Some standard content:
JB | | tt | 2003-03-01 Implementation
Released by the National Economic and Trade Commission
Foreword
Scope
Normative reference documents
General provisions·
Materials
Internal pressure cylinder and internal pressure spherical shell
External pressure cylinder and external pressure spherical shell
Head
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9||tt ||Openings and opening reinforcements
Latent blue
.10 Manufacturing, inspection and acceptance
Xie Lu A (Normative Appendix)
Appendix B (Normative Appendix )
Appendix C (Normative Appendix)
Appendix·D (Normative Appendix)
Appendix E (Informative Appendix)
Appendix F (Informative Appendix)| |tt||Appendix G (informative appendix)
Titanium container welder examination rules
Titanium container welding process evaluation
item
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titanium container Mechanical properties inspection of product welding test plates Titanium and titanium alloy welding wires for pressure vessels
Titanium vessel welding process regulations
Strength and some mechanical, physical and process performance structures of titanium and titanium alloys at various temperatures Design
JB/T 47452002
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156
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JB/T4745—2002
Foreword
This standard is based on national pressure The 1998 standard preparation plan of the Container Standardization Technical Committee was formulated with reference to the corresponding standard contents of advanced industrial countries and in accordance with the production practice and quality control indicators of titanium welded vessels in China. This standard includes 10 main chapters and 7 appendices. Appendix A, Appendix B, Appendix C and Appendix D of this standard are normative appendices. Appendix E, Appendix F, and Appendix G of this standard are informative appendices. This standard is proposed and administered by the National Pressure Vessel Standardization Technical Committee. This standard is organized and drafted by the Secretariat of the National Pressure Vessel Standardization Technical Committee. The main drafters of this standard are: Huang Jiahu, Sang Rubao, and Wang Ronggui. The units and personnel participating in the drafting of this standard are: Shou Binan, Yang Guoyi (Economic and Technical Research Institute of Sinopec Group Corporation), Li Shiyu (Beijing Petrochemical Engineering Company of Sinopec Group Corporation), Yang Jinxiang (Baoji Nonferrous Metal Processing Plant), Deng Guishun (Nanjing Baose Titanium Co., Ltd.), Xu Minglin (China Wuhuan Chemical Engineering Company), Wang Jubin, Chen Shuyi (Hefei General Machinery Research Institute). This standard is interpreted by the National Pressure Vessel Standardization Technical Committee. 154
Scope
Titanium welded vessels
JB/T 4745~2002bzxz.net
This standard specifies titanium welded vessels (including shells and other components that are all titanium, Design, manufacturing, inspection and acceptance requirements for containers made of titanium-lined and titanium composite steel plates).
1.1 This standard applies to titanium welded atmospheric pressure vessels and titanium welded pressure vessels with design pressures not greater than 35MPa. : 1.2: The applicable design temperature range of this standard is determined according to the allowable use temperature of titanium materials and titanium composite plates. The applicable design temperature range for titanium-lined vessels also takes into account the difference in linear expansion coefficients between titanium and steel. : 1.3 This standard does not apply to the following types of containers: a) containers directly heated by flames;
containers in nuclear energy installations:
b)
as rotating or reciprocating motion Pressure chambers of components of moving machinery and equipment (such as centrifugal pump shells, reciprocating pump cylinders, compressor cylinders, refrigerator cylinders, blower shells, centrifuge drums, etc.); frequently transported Container;
d)
The inner diameter (for non-circular cross-section, refers to the width, height or diagonal, such as the diagonal of a rectangle and the long axis of a circle) is less than 150mm e| |tt||Container:
f) Container for fatigue analysis.
1.4 The calculation method for each component of the container listed in this standard is applicable to all-titanium containers. The steel parts of containers lined with titanium and titanium composite steel plates are designed according to the corresponding steel container standards. The titanium layer is generally not included in the calculation. strength. ·1.5 For pressure components whose structural dimensions cannot be determined using this standard, the following methods are allowed to be designed, but must be evaluated and approved by the National Pressure Vessel Standardization Technical Committee.
