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GB/T 17186.2-2018: Calculation methods for the pipe flange joints -- Part 2: Calculation method satisfies leakage rate
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Calculation methods for the pipe flange joints -- Part 2: Calculation method satisfies leakage rate
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Basic data | Standard ID | GB/T 17186.2-2018 (GB/T17186.2-2018) | | Description (Translated English) | Calculation methods for the pipe flange joints -- Part 2: Calculation method satisfies leakage rate | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | J15 | | Classification of International Standard | 23.040.60 | | Word Count Estimation | 40,430 | | Date of Issue | 2018-05-14 | | Date of Implementation | 2018-12-01 | | Older Standard (superseded by this standard) | GB/T 17186-1997���� | | Regulation (derived from) | National Standards Announcement No. 6 of 2018 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 17186.2-2018: Calculation methods for the pipe flange joints -- Part 2: Calculation method satisfies leakage rate
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Calculation methods for the pipe flange joints--Part 2. Calculation method satisfies leakage rate
ICS 23.040.60
J15
National Standards of People's Republic of China
Partially replace GB/T 17186-1997
Pipe flange connection calculation method
Part 2. Calculation method based on leakage rate
Part 2.Calculationmethodsatisfiesleakagerate
Published on.2018-05-14
2018-12-01 implementation
State market supervision and administration
China National Standardization Administration issued
Content
Foreword III
Introduction IV
1 Scope 1
2 Normative references 1
3 Terms and Definitions 1
4 illustrations and symbols 2
5 General provisions 12
6 Calculation parameters 14
7 joint internal force 18
8 Allowable load rate check 22
Appendix A (informative) Assembly using a torque wrench 26
Appendix B (Normative Appendix) Use of the original creep factor gc 28
Appendix C (informative) Flange deflection 29
Appendix D (informative) Discreteness of bolt fastening methods 30
Appendix E (informative) Calculation order 31
Appendix F (informative) Limitation of gasket stress unevenness requirements 33
Appendix G (informative) Metric bolt size 34
Reference 36
Foreword
GB/T 17186 "Calculation method for pipe flange connection" is divided into two parts.
--- Part 1. Calculation method based on strength and stiffness;
--- Part 2. Calculation method based on leakage rate.
This part is the second part of GB/T 17186.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This part replaces part of the GB/T 17186-1997 "Method for Calculating the Connection Strength of Steel Pipe Flanges" (Chapters 1~3, 5)
Chapter), compared with GB/T 17186-1997, except for editorial changes, the main technical changes are as follows.
--- Revised the standard structure, the original standard includes two different flange calculation methods (method A and method B);
--- This part has modified and improved Method B;
--- Modified the gasket factor;
--- Modified the flange calculation parameters and calculation steps;
--- Increased joint internal force calculation;
--- Increased the allowable load ratio check.
--- Added Appendix A assembly using torque wrench, use of Appendix B original creep factor gc, Appendix C flange deflection, Appendix D
Discreteness of bolt fastening method, calculation sequence of Appendix E, limit requirement of uneven distribution of stress distribution of gasket F in Appendix F, Appendix G
Metric bolt size.
This standard also made the following editorial changes.
--- Modified the standard Chinese and English names.
This part was proposed by the China Machinery Industry Federation.
This part is under the jurisdiction of the National Pipeline Attachment Standardization Technical Committee (SAC/TC237).
This section drafted by. China Machine Productivity Promotion Center, East China University of Science and Technology, China Petroleum Engineering Construction Corporation East China Design Branch, China
Guotianchen Engineering Co., Ltd., China Energy Construction Group Guangdong Electric Power Design and Research Institute Co., Ltd., Chaoda Valve Group Co., Ltd.
Division, Zhejiang Guotai Xiaoxing Sealing Material Co., Ltd.
The main drafters of this section. Zhang Lanzhu, Feng Feng, Liu Hongfu, Li Junying, Liu Jian, Liu Jianxin, Wang Xiaodong, Qiu Xiaolai, Wu Yimin.
The previous versions of the standards replaced by this section are.
---GB/T 17186-1997.
