GB/T 150.3-2024 Pressure vessels - Part 3: Design English
1 Scope
1.1 This document specifies the general design requirements for pressure vessels and the design requirements for basic pressure components.
1.2 This document is applicable to the design calculations for internal pressure cylinders and internal pressure spheres, external pressure cylinders and external pressure spheres, heads, openings and reinforcement for openings, as well as flanges.
1.3 This document specifies the basic design requirements for non-circular cross-section vessels (see Annex A), flat steel ribbon wound cylindrical shells (see Annex B), common sealing structures (see Annex C), welded joint structures (see Annex D), jacketed vessels (see Annex G), and vessels with design temperatures below -20℃ (see Annex E), as well as the method for checking pressure vessels to prevent brittle fracture at low temperatures (see Annex F).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 150.1-2024 Pressure vessels - Part 1: General requirements
GB/T 150.2-2024 Pressure vessels - Part 2: Materials
GB/T 150.4-2024 Pressure vessels - Part 4: Fabrication, inspection and testing, and acceptance
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 713.2 Steel plate, sheet and strip for pressure equipments - Part 2: Non-alloy and alloy steel with specified temperature properties
GB/T 713.3 Steel plate, sheet and strip for pressure equipments - Part 3: Low alloy steel with specified low temperature properties
GB/T 713.4 Steel plate, sheet and strip for pressure equipments - Part 4: Nickel-alloy steels with specified low temperature properties
GB/T 713.5 Steel plate, sheet and strip for pressure equipments - Part 5: High manganese steel with specified low temperature properties
GB/T 713.6 Steel plate, sheet and strip for pressure equipments - Part 6: Quenched and tempered high strength steel
GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding
GB/T 985.2 Recommended joint preparation for submerged arc welding
GB/T 3531 Steel plates for low temperature pressure vessels
GB/T 4732 Pressure vessels design by analysis
GB/T 6479 Seamless steel tubes for high-pressure chemical fertilizer equipments
GB/T 6803 Test method for drop-weight test to determine nil-ductility transition temperature of ferritic steels
GB/T 8163 Seamless steel pipes for liquid service
GB/T 9948 Seamless steel tubes for petroleum cracking
GB/T 19189 Quenched and tempered high strength steel plates for pressure vessels
GB/T 21143-2014 Metallic materials - Unified method of test for determination of quasistatic fracture toughness
GB/T 25774.1 Test methods for welding consumables - Part 1: Preparation of deposited metal test pieces and specimens for mechanical properties in steel, nickel and nickel alloys
GB/T 26929 Terminology for pressure vessels
HG/T 20592 Steel pipe flanges (PN designated)
HG/T 20615 Steel pipe flanges (Class designated)
HG/T 20623 Large diameter steel pipe flanges (Class designated)
NB/T 11025 Reinforcing pad
NB/T 47008 Carbon and alloy steel forgings for pressure equipment
NB/T 47009 Alloy steel forgings for low temperature pressure equipment
NB/T 47013.2 Nondestructive testing of pressure equipments - Part 2: Radiographic testing
NB/T 47013.3 Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing
NB/T 47013.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
NB/T 47013.5 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
NB/T 47014 Welding procedure qualification for pressure equipments
NB/T 47016 Mechanical property tests of product welded test coupons for pressure equipments
NB/T 47018 (All parts) Technical permission of welding materials for pressure equipment
NB/T 47019.4 Purchase technical specification for boiler & heat exchanger tubes - Part 4: Low alloy steel for low-temperature service
NB/T 47020 Type and specification for pressure vessel flanges
NB/T 47021 A-type socket-weld flange
NB/T 47022 B-type socket-weld flange
NB/T 47023 Welding neck flange
ISO 10423 Petroleum and natural gas industries - Drilling and production equipment - Wellhead and tree equipment
TSG 21 Supervision regulation on safety technology for stationary pressure vessel
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 150.1-2024, GB/T 26929 and GB/T 4732 apply.
4 General
4.1 General requirements
4.1.1 Accept the design conditions proposed by the user or the design entrusting party and verify their completeness, standardization, and feasibility.
4.1.2 Determine the main failure modes and corresponding failure criteria, and conduct risk assessments if necessary.
4.1.3 Determine the main standards, specifications, and calculation methods on which the design is based.
4.1.4 Determine or confirm the properties of the contents (explosion risk, toxicity hazard, corrosivity, etc.), contents grouping, corrosion type and corrosion allowance, and design service life.
4.1.5 Determine or confirm the design working conditions and design conditions.
4.1.6 Determine the material of each component according to GB/T 150.2-2024, specifying the grade, allowable stress, mechanical properties, and supply condition of materials. When necessary, propose the re-inspection requirements for component materials and the low and high temperature performance indicators. If the design temperature of the pressure vessel is lower than the lower limit of the material's service temperature specified in GB/T 150.2-2024, perform the checking to prevent brittle fracture at low temperature according to Annex F.