Stress analysis including finite element method; confirmatory experimental analysis (such as experimental stress analysis, confirmatory hydraulic test); - comparative empirical design using comparable structures that have been put into use. Normative reference documents
The provisions in the following documents become provisions of this standard through reference in this standard. For dated reference documents, all subsequent amendments (excluding corrigenda) or revisions do not apply to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. Version. For undated referenced documents, the latest edition applies to this standard. GB150—1998 Steel pressure vessels
GB/T196 Basic dimensions of ordinary threads (diameter 1mm~600mm) GB/T197 Tolerances and fits of ordinary threads (diameter 1mm~355mm) GB/T228 Metal tensile test methods||tt ||GB/T232 Bending test method for metal materials
GB/T1804 General tolerances Tolerances of linear and angular dimensions without tolerance GB/T29651996 Titanium and titanium alloy bars
GB/T3620.1 Titanium And titanium alloy grades and chemical composition GB/T3621—1994
Titanium and titanium alloy plates
155
JB/T 4745-2002
Titanium and titanium alloy wire| |tt||GB/T3623—1998
GB/T 3624—1995
Titanium and titanium alloy tubes
GB/T3625—1995
Heat exchangers and condensation Titanium and titanium alloy tubes for appliances GB/T4698
Chemical analysis method for titanium sponge, titanium and titanium alloy pure
GB/T4842
GB/T5168
GB/T5193| |tt||Two-phase titanium alloy high and low magnification structure inspection methods Titanium and titanium alloy processing products Ultrasonic flaw detection methods Titanium and titanium alloy castings
GB/T 6614—
1994
Titanium and Packaging, transportation and storage of titanium alloy processed products GB/T8180
GB/T 8546—1987
Titanium-stainless steel composite plate
GB/T 8547—1987
Titanium-steel composite plate
GB12337 Steel spherical storage tank
Ultrasonic inspection method for titanium and titanium alloy pipes GB/T12969.1
GB/T12969.2 Eddy current test method for titanium and titanium alloy pipes GB/T13149 Technical conditions for welding of titanium and titanium alloy composite steel plates CB/T14845-1993 Titanium plates for plate heat exchangers GB/T15073
Grades and chemical compositions of cast titanium and titanium alloys GB/T16598—1996 Titanium and titanium alloy cakes and rings Classification and technical conditions for pressure vessel flanges
JB/T4700
JB/T4701
JB/T4 702
JB/T4703
Type A flat welding flange
Type B flat welding flange
Long neck butt welding flange
JB/T4704
Non-metallic soft gasket
JB/T4705
Spiral wound gasket
JB/T4706
JB/T4707
JB4708
Metal clad gasket
Equal length double Head stud
Welding procedure assessment for steel pressure vessels
JB/T4709
JB4710
JB4730
Welding code for steel pressure vessels
Steel tower vessels
Non-destructive testing of pressure vessels
JB/T4735
Steel welded atmospheric pressure vessels
JB/T4744
Force of welding test plates for steel pressure vessel products Performance inspection of steel pressure vessel heads
JB/T47464
Safety technical supervision regulations for pressure vessels (issued by the former State Administration of Quality and Technical Supervision in 1999) Examination and management rules for welders of boiler pressure vessels and pressure pipes (issued by the General Administration of Quality Supervision, Inspection and Quarantine in 2002) 3 General provisions
3.1 In addition to complying with the provisions of this standard, the design, manufacture, inspection and acceptance of vessels shall also comply with relevant laws, regulations and rules promulgated by the state.
3.2 Qualifications and responsibilities
3.2.1 Qualifications
3.2.1.1 The design and manufacturing units of vessels shall have a sound quality management system. The pressure vessel design unit shall hold a pressure vessel design unit approval letter, and the manufacturing unit shall hold a pressure vessel manufacturing license. 156
.3.2.1.2 The design and manufacture of pressure vessels shall be subject to the supervision of the pressure vessel safety supervision agency. 3.2.2 Responsibilities
: 3.2.2.1 Responsibilities of the design unit
3.2.2.1.1 The design unit shall be responsible for the correctness and completeness of the design documents. 1.3.2.2.1.2 The design documents of the container shall at least include the design calculation and design drawings. 43.2.2.1.3 The general design drawing of the pressure vessel shall be stamped with the pressure vessel design qualification seal. 3.2.2.2 Responsibilities of the manufacturing unit
JB/T4745-2002
3.2.2.2.1 The manufacturing unit shall manufacture in accordance with the requirements of the design drawings. If the original design needs to be modified, the approval of the original design unit shall be obtained.
