CN103542214B - Heavy caliber high-strength pipe-line hot drawing threeway wall thickness computational methods - Google Patents

Heavy caliber high-strength pipe-line hot drawing threeway wall thickness computational methods Download PDF

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CN103542214B
CN103542214B CN201210243066.4A CN201210243066A CN103542214B CN 103542214 B CN103542214 B CN 103542214B CN 201210243066 A CN201210243066 A CN 201210243066A CN 103542214 B CN103542214 B CN 103542214B
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Prior art keywords
wall thickness
tee
strength
pipe
tee joint
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CN103542214A (en
Inventor
刘迎来
吴宏
齐丽华
王高峰
郭志梅
李云龙
王长安
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BEIJING LONGSHENG TAIKE OIL PIPE TECHNOLOGY Co Ltd
Pipe-Line Construction Project Manager Portion Of Petrochina Co Ltd
CNPC Tubular Goods Research Institute
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BEIJING LONGSHENG TAIKE OIL PIPE TECHNOLOGY Co Ltd
Pipe-Line Construction Project Manager Portion Of Petrochina Co Ltd
CNPC Tubular Goods Research Institute
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Priority to CN201210243066.4A priority Critical patent/CN103542214B/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L41/00Branching pipes; Joining pipes to walls
    • F16L41/02Branch units, e.g. made in one piece, welded, riveted
    • F16L41/021T- or cross-pieces

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)

Abstract

A kind of heavy caliber high-strength pipe-line hot drawing threeway wall thickness computational methods, the calculating of heavy caliber high-strength tee pipe fitting wall thickness, formula is as follows: equal tee supervisor wall thickness: tMain≥tP/K1 Reducer tee supervisor wall thickness: tMain≥tP/K2 Described heavy caliber high-strength tee pipe fitting wall thickness computing formula is applicable to be made the making requirement of all X70 and X80 level Hi-grade steel other heavy caliber hot drawing tee pipe fitting of type by hot drawing.The present invention is the threeway area reinforcement calculation analysis work that can avoid lengthy and tedious complexity by this threeway wall thickness computational methods based on yard steel pipe, result of calculation is used for determining threeway minimum wall thickness (MINI W.), realize tubing steel pipe to couple with the equal strength of threeway, meet oil, the natural gas pipeline projects construction demand to high-strength big-diameter threeway.

