CN114593971B - Rolling flattening method for steel pipe plate strip-shaped transverse tensile sample - Google Patents
Rolling flattening method for steel pipe plate strip-shaped transverse tensile sample Download PDFInfo
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- CN114593971B CN114593971B CN202210311945.XA CN202210311945A CN114593971B CN 114593971 B CN114593971 B CN 114593971B CN 202210311945 A CN202210311945 A CN 202210311945A CN 114593971 B CN114593971 B CN 114593971B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D1/00—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling
- B21D1/02—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling by rollers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
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Abstract
The invention provides a rolling flattening method of a steel pipe plate strip-shaped transverse tensile sample, which solves the problem that the yield strength is reduced by the existing flattening method, reasonably controls the Banschinger effect by unifying and standardizing the rolling flattening method, ensures that the test result of the transverse yield strength of the steel pipe sample is stable, reliable and comparable, and comprises the following steps: cutting a lath-shaped transverse tensile sample with the arc length of about 2a +4t on the steel pipe, wherein 2a is more than or equal to 350mm, and t is the thickness of the sample; the upper press roll consists of 2 round rolls with axle center distance of l, and the lower support roll is a driving rotary round roll; placing the right end of the sample between the upper pressing roller and the lower supporting roller, and moving the upper pressing roller and the sample downwards until the lower surface of the sample is contacted with the lower supporting roller; pressing down the upper roller by (D-t)/2- ((D-t) 2 /4‑l 2 /4) 1/2 +l 2 /(6t(E/σ t -1)) D is the steel pipe outside diameter; e is the modulus of elasticity; sigma t The rated tensile strength of the material; rotating the lower supporting roll to enable the sample to move rightwards, and flattening the rest part of the sample; and moving the upper compression roller upwards, taking out the sample, and cutting off a certain length at two ends respectively to obtain the final sample.
Description
Technical Field
The invention relates to the technical field of flattening methods for arc-shaped samples.
Background
The oil and gas transmission pipeline is an energy source aorta. Prevention of plastic deformation of pipeline steel pipes in operation is a fundamental criterion for pipeline design. The main stress of the pipeline is the hoop direction, and the hoop yield strength is the most important index for pipeline design. The hoop yield strength of the steel pipe can be tested by a rod-shaped sample, a plate-shaped sample, an expanding ring sample and a hydrostatic pressure sample. The rod-shaped sample, the expansion ring and the hydrostatic pressure sample are respectively limited due to the requirement on the minimum diameter of the sample, high processing cost and large use of test cost; plate-like samples are the basic choice for detection.
During processing of the plate-shaped sample, the steel plate with the radian needs to be flattened firstly, different flattening methods cause different Banschinger effects, the detection results of different test mechanisms have larger difference, and great trouble is caused to normal inspection and judgment of the steel pipe.
Disclosure of Invention
The invention provides a rolling flattening method of a steel pipe lath-shaped transverse tensile sample, which solves the problem that the yield strength of the steel pipe lath-shaped transverse tensile sample is reduced by the traditional steel pipe lath-shaped transverse tensile sample flattening method.
The process for flattening the steel pipe plate strip-shaped transverse tensile sample can be divided into 6 steps.
1) According to the relevant standard requirements, the length of a test sample is generally required to be 350mm, a lath-shaped transverse tensile test sample raw material is cut at a specific position of a steel pipe, the arc length is about 350mm +4t, and the width is 80mm, as shown in figure 1. In the case of flame cutting, the width should be properly enlarged to avoid heat input to the final sample.
2) One end of the lath-shaped test piece 3 is placed between the upper press roll 2 and the lower press roll 1 as shown in fig. 2. The upper press roll 2 consists of 2 round rolls with the diameter of 140mm and can move up and down. The lower supporting roller 1 is a circular roller which actively rotates and has the diameter not less than 400 mm. And (3) moving the upper press roll 2 downwards slowly until the upper surface and the lower surface of the lath-shaped sample 3 are just contacted with the upper press roll 2 and the lower press roll 1, and ensuring that one end of the upper surface of the sample 3 is tangent to the round roll close to the end of the sample in the upper press roll.
3) On the basis of the above, the following steps are carried outThe press roll 2 is pressed down by (D-t)/2- ((D-t) as shown in FIG. 3 2 /4-l 2 /4) 1/2 +l 2 /(6t(E/σ t -1)) the distance between the two circular roll axes in the upper press roll, i =160mm, see fig. 2; d is the outer diameter of the steel pipe, mm; t is wall thickness, mm; e is the elastic modulus, MPa; sigma t The material rated tensile strength is MPa. The position of the sample 3 should be kept stable at this time.
4) The lower support roll 1 is gradually rotated slowly at a speed of about 5-10mm/s to allow the sample 3 to gradually move from the other end to the one end, so that the remaining portion of the sample 3 is also gradually flattened, as shown in fig. 4.
