As Figures 1 to 3 shown, according to the embodiment of the utility model, provide a kind of for preparing steel pipe's top pipe round pass, as Figure 1 Shown, the pass is formed by 3 rolls, the surface of each roll occupies the 120 ° circumferential angle of the pass, the surface of one roll corresponds to the pass and is divided into arc section 1 and 2 elliptical arc section 2, 2 The elliptical arc section 2 is located at the two sides of the arc section 1 respectively.

[0019] Further, the central angle of the arc section 1 is 72 °, the central angle of one elliptical arc section 2 is 24 °. The sum of the central angle of one arc section 1 and the central angle of 2 elliptical arc section 2 is 120 °.

[0020] Further, the short axis and long axis of the pass are unchanged, the arc section 1 and the elliptical arc section 2 are tangent.The junction of the arc section 1 and the elliptical arc section 2 is smoothly transitioned.The foot part of the pass is 20 % of the re-rolling coverage.The wall thickness unevenness of the prepared steel pipe is improved from 13 % to 10 %.

[0021] As Figure 2 Shown, the middle point of the 120 ° circumferential angle of the pass is hole top 3, the position of 30 ° from hole top 3 to both sides is hole waist 4, and the position of 30 ° central angle from hole waist 4 to both ends is hole foot 5 (the foot part of the pass).

[0022] The inherent wall thickness unevenness of the existing pass (hole waist 4) is analyzed and calculated. The existing elliptical pass is shown in Figure 3 In the triangle Y00' composed of hole waist length X, eccentric amount E and circle radius R, the waist and eccentric angle is 150 °, the opposite side R of the angle and the adjacent side E of the angle. First, the cosine value of the angle α between hole waist length X and circle radius R is obtained by using the sine theorem, and then the hole waist length X is obtained by using the cosine theorem.

[0023] The wall thickness at hole top 3, the wall thickness at top waist, the average thickness of steel pipe, the wall thickness at top waist and the wall thickness at top, the wall thickness unevenness absolute value, the percentage of the wall thickness unevenness absolute value and the average thickness of steel pipe, and the wall thickness unevenness (percentage) are known.

[0024] The circle radius of the elliptical arc of the hole foot part of the present application is calculated, and the parameters of the top pipe round pass are determined.

[0025] The round pass of the utility model is shown in Figure 1, the hole body (the hole top 3 to the hole waist 4 is 6° lower part) adopts the circular arc of the non-biased circle, the circle radius is the short half axis a. The hole foot 5 adopts the elliptical arc of the larger eccentricity, the circle radius is larger. The uneven wall thickness part of the hole type foot part should ensure the sufficient heavy rolling coverage, the heavy rolling coverage of the uneven wall thickness (36°-24°) / 60° is 20% which is sufficient. In the triangle B00' composed of the long half axis b, the eccentricity E (R-a, the circle radius R of the elliptical arc-short half axis a), the circle radius R, the long half axis and the eccentricity angle 156° are known, and the two side lengths of the long half axis b and the eccentricity E (R-a, the implied known). The circle radius R of the elliptical arc can be obtained by using the cosine theorem.

[0026] The hole deformation before the pipe jacking and the reducing deformation after the pipe jacking are not changed, and are carried out according to the conventional design specification.

[0027] Embodiment

[0028] The pipe jacking round hole type design of using the circular arc of the non-eccentric circle of the hole body and the elliptical arc of the larger eccentricity of the hole foot is carried out on the pipe jacking round hole type design process of the hole type number "A10 new". The specific method is as follows:

[0029] The core rod is 105. The basic parameters of "A10 new" determined by the pipe jacking deformation design: the hole type ellipticity coefficient ζ = 1.02155 (ζ = b / a), the hole type short half axis a = 58, and the hole type long half axis b = 59.25.