4.1.7 Determine or confirm the connection form of the pressure components, support form of the vessel, etc.
4.1.8 Determine the loads to be considered, principles for load combination, etc.
4.1.9 Propose corresponding fabrication technical requirements, including requirements for processing and forming, welding, assembly, nondestructive testing, heat treatment, pressure test, leakage test, etc.
4.2 Additional requirements
This document specifies the basic design requirements for non-circular cross-section vessels, flat steel ribbon wound cylindrical shells, common sealing structures, welded joint structures, jacketed vessels, vessels with design temperatures below -20℃ and the method for checking pressure vessels to prevent brittle fracture at low temperatures, among which:
a) Additional requirements for the design, fabrication and acceptance of non-circular cross-section vessels are as specified in Annex A;
b) Additional requirements for the design of flat steel ribbon wound cylindrical shells are as specified in Annex B;
c) Additional requirements for the design of common sealing structures are as specified in Annex C;
d) Additional requirements for the design and fabrication of welded joint structures are as specified in Annex D;
e) Additional requirements for the materials and design of vessels with design temperatures below -20℃ are as specified in Annex E;
f) Additional requirements for the method used to check pressure vessels to prevent brittle fracture at low temperatures are as specified in Annex F;
g) The basic design requirements for jacketed vessels are as specified in Annex G.
5 Internal pressure cylinders and internal pressure spheres
5.1 General requirements
Single-layer, wrapped and shrink fit cylinders and spheres subjected to internal pressure shall be calculated using the equations given in this clause. Design calculations for flat steel ribbon wound cylindrical shells shall be carried out according to those specified in Annex B.
5.2 Terms, definitions and symbols
5.2.1 Terms and definitions
For the purposes of this clause, the terms and definitions given in GB/T 150.1-2024 apply.
5.2.2 Symbols
For the purposes of this clause, the following symbols apply:
Di——the inner diameter of cylinder or sphere, mm;
Do——the outer diameter of cylinder or sphere (Do=Di+2δn), mm;
K——the diameter ratio, ;
pc——the calculation pressure, MPa;
[pw]——the maximum allowable working pressure of cylinder or sphere, MPa;
δ——the required thickness of cylinder or sphere, mm;
δe——the effective thickness of cylinder or sphere, mm;
δi——the nominal thickness of inner cylinder of wrapped cylinder or shrink fit cylinder, mm;
δn——the nominal thickness of cylinder or sphere, mm;
δo——the total thickness of the laminate layers of a wrapped cylinder or of the shrink fit layers of a shrink fit cylinder, mm;
σt——the calculated stress of cylinder or sphere at the design temperature, MPa;
——the circumferential stress of cylinder at the design temperature, MPa;
[σ]t——the allowable stress of cylinder or sphere material at the design temperature (according to those specified in GB/T 150.2-2024), MPa;
[σi]t——the allowable stress of the inner cylinder material of wrapped cylinder or shrink fit cylinder at the design temperature (according to those specified in GB/T 150.2-2024), MPa;
[σo]t——the allowable stress of the laminate layer material of a wrapped cylinder or of the shrink fit layer material of a shrink fit cylinder at the design temperature, MPa;
φ——the welded joint coefficient;
φi——the welded joint coefficient for the inner cylinder of wrapped cylinder or shrink fit cylinder;
φo——the welded joint coefficient for the laminate layers of a wrapped cylinder or of the shrink fit layers of a shrink fit cylinder.
5.3 Cylinder-related calculations
The applicable range for Equations (5-1) to (5-8) is K≤1.5 or pc≤0.4[σ]tφ.
a) The required thickness of cylinder at the design temperature shall be calculated using either Equation (5-1) or Equation (5-2):
(5-1)
(5-2)
b) The circumferential stress of cylinder shall be calculated using either Equation (5-3) or Equation (5-4):
(5-3)
(5-4)
The calculated stress σt shall satisfy Equation (5-5):
(5-5)
The [σ]tφ of wrapped cylinders and shrink fit cylinders shall be calculated using Equation (5-6):
(5-6)
where, φi=1.0 and φo=0.95.
c) The maximum allowable working pressure of cylinder at the design temperature shall be calculated using either Equation (5-7) or Equation (5-8):
(5-7)
(5-8)
5.4 Sphere-related calculations
The applicable range for Equations (5-9) to (5-15) is K≤1.35 or Pc≤0.6[σ]tφ.
a) The required thickness of sphere at the design temperature shall be calculated using either Equation (5-9) or Equation (5-10):
(5-9)
(5-10)
b) The calculated stress of sphere shall be calculated using either Equation (5-11) or Equation (5-12):
(5-11)
(5-12)
σt shall satisfy Equation (5-13):
σt≤[σ]tφ (5-13)
c) The maximum allowable working pressure of sphere at the design temperature shall be calculated using either Equation (5-14) or Equation (5-15):
(5-14)
(5-15)
6 External pressure cylinder and external pressure sphere
6.1 General requirements
The requirements outlined in this clause apply to the design of external pressure cylinders (including pipes/tubes) and external pressure spheres.