Introduction
This section is another method of flange connection calculation, especially for the following occasions.
a) where it is mainly subjected to cyclic loading;
b) where it is necessary to monitor the bolt load during preloading;
c) where the external load (force or moment) has a significant impact;
d) Where leakage rate control is particularly important.
Pipe flange connection calculation method
Part 2. Calculation method based on leakage rate
1 Scope
This part of GB/T 17186 specifies the calculation method for the bolted joint with a gasketed round pipe flange.
This section is mainly applicable to the pipe flange of the PN series. Class flanges and non-standard flanges are also available for reference.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 9112 Steel Pipe Flange Types and Parameters
EN13555.2004 Gasket parameters and test methods for flanges and their joints and circular flange connection design rules with gaskets
(Flangesandtheirjoints-Gasketparametersandtestproceduresrelevanttothedesignrulesforgas-
Ketcircularflangeconnections)
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Integral flange integrallflange
Can be welded (eg with neck butt weld flange, see Figure 4 ~ Figure 7 or flat weld flange, see Figure 8 and Figure 11), or cast into one (integral casting)
Flange, type 21), connects the flange to the housing.
3.2
Blind flange flangeflange
Flat cover, see Figure 9.
3.3
Loose flange looseflange
A separate flange ring attached to the flange.
3.4
Cone neck hub
The axial extension of the flange ring is usually used to connect the flange ring to the housing, see Figures 4 and 5.
3.5
Cuffed colar
Adjacent to the loose flange, see Figure 10.
3.6
External load externalloads
Other external loads act on the joints on forces and/or moments such as pipe weight and thermal expansion.
3.7
Load condition loadcondition
A set of operating conditions that simultaneously apply a load, identified as I.
3.8
Installation condition assemblycondition
The load condition of the initial tightening bolt is identified as I=0.
3.9
Subsequent conditions
Load conditions after installation conditions, such as test conditions, operating conditions, various operating conditions during driving or parking, identified as I = 1, 2
3,
3.10
Flexibility
The reciprocal of stiffness (axial).
Note. The unit is millimeters per cow (mm/N).
3.11
Flexibility modulus
The reciprocal of the stiffness modulus, excluding the elastic constant of the material.
The axial compliance modulus is X, in millimeters per millimeter (1/mm); the rotational compliance modulus is Z, in millimeters per cubic.
(1/mm3).
4 illustrations and symbols
4.1 icon
Figures 1 through 12 show the symbols associated with the geometry parameters. Figure 1 to Figure 12 are only schematic diagrams, and all applicable versions are not listed.
The flange type of the calculation method.
The types of GB/T 9112 standard flanges correspond to the following.
Model 01 Figure 8
Type 02 Figure 10
Type 04 Figure 10
Type 05 Figure 9
Figure 07 Figure 10
Type 11 Figure 4
Type 12 Figure 11
Type 13 Figure 12
Type 21 Figure 4~ Figure 7
a) integral flange load and force arm b) non-integral flange load and arm
Figure 1 Load and force arm
a) Hex bolt b) Stud stud c) Screw-in bolt d) Thread
Description.
Le=lb-ls.
Figure 2 bolt
a) flat washer b) oval pad c) cone pad
d) octagonal pad e) oval pad f) O-pad
Figure 3 gasket
Description.
1---shell;
2---neck;
3---flange ring.
Figure 4 neck flange with butt weld to cylindrical housing (example 1)
Description.
1---shell;
2---neck;
3---flange ring.
Figure 5 neck flange with butt weld to cylindrical housing (example 2)
Description.
1---shell;
2---flange ring.
Figure 6 Flange welded to a conical shell
Description.
1---shell;
2---flange ring.
Figure 7 Flange welded to the spherical housing
Description.
1---shell;
2---flange ring.
Figure 8 plate flat welding flange
Description.
1---round plate;
2---flange ring.
Figure 9 blind flange
Description.
1---shell;
2---Flange;
3--- loose flange.