Description

Wall thickness calculation method for hot-drawing tee joint for large-caliber high-strength oil and gas transmission pipeline
Technical Field
The invention relates to the technical field of oil and gas transmission equipment, in particular to a wall thickness calculation method of a hot-drawing tee joint for a large-caliber high-strength oil and gas transmission pipeline.
Background
In the construction of long-distance oil and gas pipeline engineering, in order to meet the requirements of branch transportation, diversion, measurement and the like, site construction of station yards, valve chambers, gas compression stations and the like often needs a large amount of large-diameter pipe fittings such as elbows, tees and the like. For the three-way pipe fitting, due to the unique arc transition structure of the root parts of the branch pipe and the main pipe, the structural strength of the three-way pipe fitting strongly depends on the root curvature radius R and the shoulder wall thickness t of the branch pipe and the main pipe, the calculation and analysis of the opening reinforcing stress are very complex, and an accurate equation solution is difficult to solve. Although engineering technicians propose various reinforcement calculation formulas by combining specific manufacturing process methods and specific boundary conditions of the tee joint, the design methods of the hot-drawing tee joint recommended by domestic and foreign standards mainly comprise two types: one is a verification test method, which is reliable, but is not widely used due to high implementation cost; the second is area reinforcementThe calculation method is that1+A2+A3≥ARAs shown in figure 1, a large number of engineering practices show that the wall thickness of the tee determined according to the latter is quite conservative, not only is the production cost high, but also the technical difficulty is greatly increased, and the final results determined by the two methods deviate greatly, so that the design requirements of pipeline engineering construction on the large-caliber high-strength tee are difficult to meet well.
Disclosure of Invention
The invention aims to design a method for calculating the wall thickness of a hot-drawn tee joint for a large-caliber high-strength oil and gas conveying pipeline, and solves the problems.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a method for calculating the wall thickness of a hot-drawn tee for a large-caliber high-strength oil and gas conveying pipeline is disclosed, wherein the formula of the method for calculating the wall thickness of the large-caliber high-strength tee is as follows:
wall thickness of the main pipe of the equal-diameter tee: t is tMaster and slave≥tP/K1
The wall thickness of the main pipe of the reducing tee: t is tMaster and slave≥tP/K2
Wherein,
K1in the process of forming the equal-diameter tee joint, the end of the branch pipeThe deformation coefficient of the wall thickness of the part relative to the wall thickness of the blank pipe;
K2in the process of forming the reducing tee, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of a blank pipe is obtained;
tmaster and slave-main pipe wall thickness (mm);
tP-the wall thickness (mm) of the branch pipe connecting pipe,
p-design pressure (MPa);
d, connecting the outer diameter (mm) of the steel pipe;
σS-minimum yield strength (MPa) of the material;
phi-weld coefficient;
t is temperature reduction coefficient;
f is a design coefficient, and is selected according to design conditions.
Preferably, the wall thickness calculation formula of the large-caliber high-strength tee pipe fitting is suitable for the manufacturing requirements of all X70 and X80-grade high-steel-grade large-caliber hot drawing tee pipe fittings formed by hot drawing.
Preferably, the mechanical property test of the large-caliber tee pipe fitting formed by hot drawing must meet the requirements of relevant standards.
Preferably, the method also comprises the following steps of carrying out blasting test research on the three-way pipe fitting obtained through theoretical calculation, and verifying that the construction requirements of the oil and gas transmission pipeline are met.
Preferably, K is in the range of 0.545-0.565.
Preferably, K2The range is 0.65-0.75.
The so-called relevant standards in claim 3 of the present invention are national standards, industry standards and united states standards, which are self-explanatory to industry designers.
The invention provides a tee minimum wall thickness calculation analysis method based on a station pipe by combining the characteristics of a hot-drawing tee forming process on the basis of completing a tee design calculation example and tee verification test result analysis for a large-caliber high-strength oil and gas transmission pipeline. The method takes equal strength matching of the steel pipe and the pipe fitting as a criterion, skillfully solves the problem of complicated three-way stress analysis by means of the wall thickness deformation coefficient of the branch pipe which can be expected by the metal flow in the hot-drawing three-way forming process, and provides a convenient and feasible design calculation method for pipeline engineering designers.
The invention relates to a structural design of a steel butt welding hot-drawing tee joint, which effectively solves the problem of complicated tee joint design calculation by adopting a tee joint plastic forming main and branch pipe wall thickness correlation coefficient based on the size of a connecting steel pipe and is suitable for the design of a high-strength large-caliber tee joint for an oil and gas conveying pipeline.
The invention provides a method for calculating the wall thickness of a high-strength large-caliber tee joint connected with a known station pipe on the premise of determining the specification of the station steel pipe. The minimum wall thickness of the large-caliber high-strength tee can be conveniently calculated by using the method, and the tee designed and produced by the calculation method has the ultimate bearing capacity which can completely meet the strength matching design requirement of the steel pipe of the long-distance pipeline station and the tee.
The technical scheme of the invention comprises the following authentication process:
1) the theoretical basis of the calculation method is as follows:
the long-distance pipeline comprises a main pipeline, a station yard, a valve chamber, a gas compression station and the like, and is a closed system, and the station yard, the valve chamber and the gas compression station in the system are connected by station yard steel pipes, three-way pipes and other strength, which are basic requirements of pipeline design. That is, in a long-distance pipeline system, the steel pipe and the tee (main pipe, shell and branch pipe) should have the same bearing capacity.
2) The structural strength of the tee is mainly determined by the radius of curvature R of the branch pipe and main pipe transition region and its minimum wall thickness t. Given the specification of the tee joint, the primary stress of the transition area of the branch pipe and the main pipe of the tee joint can be effectively reduced by increasing the wall thickness of the tee joint shell, and the stress concentration coefficient of the area is reduced.
3) In the hot drawing tee joint forming process, high-temperature metal plastically flows and deforms in a tee joint die to have regularity, and the wall thickness (t) of a main pipeMaster and slave) Essentially the same as the blank pipe (without taking into account high temperature oxidation losses), wall thickness at the end of the branch pipe (t)Branch stand) The equant tee joint and the reducing tee joint respectively have a determined deformation coefficient (the wall thickness correlation coefficient of the plastic forming main branch pipe) K1、K2I.e. the wall thickness of the main pipe of the tee and the minimum wall thickness t of the branch pipeBranch minIn a certain proportional relationship.