5) The upper pressure roller 2 is lifted a sufficient distance to ensure that the sample 3 can be removed. The sample after removal was still bent at both ends as shown in FIG. 5. At the moment, only the flatness of 350mm in the middle is checked, if the flatness does not meet the requirement, the sample is placed between the upper compression roller and the lower support roller, the upper surface of the sample is contacted with two round rollers in the upper compression roller, the upper compression roller and the sample move downwards until the lower surface of the sample is contacted with the lower support roller, the upper compression roller slightly presses downwards, the lower support roller is rotated, and the 350mm long part in the middle of the sample is gradually flattened.
6) Then, the sample 3 shown in FIG. 5 was cut at both ends thereof by 2t, and the final sample was further processed as shown in FIG. 6.
By using the rolling flattening method, the overpressure radius/depression amount in the rolling flattening process is calculated, so that the flatness of a sample can meet the requirement after one-time flattening, and the operation that the overpressure parameter is inaccurate, multiple times of flattening and repeated flattening are required in the flattening process of the existing method is avoided.
Drawings
FIG. 1 is a schematic view of a transverse tensile specimen in the form of a slab cut from a steel pipe.
Fig. 2 is a schematic view when one end of a sample is interposed between an upper press roller and a lower press roller.
Fig. 3 is a schematic view after the upper roll is pressed down.
Fig. 4 is a schematic view of the lower support roller rotating to flatten the sample.
FIG. 5 is a schematic illustration of a sample after flattening.
FIG. 6 is a schematic view of a test piece with bent sections at both ends cut away.
Detailed Description
Example 1:
the transverse yield strength test was performed on phi 508 × 22mm × 70 straight welded steel pipes, and was performed as follows.
1) According to the relevant standard requirements, the raw material of the lath-shaped transverse tensile sample 3 is cut at the position of 90 degrees from the welding line of the steel pipe, the arc length is about 440mm, and the width is 100mm, as shown in figure 1. Because of the flame cutting, the effect of the edge heat input on the final sample was taken into account.
2) The right end of the lath-like test piece 3 is put between the upper press roll 2 and the lower press roll 1 as shown in fig. 2. The upper press roll 2 consists of 2 round rolls with the diameter of 140mm and can move up and down. The lower support roller 1 is a circular roller with a diameter of 400mm which rotates actively. And (3) moving the upper press roller 2 downwards slowly until the upper surface and the lower surface of the lath-shaped sample 3 are just contacted with the upper press roller 2 and the lower press roller 1, and the upper surface of the right end of the sample 3 is tangent to a round roller at the middle and right end of the upper press roller.
3) The upper roll 2 is then pressed downwards, as shown in figure 3,
the amount of pressing is according to
D＝508,t＝22,l＝188,E＝210000MPa,σ t =670MPa calculation:
the pressing amount was 19.77mm, and the position of the sample 3 was kept stable after the pressing.
4) The lower backing roll 1 was gradually rotated slowly at a speed of about 6mm/s to allow the sample 3 to gradually move to the right, causing the remainder of the sample 3 to also gradually flatten out, as shown in figure 4.
5) The upper roller 2 is lifted a sufficient distance to remove the sample 3. The sample after removal was still bent at both ends as shown in FIG. 5. The flatness of the middle 350mm length was examined.
6) Then, the sample 3 shown in FIG. 5 was cut at both ends thereof by a length of 44mm, and the final sample was further processed as shown in FIG. 6.
Example 2:
the transverse yield strength test is carried out on the phi 609 multiplied by 18mmX65 straight weld steel pipe of the shale gas well in the following way.
1) According to the relevant standard requirements, the raw material of the lath-shaped transverse tensile sample 3 is cut at the position of 90 degrees from the welding line of the steel pipe, the arc length is about 440mm, and the width is 100mm, as shown in figure 1. Because of the flame cutting, the effect of the edge heat input on the final sample was taken into account.
2) The right end of the lath-like test piece 3 is put between the upper press roll 2 and the lower press roll 1 as shown in fig. 2. The upper press roll 2 consists of 2 round rolls with the diameter of 140mm and can move up and down. The lower supporting roller 1 is a circular roller with the diameter of 500mm and actively rotates. And (3) moving the upper pressing roller 2 downwards slowly until the upper surface and the lower surface of the lath-shaped sample 3 are just contacted with the upper pressing roller 2 and the lower supporting roller 1, and the upper surface of the right end of the sample 3 is tangent to the round roller at the middle and right end of the upper pressing roller.
3) The upper roll 2 is then pressed downwards, as shown in figure 3,
the amount of pressing is according to
D＝609,t＝18,l＝201,E＝210000MPa,σ t =572MPa calculates:
the amount of pressing was 18.64mm, and the position of sample 3 was kept stable after pressing.
4) The lower backing roll 1 was gradually rotated slowly at a speed of about 7mm/s to allow the sample 3 to gradually move to the right, causing the remainder of the sample 3 to also gradually flatten as shown in figure 4.