6.2 Terms, definitions and symbols
6.2.1 Terms and definitions
For the purposes of this clause, the terms and definitions given in GB/T 150.1-2024 apply.
6.2.2 Symbols
For the purposes of this clause, the following symbols apply:
A——the external pressure strain coefficient;
As——the cross sectional area of reinforcing ring, mm2;
B——the external pressure stress coefficient, MPa;
Di——the inner diameter of cylinder, mm;
Do——the outer diameter of cylinder (Do=Di+2δn), mm;
Et——the elasticity modulus of the material at the design temperature, MPa;
hi——the curved surface depth of the head, mm;
hs1, hs2——the parameters of reinforcing ring, see Figure 6-18, mm;
I——the inertia moment required for the combined section of reinforcing ring and cylinder, mm4;
Is——the inertia moment of the combined cross section of the reinforcing ring and the effective section of the cylinder acting as a reinforcement relative to centroidal axis passing through the cross section parallel to the axis of the cylinder, mm4;
L——the calculated length of cylinder, mm;
LS——the half the sum of the distances from the centerline of the reinforcing ring to the centerlines of the adjacent reinforcing rings. If adjacent to a convex head, 1/3 the curved surface depth of the head shall also be included in the length, mm;
pc——the calculated external pressure, MPa;
[p]——the allowable external pressure, MPa;
ReL(Rp0.2)——the yield strength (or 0.2% non-proportional extension strength) of cylinder or pipe/tube material at standard room temperature, MPa;
——the yield strength (or 0.2% non-proportional extension strength) of cylinder or pipe/tube material at the design temperature, MPa;
Ro——the outer radius of sphere, mm;
t——the clearance between intermittent welds, mm;
δe——the effective thickness of cylinder or sphere, mm;
δn——the nominal thickness of cylinder or sphere, mm;
δs1, δs2——the parameters of reinforcing ring, see Figure 6-18, mm;
σo——the stress, MPa;
[σ]t——the allowable stress of cylinder or pipe/tube material at the design temperature (according to those specified in GB/T 150.2-2024), MPa.
6.3 Check for stability of external pressure cylinders
6.3.1 Determination of calculated length
The calculated length of the cylinder shall be the distance between two adjacent support lines on the cylinder, as shown in Figure 6-1, and shall meet the following requirements.
a) As shown in Figures 6-1 a-1) and a-2), the calculated length is the total length of the cylinder plus 1/3 of the curved surface depth of each convex head. When Figure 6-1 a-2) applies, the design calculation shall be performed using the indicated length L, the outer diameters of the cylinders at the connection, and their corresponding thicknesses. The required thickness of the unflanged or flanged conical shell and the transition section shall not be less than that of the connected cylinder. In addition, when there is no flanging between the conical shell and the cylinder, the area check requirement shall also be met (see 7.6.6.4.1 or 7.6.6.5.1).
b) As shown in Figure 6-1 b-1), the calculated length is the total length of the equipment. In this case, the design calculation shall be performed using the indicated length L, the outer diameters of the cylinders at the connection, and their corresponding thicknesses. The required thickness of the unflanged or flanged conical shell and the transition section shall not be less than that of the connected cylinder. In addition, when there is no flanging between the conical shell and the cylinder, the area check requirement shall also be met (see 7.6.6.4.1 or 7.6.6.5.1).
As shown in Figure 6-1 b-2), when the connection between the cylinder and the conical shell may be considered as a support line, the calculated length of the cylinder section is the total length of the cylinder. The connection between the cylinder and the conical shell shall meet the requirements of 7.6.6.4 or 7.6.6.5. When the inertia moment of the cylinder-conical shell combined cross-section as a support line is insufficient, the use of a cylinder-conical shell-reinforcing ring combined structure is allowed to increase the inertia moment of the combined cross-section, so that it meets the requirements of 7.6.6.4.2 or 7.6.6.5.2.
c) As shown in Figures 6-1 c-1) and c-2), when the cylinder section has reinforcing rings (or components that can serve as reinforcement), the calculated length is the distance between the centerlines of adjacent reinforcing rings.