3.2.2.2.2 During the manufacturing process and after completion of the container, the inspection department of the manufacturing unit shall conduct various specific inspections and tests on the container in accordance with the provisions of this standard and drawings, submit an inspection report, and be responsible for the correctness and completeness of the report. 3.2.2.2.3 The manufacturing unit shall have at least the following technical documents for reference for each container product it manufactures, and the technical documents shall be kept for at least 7 years:
manufacturing process drawings or manufacturing process cards;
a)
b) material certification documents and material lists;
welding process and heat treatment process records of the container;
d)
records of items allowed for manufacturing selection in the standards: inspection records during the container manufacturing process and after completion;
|original design drawings and completion drawings of the container.
Note: If the original design drawing is modified to form a finished drawing, it is deemed to have the "design drawing and finished drawing\" treatment.-3.2.2.2.4 After the manufacturer obtains the inspection agency to confirm that the quality of the container meets the requirements of this standard and drawings, it shall fill in the product quality certificate and deliver it to the user.
3.3 Scope of containers
The scope of containers specified in this standard refers to the shell and the pressure-bearing parts connected to it as a whole, and is within the scope of 3.3.1~3.3.4. The connection between the container and the external pipeline includes:
3.3.13
a)
The first circumferential joint bevel end face of the welded connection; the first threaded joint end face of the threaded connection; b)
c)
The first flange seal of the flange connection Cover; d) The first sealing surface connected by a special connector or pipe fitting. 3.3.2 Pressure-bearing heads, flat covers and their fasteners for connecting pipes, manholes, handholes, etc. -3.3.3 Welded joints between non-pressure components and pressure components. Components other than joints, such as reinforcement rings, supports, skirts, etc., shall comply with the provisions of this standard or corresponding standards.
3.3.4 The overpressure relief device directly connected to the container shall comply with the requirements of Appendix B of GB150-1998. Accessories such as instruments connected to the container shall comply with the provisions of relevant standards. 3.4 Terms and Definitions
The following terms and definitions apply to this standard. 3.4.1
Pressurepressure
Unless otherwise specified, pressure refers to gauge pressure. 3.4.2
Work Working pressure
workingpressure
The highest pressure that may be reached at the top of the container under normal working conditions. 157
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3.4.3
Design pressuredesignpressure
The highest pressure set at the top of the container, together with the corresponding design temperature as the design load condition, its value shall not be lower than the working pressure. 3.4.4
Calculating pressurecaleulatingpressure
The pressure used to determine the thickness of the component at the corresponding design temperature, including the static pressure of the liquid column. When the static pressure of the liquid column borne by the component is less than 5% of the design pressure, it can be ignored. 3.4.5
Test pressuretestpressure
Pressure at the top of the vessel during the pressure test. 3.4.6
Design temperaturedesigntemperature
The metal temperature of the component set under normal working conditions of the vessel (the average temperature along the metal cross section of the component). The design temperature and design pressure are used together as the design load conditions.
3.4.7
Test humiditytesttemperature
The metal temperature of the shell during the pressure test. 3.4.8
Calculated thickness
calculatedthickmess
The thickness calculated according to the formula of each chapter. If necessary, the thickness required for other loads should also be taken into account (see 3.5.4). 3.4.9
Design thicknessdesignthickness
The sum of the calculated thickness and the corrosion allowance.
3.4.10
Nominal thickness
Fnorminalthickness
Design thickness plus negative deviation of titanium thickness rounded up to the thickness of titanium standard specifications. That is, the thickness marked on the drawing. 3.4.11
Effective thickness
Nominal thickness minus corrosion allowance and negative deviation of titanium thickness. 3.4.12
fminimum formed thickness
Minimum formed thickness
The thickness obtained by adding the greater of the calculated thickness and the minimum thickness of the component specified in this standard to the corrosion allowance. The nominal thickness and the minimum formed thickness (in brackets) should be indicated on the drawing at the same time. 3.4.13
permanentsetstress
Specified residual elongation stress
The stress when the residual elongation of the gauge length of the tensile specimen reaches the specified percentage of the original gauge length after the tensile force is removed. The symbol for this stress should be accompanied by a corner note, for example, ea represents the stress when the specified residual elongation reaches 0.2%. Note: In the design and manufacture of containers, it is allowed to use the value of the service strength 0.2 instead of the specified residual elongation stress 0.2. 3.5 General provisions for design
3.5.1 When determining the design pressure, consideration should be given to: a) When an overpressure relief device is installed on the vessel, the design pressure should be determined in accordance with the provisions of Appendix B of GB150-1998; b) When determining the design pressure of the external pressure vessel, the design pressure during normal operation should be considered. The maximum internal and external pressure difference that may occur under the circumstances; 158
1
c)
JB/T4745—2002
When determining the shell thickness of the vacuum vessel, the design pressure Consider it as a container withstanding external pressure. When a safety control device (such as a vacuum relief valve) is installed, the design pressure shall be the smaller of 1.25 times the maximum internal and external pressure difference and 0.1MPa; when there is no safety control device, the design pressure shall be 0.1MPa; ||tt| |d) For vessels composed of two or more pressure chambers, such as jacketed vessels, when determining the design pressure, the maximum pressure difference between each chamber should be considered.