Figure 10 Loose flange with flange
Figure 11 neck welded flat flange
Figure 12 with neck threaded flange
4.2 Subscripts and special marks
4.2.1 Subscript
A ---Additional (FA, MA)
B ---bolt
C ---gasket creep (gc)
D --- equivalent cylinder for ultimate load calculation (cone neck connected shell)
E --- equivalent cylinder for flexibility calculation (cone neck connected shell)
F --- flange
G ---shield
H --- cone neck
I --- Identification of load conditions (take 0, 1, 2)
L --- loose flange
M --- moment
P --- pressure
Q --- Net axial force caused by pressure
R --- net axial force caused by external force
S --- shell, shear
T --- housing, modified
X --- weak section
Δ --- variation symbol
The actual size considered in the act calculation
Av --- average
c --- calculation
d --- design
e --- effective
Max---maximum
Min---minimum
Nom---nominal
Opt --- optimal
Ref quotes the size of 7.4 in EN13555.2004
Required for req
s --- non-threaded part of the bolt
t --- theory, torque, thread
0 --- Initial installation conditions (I=0, see subscript I)
4.2.2 Special marking
~---The upper part of the flange parameter symbol plus the ~ sign indicates the second flange in the joint, which may be different from the first flange type.
4.3 symbol
The following symbols are marked with square brackets when there are units, and not when there are no units.
AB --- effective bolt total cross-sectional area [mm2]
AF, AL --- total radial cross-sectional area of flange ring and loose flange (including bolt hole) [mm2], formula (5), formula (7),
Formula (8)
AGe, AGt --- effective area of the gasket, theoretical area of the gasket, [mm2], formula (39), formula (36)
C --- Calculate the coefficient of torque when calculating the bolt load ratio, formula (71)
EB, EF, EG, EL --- modulus of elasticity of each subscript component at its temperature [MPa]
FA --- additional axial external force [N], pull force >0, pressure < 0, see Figure 1
FB --- bolt force (sum of all bolts) [N]
FG ---shield force [N]
FGΔ --- Minimum gasket force [N] under installation conditions, to ensure that all loads are changed when entering the next working condition
Gasket force, type (51)
FQ --- axial force caused by fluid pressure [N], equation (43)
Force caused by FR ---FA and MA [N], equation (44)
I --- load condition identification, installation condition I = 0, followed by working conditions I = 1, 2, 3,
IB ---bolt polished rod [=
12×min
Plastic torsional modulus of [dBe;dBs)3] [mm3], equation (71)
Ks --- systematic error due to inaccuracy of the bolt fastening method
MA --- additional external torque [N·mm], see Figure 1
Mt --- bolt mounting torque [N·mm], see Appendix A
Mt, B --- bolt mounting torque Mt, the torque of the bolt polished rod [N·mm], formula (71),
Formula (A.8), formula (A.11)
NR --- The number of times to reinstall and retighten the joint during its service life, (67)
P ---fluid pressure [MPa]; internal pressure >0, external pressure < 0
PQR --- creep coefficient, ratio of gasket stress to initial gasket stress under load conditions
Q --- Average effective gasket compressive stress [MPa], Q=FG/AGe
QA --- Installation gasket stress [MPa] before unloading is necessary to determine QSmin(L)I under operating conditions.
Equation (49)
QSmin(L) --- The minimum gasket stress [MPa] required to achieve the seal level L during unloading,
(50)
Qmin(L) --- The minimum gasket stress (effective gasket area) required to achieve the seal level L during assembly is also
QA acceptable minimum value [MPa]
QSmax --- The maximum gasket that can be safely applied to the gasket at operating temperature without any damage
force. [MPa], formula (72a), formula (72b)
Qmax --- The maximum gasket that can be safely applied to the gasket at operating temperature without any damage
Force (according to the actual shape of the gasket in the flange bolt connection) [MPa], formula (72b), formula (72c)
QmaxY --- The maximum gasket that can be safely applied to the gasket at the operating temperature without any damage should be
Force (independent of the shape of the gasket) [MPa], formula (72a)
TB, TF, TG, TL --- temperature (average) [°C] or [K] of each subscript component, equation (45)
T0 --- Connector temperature [°C] or [K], (typically 20 ° C)
U --- axial displacement [mm], ΔU according to equation (45)
WF, WL, WX --- impedance of each subscript component or (and) section [N·mm], equation (74), equation (86), equation (88),
Formula (90)
XB, XG --- axial flexibility modulus of bolt/gasket [1/mm], formula (34), formula (72)
YG, YQ, YR --- Axial compliance of bolt joints, related to FG, FQ, FR, formula (46), formula (47), formula (48)
ZF, ZL --- Rotational flexibility modulus of flange and loose flange [mm3]. Equation (27), Equation (31), Equation (32)
B0 --- Loose flange chamfer (or rounded corner) width [mm], Figure 10, formula (15), and meet the following conditions.