Equal-diameter tee joint: t is tBranch min=K1.tMaster and slave
Reducing the tee joint: t is tBranch min=K2.tMaster and slave
4) The minimum bearing capacity of the three-way branch pipe is larger than or equal to the minimum bearing capacity of the connecting steel pipe
When the pipeline bears the internal pressure, the pressure of the fluid flowing through the tee joint is the same as that of the fluid flowing through the station pipe; minimum wall thickness t of tee branch pipe endBranch minWall thickness t of the pipe connecting itPThe relationship is as follows:
tbranch min≥tP
Equal-diameter tee joint: t is tMaster and slave≥tP/K1
Reducing the tee joint: t is tMaster and slave≥tP/K2
The minimum wall thickness of the main pipe of the tee joint can be obtained.
In the above formula:
K1and in the process of forming the equal-diameter tee joint, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of the blank pipe is obtained. According to experience K1Generally, 0.545-0.565 is selected;
K2and in the process of forming the reducing tee, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of the blank pipe is obtained. According to experience K2Generally, 0.65-0.75 is selected;
tmaster and slave-main pipe wall thickness (mm);
tmain min-main pipe minimum wall thickness (mm);
tP-the wall thickness (mm) of the branch pipe connecting pipe,
p-design pressure (MPa);
d, connecting the outer diameter (mm) of the steel pipe;
σS-minimum yield strength (MPa) of the material;
phi-weld coefficient;
t is temperature reduction coefficient;
f is the design coefficient, and is selected according to the design conditions (such as 0.5 for three types of regions and 0.4 for four types of regions).
The beneficial effects of the invention can be summarized as follows:
the invention aims to avoid the complicated three-way area reinforcement calculation and analysis work by using the method for calculating the wall thickness of the three-way based on the station steel pipe, and the calculation result is used for determining the minimum wall thickness of the three-way so as to realize equal-strength connection between the steel pipe of the pipeline system and the three-way.
2, the invention can meet the requirements of petroleum and natural gas pipeline engineering construction on the high-strength large-caliber tee joint.
Description of the drawings:
FIG. 1 is a schematic diagram of the calculation of the three-way area reinforcement.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
A hot drawing tee wall thickness calculation method for a large-caliber high-strength oil and gas transmission pipeline is characterized in that a calculation formula of the wall thickness of the large-caliber high-strength tee is as follows:
wall thickness of the main pipe of the equal-diameter tee: t is tMaster and slave≥tP/K1
The wall thickness of the main pipe of the reducing tee: t is tMaster and slave≥tP/K2
Wherein,
K1in the process of forming the equal-diameter tee joint, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of the blank pipe is in the range of 0.545-0.565;
K2in the process of forming the reducing tee, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of a blank pipe is in the range of 0.65-0.75;
tmaster and slave-main pipe wall thickness (mm);
tP-the wall thickness (mm) of the branch pipe connecting pipe,
p-design pressure (MPa);
d, connecting the outer diameter (mm) of the steel pipe;
σS-minimum yield strength (MPa) of the material;
phi-weld coefficient;
t is temperature reduction coefficient;
f is the design coefficient, and is selected according to the design conditions (such as 0.5 for three types of regions and 0.4 for four types of regions).
More preferably, the method further comprises the following steps of carrying out blasting test research on the tee joint obtained through theoretical calculation, and verifying that the construction requirements of the oil and gas transmission pipeline are met. The wall thickness calculation formula of the large-caliber high-strength tee joint is suitable for the manufacturing requirements of all X70 and X80-grade high-steel-grade and low-strength-grade large-caliber hot-drawing tee joints formed by hot drawing; the mechanical property test of the large-caliber tee joint formed by hot drawing must meet the requirements of relevant standards (national standard, industrial standard and American standard, and the relevant standards are self-evident to industrial designers).
Example 1: the design pressure of the tee joint is 12MPa, the material is an X80 tee joint, the wall thickness of a connecting station pipe is 12MPa, the design pressure of the connecting station pipe is 30.8mm, the material is X80, the minimum wall thickness of the tee joint is 78mm determined by adopting area reinforcement, the minimum wall thickness of the tee joint is 48-50 mm determined by adopting the calculation method, and the verification test result of the tee joint of the connecting steel pipe is carried out, so that the limit bearing internal pressure of the tee joint is 43-46 MPa.
Example 2: the design pressure of phi 1219mm multiplied by 1016mm is 12MPa, the material is an X80 tee joint, the design pressure of the wall thickness of the connecting station pipe is 26.2mm, 12MPa, the material is X80, the minimum wall thickness of the tee joint determined by adopting area reinforcement is 64 mm, the minimum wall thickness of the tee joint determined by adopting the calculation method is 44mm, and the verification test result of the tee joint of the connecting steel pipe is carried out, so that the ultimate bearing internal pressure of the tee joint is 43.8 MPa.
Example 3: the design pressure of the tee joint is 12MPa, the material is an X80 tee joint, the wall thickness of a connecting station pipe is 26.2mm, the design pressure of the tee joint is 12MPa, the material is X80, the minimum wall thickness of the tee joint determined by adopting area reinforcement is 52 mm, the minimum wall thickness of the tee joint determined by adopting the calculation method is 40mm, and the ultimate bearing internal pressure of the tee joint is 44.5MPa according to the verification test result of the connecting steel pipe tee joint.
TABLE 1 ultimate bearing pressure of steel pipe for key pipeline engineering
TABLE 2 statistics of test results of early-stage trial tee blasting in pipeline engineering
TABLE 3 statistics of trial-production tee-joint blasting test results using the calculation method
Table 1 shows the ultimate bearing pressure of steel pipes for pipeline engineering. As can be seen from the table, the actual burst pressure of the steel pipes for pipeline engineering with X70 and X80 transport phi 1219mm is 18.25-33.07 MPa. Table 2 shows the statistics of the results of the blasting tests of the tee test piece for a certain pipeline engineering produced by calculating the wall thickness of the large-diameter tee according to the traditional area reinforcement formula. And table 3 shows the statistical values of the results of the blasting tests of the large-caliber tee joint and the trial-produced tee joint according to the wall thickness of the large-caliber tee joint calculated by the method. As can be seen from the above table, according to the results in Table 3, the actual burst pressure of the phi 1219mm hot drawing equal-diameter and reducing tee pipe fittings is both greater than 40MPa and far greater than the limit burst pressure of the steel pipes connected with the same, and the use requirements are met.
The present invention has been described in detail with reference to the specific and preferred embodiments, but it should be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and any modifications, equivalents and the like, which are within the spirit and principle of the present invention, should be included in the scope of the present invention.