[0030] The round hole type is shown in Figure 2 , the hole type angle is 120°, the hole type half angle is 60°, the hole body half angle is 36°, the uneven wall thickness heavy rolling coverage (36°-24°) / 60° is 20%, the non-eccentric circle radius of the hole body = the hole type short half axis a = 58, the hole bottom round angle r = 8, the normal circle of the hole body and the eccentric circle of the hole foot 5 are tangent, and the elliptical arc circle radius of the hole foot 5 eccentricity is calculated by the following formula:

[0031] In the triangle B00' composed of the long half axis b, the eccentricity E (R-a, the circle radius R of the elliptical arc-short half axis a), the circle radius R:

[0032] R 2 = (R-a) 2 +b 2 -2(R-a)b*cos156°

[0033] R = (a 2 +b 2 +2ab*cos156°) / (2a+2b*cos156°)

[0034] a = 58, b = 59.25, cos156° = -0.9135454576, and R = 76.92 is obtained.

[0035] The eccentricity of the elliptical arc of the hole foot is E=Ra=76.92-58=18.92.

[0036] The hole top wall thickness = hole semi-minor axis a58 - half of the core rod ∮105 (52.5%) = 5.5. The hole waist wall thickness (30° downward from the hole top 3) = hole semi-minor axis a58 - half of the core rod ∮105 (52.5%) = 5.5. The inherent wall thickness unevenness of the hole (hole waist 4) = 0%. The parameters of the "A10 New" round hole are shown in Table 1.

[0037] Table 1 Parameters of “A10 New” round hole type

[0038]

[0039]

[0040] The circular hole jacking pipe designed and manufactured by this utility model reduces the unevenness of the steel pipe wall thickness from 13% to 10%. This can better meet the needs of users of steel pipes with strict wall thickness requirements, especially gas cylinder pipes, and achieve market order growth.

[0041] Comparative Example

[0042] Use the traditional top pipe oval hole design, such as Figure 3 As shown in the figure, the elliptical hole design and uneven wall thickness analysis of the hole model "A10" are performed on the top pipe. The specific methods are as follows:

[0043] The core rod is ∮105. The basic parameters of "A10" determined by the deformation design of the top pipe are: the hole ellipticity coefficient ζ=1.02155 (ζ=b / b), the hole short semi-axis a=58, and the hole long semi-axis b=59.25.

[0044] See oval hole Figure 1 , hole angle 120°, hole half angle 60°, hole bottom fillet r=8, hole elliptical arc radius R is calculated by the following formula:

[0045] In the triangle B00' composed of the major semi-axis b, the eccentricity E (Ra, the radius of the elliptical arc R-the minor semi-axis a), and the circle radius R:

[0046] R 2 =(Ra) 2 +b 2 -2(Ra)b*cos120°

[0047] Calculate: R = (a 2 +b 2 +2ab*cos156°) / (2a+2b*cos120°)

[0048] a = 58, b = 59.25, cos 120° = -0.8660254, R = 60.59.

[0049] Eccentricity of elliptical arc E = R - a = 60.59 - 58 = 2.59.

[0050] See the elliptical hole Figure 1 In triangle Y00' composed of hole waist (hole top 3 down 30°) length X, eccentricity E, and circle radius R, the hole waist and eccentricity angle is 150°, the opposite side of the angle is R, and the adjacent side of the angle is E.

[0051] R / sin 150° = E / sin a, the angle between hole waist length X and circle radius R is a.

[0052] sin 2 a = E 2 sin 2 150° / R 2

[0053] cos 2 a = 1 - sin 2 a = 1 - E 2 sin 2 150° / R 2

[0054] Given E = 2.59, R = 60.59, and sin 150° = 0.5, cos a = 0.9997722 is obtained.

[0055] E 2 = R 2 + X 2 - 2RX*cos a

[0056] E 2 = R 2 + X 2 - 2RX*0.9997722

[0057] Given E = 2.59, R = 60.59, and the above formula is arranged as: X 2 -121.144X + 3663.976 = 0

[0058] X1 = 62.789, which is greater than hole type long semi-axis b 59.25, and X2 = 58.355 = X

[0059] Hole top wall thickness S 顶 = 58 - 52.5 = 5.5, hole waist wall thickness S 腰 = 58.355 - 52.5 = 5.855, average hole top and hole waist wall thickness S 腰 = 5.6775.

[0060] Uneven wall thickness of hole top and hole waist 腰 -S 顶 = 0.355,

[0061] Uneven wall thickness of hole top and hole waist (percentage) = Uneven wall thickness of hole top and hole waist / Average wall thickness of hole top and hole = 0.355 / 5.6775*100% = 6.25%.