3.5.2 When determining the design temperature, consideration should be given to: a)
The design temperature should not be lower than the maximum temperature that the component metal may reach in the working state. For metal temperatures below 0°C, the design temperature should not be higher than the lowest possible temperature of the component metal; when the metal temperatures of each part of the container are different under working conditions, the design temperature of each part can be set separately; b) ||tt ||The metal temperature of the component can be obtained by heat transfer calculation, or measured on a used container of the same working condition, or determined according to the internal medium temperature c)
Determined:
d) at any time In this case, the surface temperature of the component metal should not exceed the allowable service temperature of the material. 3.5.3 For vessels with different working conditions, they should be designed according to the most severe working condition, and the pressure and temperature values ??of each working condition should be indicated in the drawings or corresponding technical documents.
3.5.4 Loads
The following loads should be considered when designing:
a) internal pressure, external pressure or maximum pressure difference;
b) hydrostatic pressure.
When necessary, the following loads should also be considered:
The self-weight of the container (including internal parts and fillers, etc.), and the gravity load of the contents under normal working conditions or pressure test conditions c)|| tt||Load;
Gravity load of ancillary equipment and insulation materials, linings, pipes, escalators, platforms, etc.; d)
e)
f)
g)
h)
i)
Wind load, earthquake force, snow load;
Reaction of bearings, base rings, lugs and other types of supports Force; force connecting pipes and other components: force caused by temperature gradient or different thermal expansion; impact load including sharp fluctuations in pressure: impact reaction force, such as reaction force caused by fluid impact: k) ||tt| |Forces during transportation or hoisting.
3.5.5 Additional thickness
The additional thickness is determined according to formula (3-1):
C = Gi + Cz
Where: ||tt| |C - additional thickness, mm;
C, - negative deviation of titanium thickness, according to 3.5.5.1.mm; C - corrosion allowance, according to 3.5.5.2, mm. 3.5.5.1 Negative thickness deviation of titanium material
(3-1)
The negative thickness deviation of titanium plate or titanium tube shall be in accordance with the provisions of titanium material standards. When the negative deviation of the thickness of the titanium material is not greater than 0.25mm and does not exceed 6% of the nominal thickness, the negative deviation can be ignored. 3.5.5.2 Corrosion margin
In order to prevent the thickness of container components from weakening and thinning due to corrosion and mechanical wear, the corrosion margin should be considered. The specific provisions are as follows: a) For components with corrosion or wear, the corrosion margin should be based on the expected The corrosion margin is determined based on the vessel life and the corrosion rate of the medium on the metal material; 159
JB/T4745—2002
b) When the various components of the container are corroded to different degrees, different corrosion margins can be used quantity. 3.5.6 The minimum thickness of the shell after processing and forming, excluding corrosion allowance: a) cylinder 2mm;
b) other shell components according to relevant regulations.
3.5.7 Leak detection holes and leak detection structures should generally be provided between the titanium lining layer and the base layer of the pressure vessel and between the welded joint of the composite plate and the base layer. 3.6 Allowable stress
3.6.1 The allowable stress of the materials used in this standard is selected according to Chapter 4. The basis for determining the allowable stress of titanium materials is based on Table 3-1. Table 3-1 Basis for determining allowable stress
Allowable stress, MPs
(take the minimum value among the following values)
most tube
Note:| |tt||The lower limit of the standard tensile strength of titanium materials at room temperature, MPa; gi - the tensile strength of titanium materials at design temperature, MPa; product (average)
1.5||tt| |—The lower limit of the standard residual elongation stress of titanium materials at room temperature, MPa;ce2—The specified residual elongation stress of titanium materials at design temperature, MPa;s. (Average) - the average durability strength of titanium materials after 100,000 hours of fracture at the design temperature, MPa;. —The deformation limit of titanium material is 1% after 100,000 hours at the design temperature. When the MPa3.6.2 design temperature is lower than 20°C, the allowable stress at 20°C is taken. 3.6.3 Allowable axial compressive stress
The allowable axial compressive stress of a circle or a pipe shall be the smaller of the following two values: the allowable stress value of the material at the design temperature (see Chapter 4) And the B value obtained according to the following steps:
a) Calculate the coefficient A according to formula (3-2):
0.0948
A
R.