5) The upper roller 2 is lifted a sufficient distance to remove the sample 3. The sample after removal was still bent at both ends as shown in FIG. 5. The middle 350mm length was checked for flatness.
6) Then, 36mm lengths were cut at both ends of the sample 3 shown in FIG. 5, and the final sample was further processed as shown in FIG. 6.
Claims (4)
1. A rolling flattening method for a steel pipe plate strip-shaped transverse tensile sample is characterized by comprising the following steps:
1) Cutting a slab-shaped transverse tensile sample on the steel pipe, wherein the arc length 2a +4t of the sample is more than or equal to 350mm, the width of the sample is not less than 80mm, and t is the wall thickness of the steel pipe;
2) The upper press roll consists of 2 round rolls with the diameter of 140mm and can move up and down; the lower supporting roller is a circular roller which actively rotates and has the diameter not less than 400 mm; the upper press roll is positioned above the lower support roll, the axial center distance l of two round rolls in the upper press roll is 150-210mm, and the two round rolls are in bilateral symmetry with the axis of the lower support roll;
placing the right end of a sample between an upper press roller and a lower support roller, wherein the upper surface of the sample is contacted with two round rollers in the upper press roller, and the rightmost end of the upper surface of the sample is tangent to a right round roller in the upper press roller; moving the upper press roller and the sample downwards until the lower surface of the sample is contacted with the lower support roller;
3) Pressing down the upper roller by (D-t)/2- ((D-t) 2 /4-l 2 /4) 1/2 +l 2 /(6t(E/σ t -1)) D is the outside diameter of the steel pipe, mm; e is the elastic modulus, MPa; sigma t The material rated tensile strength is MPa;
4) Rotating the lower supporting roll at the speed of 5-10mm/s, and gradually moving the sample to the right to gradually flatten the rest part of the sample;
5) Moving the upper compression roller upwards, and taking out the sample;
6) The two ends of the sample are cut off for a length of not less than 2t respectively to obtain a final sample with a length of 350mm in the middle.
2. The roll flattening method of claim 1, wherein: and 5) checking the flatness of the middle 350mm of the sample, if the flatness does not meet the requirement, putting the sample between an upper compression roller and a lower support roller, contacting the upper surface of the sample with two round rollers in the upper compression roller, moving the upper compression roller and the sample downwards until the lower surface of the sample is contacted with the lower support roller, slightly pressing the upper compression roller downwards, and rotating the lower support roller to gradually flatten the middle 350mm part of the sample.
3. The roll flattening method of claim 1, wherein: the axial distance l between two round rollers in the upper pressing roller is 160-200mm.
4. The roll flattening method according to claim 1, wherein: and cutting the lath-shaped transverse tensile sample on the steel pipe by flame, wherein the width of the sample is 100mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210311945.XA CN114593971B (en) | 2022-03-28 | 2022-03-28 | Rolling flattening method for steel pipe plate strip-shaped transverse tensile sample |
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| CN202210311945.XA CN114593971B (en) | 2022-03-28 | 2022-03-28 | Rolling flattening method for steel pipe plate strip-shaped transverse tensile sample |
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| CN114593971B true CN114593971B (en) | 2022-12-06 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0514890U (en) * | 1991-07-31 | 1993-02-26 | 住友金属工業株式会社 | Steel pipe test piece deployment device |
| CN101271048A (en) * | 2008-05-04 | 2008-09-24 | 天津钢管集团股份有限公司 | Small-caliber steel pipe lateral impact sample flattening method |
| CN201540225U (en) * | 2009-09-25 | 2010-08-04 | 上海宝钢工业检测公司 | Mould for flattening tensile sample of UOE welding tube |
| CN209014359U (en) * | 2018-10-09 | 2019-06-21 | 浙江金洲管道工业有限公司 | A kind of steel pipe sample pressing die |
| EP3816307A2 (en) * | 2019-10-30 | 2021-05-05 | Saey NV | Method for production of flat steel plates |
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2022
- 2022-03-28 CN CN202210311945.XA patent/CN114593971B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0514890U (en) * | 1991-07-31 | 1993-02-26 | 住友金属工業株式会社 | Steel pipe test piece deployment device |
| CN101271048A (en) * | 2008-05-04 | 2008-09-24 | 天津钢管集团股份有限公司 | Small-caliber steel pipe lateral impact sample flattening method |
| CN201540225U (en) * | 2009-09-25 | 2010-08-04 | 上海宝钢工业检测公司 | Mould for flattening tensile sample of UOE welding tube |
| CN209014359U (en) * | 2018-10-09 | 2019-06-21 | 浙江金洲管道工业有限公司 | A kind of steel pipe sample pressing die |
| EP3816307A2 (en) * | 2019-10-30 | 2021-05-05 | Saey NV | Method for production of flat steel plates |
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| CN114593971A (en) | 2022-06-07 |
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