D7min=d5 2×b0
bF, bL --- effective width of flange and loose flange [mm], formula (5)~ (8)
bGi, bGe, bGt --- Width (radial) of the spacer, temporary; effective; theory [mm], Table 1, Equation (35), Equation (38)
C1 ---shield type constant such as. c1 = 1/20 for fiber reinforced plate gasket; when no value is available c1
=0. Formula (72a), formula (72b)
cF, cM, cS --- correction factor, equation (20), equation (78), equation (79)
D0 --- flange ring inner diameter [mm], is also the outer diameter of the center of the blind flange (thickness e0), not greater than
The inner diameter of the gasket, see Figure 4~12
D1 --- average diameter of the cone neck, small end [mm], Figure 4, Figure 5, Figure 11, Figure 12
D2 --- average diameter of the cone neck, big end [mm], Figure 4, Figure 5, Figure 11, Figure 12
D3, d3e --- Bolt center circle diameter. actual; effective [mm]. Figure 4~12
D4 --- flange outer diameter [mm], Figure 4 ~ Figure 12
D5, d5t, d5e --- Bolt hole diameter. through hole; blind hole; effective [mm]. Figure 4~12
D6 --- loose flange inner diameter [mm], Figure 10, Figure 12
D7 --- Diameter [mm] at the interaction between the flange and the flange, Figure 1, Equation (15), Equation (41)
D8 --- Flange outer diameter [mm], Figure 10
D9 --- blind plate flange center opening diameter [mm], Figure 9
dB0, dBe, dBs --- Bolt diameter. Nominal diameter; Effective diameter; Bolt polished rod diameter [mm]. Figure 2, Table G.1
dB2, dB3 --- thread pitch diameter; thread root diameter [mm]. figure 2
dGe, dGt ---shim diameter. effective; theory. Figure 3, Table 1
dG1, dG2 --- gasket theoretical contact surface inside and outside diameter [mm], Figure 3
dE, dF, dL, dS, dX --- the average diameter of each subscript member or section [mm], formula (5) ~ formula (8), formula (10) ~ formula (12),
Figure 4~12
E0 --- in the range of the diameter d0, the wall thickness of the center of the blind flange [mm], Figure 9
E1 --- minimum wall thickness [mm] of the small end of the cone neck, Figure 4, Figure 5, Figure 11, Figure 12
E2 --- cone neck large end wall thickness [mm], Figure 4, Figure 5, Figure 11, Figure 12
eD, eE --- equivalent cylinder wall thickness [mm] for ultimate load calculation, for compliance calculation, equation (9), equation (11),
(12), formula (75)
eF, eL --- flange and loose flange effective axial thickness [mm], formula (5) ~ (8)
eFb --- flange diameter [mm] at diameter d3 (bolt position), equation (3)
eFt --- thickness of the flange ring [mm] at the diameter dGe (shield force position), related to thermal expansion, formula (45)
eG ---shield thickness, [mm], Figure 3
eP, eQ --- flange thickness, radial pressure is eP, no radial force is eF, Figure 4 ~ Figure 12, eP eQ = eF
eS --- thickness of the connected shell [mm], Figure 4 ~ Figure 8, Figure 10 ~ Figure 12
eX --- flange thickness of the weak part [mm], Figure 9
fB, fE, fF, fL, fS --- the nominal design stress of each subscript component at the design temperature (°C or K), and the pressure vessel specification
The meaning and usage are the same.