Where:
R. —Outer radius of a circle or tube, mm;. —The effective thickness of the circle or tube, mm (32)
b) According to the material, check Figure 6-3~Figure 6-8. If the A value falls to the right of the material line at the design temperature, then the This point moves vertically upward and intersects with the material line at the design temperature (interpolation method is used for the intermediate temperature), and then moves horizontally to the left after this intersection point to obtain the coefficient B (MPa): If the coefficient A falls to the left of the material line at the design temperature square, then calculate the B value according to formula (3-3): 2
AE
where:
E——The elastic modulus of the material at the design temperature, MPa. 3.7 Welding joint coefficient
The welding joint coefficient should be determined according to the welding joint type of the pressure component and the length ratio of the non-destructive test. a) Double-sided welded butt joints and full-penetration butt joints equivalent to double-sided welding: 100% non-destructive testing = 0.95
local non-destructive testing$=0.85
160
+( 3-3)
5 Additional thickness
The additional thickness is determined according to formula (3-1):
C = Gi + Cz
Where:
C-Thickness additional amount, mm;
C, - negative deviation of titanium thickness, according to 3.5.5.1.mm; C - corrosion allowance, according to 3.5.5.2, mm. 3.5.5.1 Negative thickness deviation of titanium material
(3-1)
The negative thickness deviation of titanium plate or titanium tube shall be in accordance with the provisions of titanium material standards. When the negative deviation of the thickness of the titanium material is not greater than 0.25mm and does not exceed 6% of the nominal thickness, the negative deviation can be ignored. 3.5.5.2 Corrosion margin
In order to prevent the thickness of container components from weakening and thinning due to corrosion and mechanical wear, the corrosion margin should be considered. The specific provisions are as follows: a) For components with corrosion or wear, the corrosion margin should be based on the expected The corrosion margin is determined based on the vessel life and the corrosion rate of the medium on the metal material; 159
JB/T4745—2002
b) When the various components of the container are corroded to different degrees, different corrosion margins can be used quantity. 3.5.6 The minimum thickness of the shell after processing and forming, excluding corrosion allowance: a) cylinder 2mm;
b) other shell components according to relevant regulations.
3.5.7 Leak detection holes and leak detection structures should generally be provided between the titanium lining layer and the base layer of the pressure vessel and between the welded joint of the composite plate and the base layer. 3.6 Allowable stress
3.6.1 The allowable stress of the materials used in this standard is selected according to Chapter 4. The basis for determining the allowable stress of titanium materials is based on Table 3-1. Table 3-1 Basis for determining allowable stress
Allowable stress, MPs
(take the minimum value among the following values)
most tube
Note:| |tt||The lower limit of the standard tensile strength of titanium materials at room temperature, MPa; gi - the tensile strength of titanium materials at design temperature, MPa; product (average)
1.5||tt| |—The lower limit of the standard residual elongation stress of titanium materials at room temperature, MPa;ce2—The specified residual elongation stress of titanium materials at design temperature, MPa;s. (Average) - the average durability strength of titanium materials after 100,000 hours of fracture at the design temperature, MPa;. —The deformation limit of titanium material is 1% after 100,000 hours at the design temperature. When the MPa3.6.2 design temperature is lower than 20°C, the allowable stress at 20°C is taken. 3.6.3 Allowable axial compressive stress
The allowable axial compressive stress of a circle or a pipe shall be the smaller of the following two values: the allowable stress value of the material at the design temperature (see Chapter 4) And the B value obtained according to the following steps:
a) Calculate the coefficient A according to formula (3-2):
0.0948
A
R.