Claims (4)

1. A method for calculating the wall thickness of a hot-drawn tee for a large-caliber high-strength oil and gas transmission pipeline is characterized in that the formula for calculating the wall thickness of the large-caliber high-strength tee is as follows:
wall thickness of the main pipe of the equal-diameter tee: t is tMaster and slave≥tP/K1
The wall thickness of the main pipe of the reducing tee: t is tMaster and slave≥tP/K2
Wherein,
K1in the process of forming the equal-diameter tee joint, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of a blank pipe is obtained;
K2in the process of forming the reducing tee, the deformation coefficient of the wall thickness of the end part of the branch pipe relative to the wall thickness of a blank pipe is obtained;
tmaster and slave-main pipe wall thickness (mm);
tP-the wall thickness (mm) of the branch pipe connecting pipe,
p-design pressure (MPa);
d, connecting the outer diameter (mm) of the steel pipe;
σS-minimum yield strength (MPa) of the material;
phi-weld coefficient;
t is temperature reduction coefficient;
f is a design coefficient, which is selected according to design conditions;
K1the range is 0.545 to 0.565,
K2the range is 0.65-0.75.
2. The method for calculating the wall thickness of the hot-drawn tee joint for the large-caliber high-strength oil and gas transmission pipeline according to claim 1, wherein the calculation formula of the wall thickness of the large-caliber high-strength tee joint is suitable for requirements of all X80 steel-grade large-caliber hot-drawn tee joints formed by hot drawing.
3. The method for calculating the wall thickness of the hot-drawn tee joint for the large-caliber high-strength oil and gas transmission pipeline according to claim 2, wherein the mechanical property of the large-caliber tee joint formed by hot-drawing meets the requirement of X80 steel grade.
4. The method for calculating the wall thickness of the hot-drawn tee joint for the large-caliber high-strength oil and gas conveying pipeline according to claim 1, characterized by further comprising the following steps of carrying out blasting test research on the tee joint obtained through theoretical calculation, and carrying out X80 steel grade equal-diameter tee joints with the specifications of phi 1219X 1219 and the wall thickness of 48mm and 50 mm; the specification is phi 1219 is multiplied by 1016, the wall thickness is X80 steel grade reducing tee of 44 mm; the specification is phi 1219 is multiplied by 914, the wall thickness is 40mm and X80 steel grade reducing tee joint of 44 mm; the actual burst pressure after the burst test is more than 40MPa after the X80 steel grade reducing tee joint with the specification of phi 1219 multiplied by 813 and the wall thickness of 40mm is subjected to the burst test.
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