Gc ---EN1591-1. The creep coefficient of the gasket in the.2001 version, instead of PQR, if using gc,
The corresponding calculation method is shown in Appendix B.
hG,hH,hL ---force arm [mm], Figure 1, formula (14), formula (16)
hP, hQ, hR, hS, hT --- force arm correction [mm], formula (13), equation (21)~ equation (24), equation (29), equation (30)
jM, jS --- torque mark number, shear force (1 or 1), formula (80)
kQ,kR,kM,kS ---correction coefficient, equation (25), equation (26), equation (81)
lB, lS --- bolt axial dimension [mm], Figure 2, formula (34)
Le ---le=lB-lS
lH --- cone neck length, Figure 4, Figure 5, Figure 11, Figure 12, Equation (9), Equation (75)
nB --- the number of bolts, formula (1), formula (4), formula (33), formula (34), formula (56a), formula (56b), formula (58a),
(58b), formula (A.1), formula (A.2), formula (A.8), formula (A.9), (formula A.10)
pB ---bolt spacing [mm], type 1
Pt ---pitch, table B.1
R0, r1 ---radius [mm], Figure 4, Figure 10
R2 --- Curvature radius [mm] of the gasket section, Figure 3
ΔU --- axial expansion difference, equation (45)
θF, θL --- deflection angle (rad) of flange or loose flange caused by moment, Appendix C
Ψ --- Radial force generated flange ring load specific load rate, formula (82)
特殊Z --- Ψ special value, formula (74), table 2
ΦB, ΦF, ΦG, ΦL, ΦX---load ratio of each subscript component or (and) section under various load conditions, formula (71), equation (72c),
Formula (73), Formula (85), Formula (87), Formula (89), Formula (91)
Φmax --- maximum allowable load ratio, formula (70)
αB,αF,αG,αL --- the coefficient of thermal expansion of each subscript component, the average of T0 and TB, TF, TG, TL, TS[K-1]
β, γ, δ, v, κ, λ, χ --- intermediate variables, formula (9), formula (17), formula (18), formula (19), formula (41), formula (70), (75), formula (77)
Ε1 , ε1 -- --- The dispersion of the initial bolt load of a single bolt, higher than the nominal value, lower than the nominal value, see Appendix D
ε , ε - --- The divergence of the total load of all bolts. higher than the nominal value; lower than the nominal value. Formula (60), formula (61)
π --- constant (= 3.141593)
ρ --- formula (28) gives the diameter ratio
φG --- the inclination of the sealing surface [rad or (°)], Figure 3, Table 2
φS --- the inclination of the connected shell wall [rad or (°)], Figure 6, Figure 7
5 General regulations
5.1 Requirements for use of calculation methods
This calculation method can be used to check the flange design instead of other methods, such as.
---Special test;
--- Actual verification;
--- PN series standard flanges used under permitted conditions.
See Appendix E for the calculation sequence.
5.2 Applicable parameter limits
5.2.1 Geometric shape
This calculation method applies to flanges of the following shapes.
---Flange section is the same or similar shape as Figure 4~12;
---4 or more uniform bolts of the same specification;
--- After loading, the cross section and shape of the gasket are consistent with any of the shapes shown in Figure 3;
---Flange size meets the following conditions.
a) 0.2 ≤ bF/eF ≤ 5.0; 0.2 ≤ bL/eL ≤ 5.0
b) eF ≤ max{e2; dB0; pB ×
3(0.010.10)×pB/bF}
c) cosφ≥
1 0.01dS/eS
Note 1. For the flange of the loose flange, it is not necessary to meet bF/eF ≤ 5.0.
Note 2. eF ≥ pB ×
3 (0.010.10) × pB/bF is used to limit the non-uniformity of the gasket stress due to the bolt spacing. 0.01 and 0.10 respectively
Soft (non-metallic) and hard (metal) sealed. See Appendix F.
It should be noted that due to dimensional tolerances and corrosion effects, this calculation method does not apply to flanges of the following shapes.
--- Intrinsically non-axisymmetric flanges, such as split loose flanges, with reinforced flanges.
--- The inner side (or) of the flange and the gasket, metal and metal directly between the inner and/or outer sides of the flange and the center circle of the bolt
Indirect contact flange connection.