Where:
R. —Outer radius of a circle or tube, mm;. —The effective thickness of the circle or tube, mm (32)
b) According to the material, check Figure 6-3~Figure 6-8. If the A value falls to the right of the material line at the design temperature, then the This point moves up vertically and intersects the material line at the design temperature (interpolation method is used for the intermediate temperature), and then moves horizontally to the left after this intersection point to obtain the coefficient B (MPa): If the coefficient A falls to the left of the material line at the design temperature square, then calculate the B value according to formula (3-3): 2
AE
where:
E——The elastic modulus of the material at the design temperature, MPa. 3.7 Welding joint coefficient
The welding joint coefficient should be determined according to the welding joint type of the pressure component and the length ratio of the non-destructive test. a) Double-sided welded butt joints and full-penetration butt joints equivalent to double-sided welding: 100% non-destructive testing = 0.95
local non-destructive testing$=0.85
160
+( 3-3)
5 Additional thickness
The additional thickness is determined according to formula (3-1):
C = Gi + Cz
Where:
C-Thickness additional amount, mm;
C, - negative deviation of titanium thickness, according to 3.5.5.1.mm; C - corrosion allowance, according to 3.5.5.2, mm. 3.5.5.1 Negative thickness deviation of titanium material
(3-1)
The negative thickness deviation of titanium plate or titanium tube shall be in accordance with the provisions of titanium material standards. When the negative deviation of the thickness of the titanium material is not greater than 0.25mm and does not exceed 6% of the nominal thickness, the negative deviation can be ignored. 3.5.5.2 Corrosion margin
In order to prevent the thickness of container components from weakening and thinning due to corrosion and mechanical wear, the corrosion margin should be considered. The specific provisions are as follows: a) For components with corrosion or wear, the corrosion margin should be based on the expected The corrosion margin is determined based on the vessel life and the corrosion rate of the medium on the metal material; 159
JB/T4745—2002
b) When the various components of the container are corroded to different degrees, different corrosion margins can be used quantity. 3.5.6 The minimum thickness of the shell after processing and forming, excluding corrosion allowance: a) cylinder 2mm;
b) other shell components according to relevant regulations.
3.5.7 Leak detection holes and leak detection structures should generally be provided between the titanium lining layer and the base layer of the pressure vessel and between the welded joint of the composite plate and the base layer. 3.6 Allowable stress
3.6.1 The allowable stress of the materials used in this standard is selected according to Chapter 4. The basis for determining the allowable stress of titanium materials is based on Table 3-1. Table 3-1 Basis for determining allowable stress
Allowable stress, MPs
(take the minimum value among the following values)
most tube
Note:| |tt||The lower limit of the standard tensile strength of titanium materials at room temperature, MPa; gi - the tensile strength of titanium materials at design temperature, MPa; product (average)
1.5||tt| |—The lower limit of the standard residual elongation stress of titanium materials at room temperature, MPa;ce2—The specified residual elongation stress of titanium materials at design temperature, MPa;s. (Average) - the average durability strength of titanium materials after 100,000 hours of fracture at the design temperature, MPa;. —The deformation limit of titanium material is 1% after 100,000 hours at the design temperature. When the MPa3.6.2 design temperature is lower than 20°C, the allowable stress at 20°C is taken. 3.6.3 Allowable axial compressive stress
The allowable axial compressive stress of a circle or a pipe shall be the smaller of the following two values: the allowable stress value of the material at the design temperature (see Chapter 4) And the B value obtained according to the following steps:
a) Calculate the coefficient A according to formula (3-2):
0.0948
A
R.
Where:
R. —Outer radius of a circle or tube, mm;. —The effective thickness of the circle or tube, mm (32)
b) According to the material, check Figure 6-3~Figure 6-8. If the A value falls to the right of the material line at the design temperature, then the This point moves up vertically and intersects the material line at the design temperature (interpolation method is used for the intermediate temperature), and then moves horizontally to the left after this intersection point to obtain the coefficient B (MPa): If the coefficient A falls to the left of the material line at the design temperature square, then calculate the B value according to formula (3-3): 2
AE
where:
E——The elastic modulus of the material at the design temperature, MPa. 3.7 Welding joint coefficient
The welding joint coefficient should be determined according to the welding joint type of the pressure component and the length ratio of the non-destructive test. a) Double-sided welded butt joints and full-penetration butt joints equivalent to double-sided welding: 100% non-destructive testing = 0.95
local non-destructive testing$=0.85
160
+( 3-3)
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