[0062] Inherent uneven wall thickness of hole type (hole waist) = 6.25%. The parameters of the "A10" elliptical hole type are shown in Table 2.

[0063] Table 2 Parameters of the "A10" elliptical hole type

[0064] Short half axis a of the pass 58 Long half axis b of the pass 59.25 Circular radius R of the elliptical arc of the pass 60.59 Eccentricity E of the pass 2.59 Round corner r of the pass bottom 8 Inherent wall thickness unevenness of the pass (pass belly) 6.25％

[0065] The elliptical hole type top pipe designed by the comparative example has a wall thickness unevenness of 13%. The steel pipe with a relatively strict wall thickness requirement, especially the gas cylinder pipe, cannot better meet the user's demand, and affects the market order shortage.

[0066] The hole body of the utility model is the design of the top pipe round hole type of the non-eccentric circle arc and the larger eccentric elliptical arc of the hole foot, breaks the traditional elliptical hole type design, and innovatively changes to the round hole type. The hole top is changed from 72 degrees to an arc, the hole bottom is changed from 8 degrees to an elliptical arc with a large radius, cross-rolling is carried out, the uneven wall thickness reduction rate is 20%, and the inherent uneven wall thickness of the hole type is 0%. After trial and use, the actual uneven wall thickness is improved from 13% to 10% compared with the same period, and the net improvement is 3%.

[0067] The gas cylinder pipe with a relatively high requirement for uneven wall thickness: when the existing technology elliptical hole type is used, the monthly average quantity is 1207 tons. After the innovative change to the round hole type, the monthly average quantity is 1573 tons, and the increment is 366 tons. The gross profit of the gas cylinder pipe is 200 yuan / ton. The monthly average added benefit = 366 tons*200 yuan / ton = 7.32 thousand yuan, and the annual added benefit = 7.32*12 = 88 thousand yuan.

[0068] From the above description, it can be seen that the utility model discloses a top pipe round hole type for preparing a steel pipe, and breaks the traditional elliptical hole type design of the top pipe. In view of the problem of the inherent uneven wall thickness of the top pipe elliptical hole type, a new hole type design is provided, in which the arc is used for the wall thickness part of the top hole waist. The hole type is composed of two sections, the arc is used for the top hole waist, and the elliptical arc is used for the bottom hole. The front and rear hole types are arranged in cross, the steel pipe is cross-rolled, the uneven wall thickness reduction rate of the bottom hole is ensured to be sufficient, the last two hole types of the top pipe hole type are the same in size, the inherent uneven wall thickness of the top pipe hole type is zero, and therefore, the top pipe process realizes better uniform wall thickness.

[0069] The utility model discloses can better realize even wall thickness when the pipe is jacked, overcome the problem that the pipe jacking longitudinal rolling unit is weak to the uneven wall thickness of the perforation deviation, improve the uneven wall thickness level of pipe jacking unit.

[0070] The above only is the preferred embodiment of the utility model, and is not used to limit the utility model, and the utility model can have various changes and changes for the person skilled in the art. Any modification, equivalent replacement, improvement etc. that is made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A piercer round pass for producing a steel pipe, characterized in that, The pass is formed by three rollers, the surface of each of the rollers occupies 120° of the circumference of the pass, The surface of one of the rollers corresponds to a pass which is divided into a circular arc part and two elliptical arc parts, The two elliptical arc parts are respectively located on the two sides of the circular arc part.

2. The piercer round pass for manufacturing steel pipes according to claim 1, wherein, The central angle of the circular arc part is 72°, and the central angle of one of the elliptical arc parts is 24°.

3. The piercer round pass for manufacturing steel pipes according to claim 1, wherein, The short axis and the long axis of the pass are constant, and the circular arc part and the elliptical arc part are tangent.

4. The piercer round pass for manufacturing steel pipes according to claim 1, wherein, The connection between the circular arc part and the elliptical arc part is smoothly transitioned.

5. The piercer round pass for manufacturing steel pipes according to claim 1, wherein, The foot part of the pass is 20% of the coverage of the heavy rolling.

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