5.2.2 Materials
This calculation method does not specify the allowable stress values for materials and can be obtained by relevant standards, such as GB 150.2 or related industrial piping specifications.
Bolt design stress can be determined based on the flange and housing. The gasket is modeled as a material with elastic-plastic behavior.
Note. For gaskets made of compressible materials that allow a large amount of deformation (such as flat gaskets with rubber as the main component), this calculation method will get too much.
Conservative calculations (ie, the required bolt load is too high, the allowable fluid medium pressure is too small, the flange thickness is too thick, etc.) because this calculation method does not
Consider these properties of the gasket.
5.2.3 Load
This calculation method is used for the following types of loads.
--- Fluid pressure. internal or external;
--- External load. axial force and bending moment;
--- Axial expansion of flanges, bolts and gaskets, especially by thermal effects.
5.2.4 Mechanical model
5.2.4.1 This calculation method is based on the following mechanical model.
a) The shape of the flange and gasket are axisymmetric. Small deviations due to the limitation of the number of bolts are allowed. Not allowed for splitting
Loose flange and oval flange.
b) The radial section of the flange ring is not deformed. Only the circumferential stress and strain of the ring are considered, ignoring the radial and axial stresses and strains.
This assumption is necessary to comply with 5.2.1a).
c) The flange ring is connected to the cylindrical housing. The cone neck can be regarded as an equivalent cylindrical shell that is converted by wall thickness, and the cylindrical shell and cone
The elastic and plastic behavior of the shell is different. The calculated wall thickness is between the actual maximum and minimum wall thickness. The conical shell and the spherical shell can
Considering an equivalent cylindrical shell having the same wall thickness, the difference between the conical shell and the spherical shell and the cylindrical shell is considered in the calculation formula.
This assumption is necessary to comply with 5.2.1.c).
At the junction of the flange ring and the housing, the continuity of the radial displacement and the deflection angle should be considered in the calculation.
d) The gasket and flange are in contact on the calculated annular area. The effective width of the spacer (radial) bGe may be less than the actual width of the spacer. Gasket
The calculation of the effective width is based on the installation conditions (I = 0) and is assumed to be unchanged under the subsequent load conditions (I = 1, 2, 3,).
The bGe is calculated to include the elastic deflection of the flange and the elastic and plastic deformation of the gasket under installation conditions.
e) The modulus of elasticity of the gasket increases as the compressive stress Q of the gasket increases. For some gasket stress levels, the modulus of elasticity is
The elastic-plastic secant modulus measured from 100% of the stress level unloaded to 33%. This calculation method uses the highest installation time
Stress (Q).
f) The creep of the gasket during compression can be approximated by the creep coefficient PQR.
g) Consider axial thermal deformation and mechanical deformation of flanges, gaskets and bolts.
h) The load on the flange joint is axisymmetric. For any non-axisymmetric bending moment, use an axially symmetric equivalent axial force according to equation (44)
instead.
i) Changes in load under different operating conditions can cause changes in bolt and gasket stress. The calculation should take into account the elastic changes of all components
shape. To ensure sealing, the required initial assembly force (see 7.5) should be calculated to ensure that the required gasket is achieved under all operating conditions.
Force (see 7.4, 7.6).
j) The verification of the load limit value is based on the ultimate load of each component, which prevents excessive deformation. Gasket limit value
In Qmax) is an approximation.
5.2.4.2 The model does not consider the following factors.
a) Bending stiffness and bending strength of the bolt. However, the tensile stiffness of the bolt (approximate) contains the threaded portion of the bolt and the nut or snail
Deformation of the contact portion of the pit [see equation (34)].
b) Creep of flanges and bolts.
c) The radial deformation of the gasket is uneven (this simplification has no effect on the same type of flange).
d) Fatigue verification (not generally considered in the relevant specifications of this calculation method).
e) External torque and external shear forces, such as those caused by piping.
6 calculation parameters
6.1 Flange parameters
6.1.1 General
The calculation formula in 6.1 applies to each flange and flange of a flange joint and a flanged flange joint...
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