When Figure 6-1 c-2) applies, the design calculation shall be performed using the indicated length L, the outer diameters of the cylinders at the connection, and their corresponding thicknesses. The required thickness of the unflanged or flanged conical shell and the transition section shall not be less than that of the connected cylinder. In addition, when there is no flanging between the conical shell and the cylinder, the area check requirement shall also be met (see 7.6.6.4.1 or 7.6.6.5.1).
d) As shown in Figure 6-1 d), the calculated length is the distance between the centerline of the first reinforcing ring of the cylinder and the tangent line of the convex head plus 1/3 of the curved surface depth of the convex head.
e) As shown in Figures 6-1 e-1), e-2), and f), when the connection between the cylinder and the conical shell may be considered as a support line, the calculated length is the distance between this connection and the adjacent support line. The connection between the cylinder and the conical shell shall meet the requirements of 7.6.6.4 or 7.6.6.5. When the inertia moment of the cylinder-conical shell combined cross-section as a support line is insufficient, the use of a cylinder-conical shell-reinforcing ring combined structure is allowed to increase the inertia moment of the combined cross-section, so that it meets the requirements of 7.6.6.4.2 or 7.6.6.5.2.
In Figure 6-1 f), LX refers to the axial length of the conical shell section, and its external pressure calculated length is the equivalent length Le, as specified in 7.6.6.
f) For a jacketed cylinder as shown in Figure 6-1 g), the calculated length is the length of the cylinder subjected to external pressure; if it has a convex head, the calculated length shall also be added with 1/3 of the curved surface depth of the head; if there are reinforcing rings (or components that can serve as reinforcement), the calculation shall be performed according to Figures 6-1 c-1), c-2), and d).
Note: A support line means a cross section in this place that has sufficient inertia moment to ensure that no instability occurs under external pressure.
Note: The connection between the cylinder and the conical shell is considered as a support line.
Figure 6-1 Calculated length of external pressure cylinder
Foreword I Introduction V 1 Scope 2 Normative references 3 Terms and definitions 4 General 5 Cylinders and spheres under internal pressure 6 Cylinders and spheres under external pressure 7 Heads 8 Opening and reinforcement for opening 9 Flanges Annex A (Normative) Non-circular cross-section vessels Annex B (Normative) Flat steel ribbon wound cylindrical shells Annex C (Normative) Sealing structure Annex D (Normative) Welded joint structures Annex E (Normative) Vessels with design temperatures below -20℃ Annex F (Normative) Methods for checking pressure vessels to prevent brittle fracture at low temperatures Annex G (Nominative) Basic requirements for jacketed vessels
GB/T 150.3-2024 Pressure vessels - Part 3: Design English
1 Scope
1.1 This document specifies the general design requirements for pressure vessels and the design requirements for basic pressure components.
1.2 This document is applicable to the design calculations for internal pressure cylinders and internal pressure spheres, external pressure cylinders and external pressure spheres, heads, openings and reinforcement for openings, as well as flanges.
1.3 This document specifies the basic design requirements for non-circular cross-section vessels (see Annex A), flat steel ribbon wound cylindrical shells (see Annex B), common sealing structures (see Annex C), welded joint structures (see Annex D), jacketed vessels (see Annex G), and vessels with design temperatures below -20℃ (see Annex E), as well as the method for checking pressure vessels to prevent brittle fracture at low temperatures (see Annex F).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 150.1-2024 Pressure vessels - Part 1: General requirements
GB/T 150.2-2024 Pressure vessels - Part 2: Materials
GB/T 150.4-2024 Pressure vessels - Part 4: Fabrication, inspection and testing, and acceptance
GB/T 228 (All parts) Metallic materials - Tensile testing
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 713.2 Steel plate, sheet and strip for pressure equipments - Part 2: Non-alloy and alloy steel with specified temperature properties
GB/T 713.3 Steel plate, sheet and strip for pressure equipments - Part 3: Low alloy steel with specified low temperature properties
GB/T 713.4 Steel plate, sheet and strip for pressure equipments - Part 4: Nickel-alloy steels with specified low temperature properties
GB/T 713.5 Steel plate, sheet and strip for pressure equipments - Part 5: High manganese steel with specified low temperature properties
GB/T 713.6 Steel plate, sheet and strip for pressure equipments - Part 6: Quenched and tempered high strength steel
GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding
GB/T 985.2 Recommended joint preparation for submerged arc welding
GB/T 3531 Steel plates for low temperature pressure vessels
GB/T 4732 Pressure vessels design by analysis
GB/T 6479 Seamless steel tubes for high-pressure chemical fertilizer equipments
GB/T 6803 Test method for drop-weight test to determine nil-ductility transition temperature of ferritic steels
GB/T 8163 Seamless steel pipes for liquid service
GB/T 9948 Seamless steel tubes for petroleum cracking
GB/T 19189 Quenched and tempered high strength steel plates for pressure vessels
GB/T 21143-2014 Metallic materials - Unified method of test for determination of quasistatic fracture toughness
GB/T 25774.1 Test methods for welding consumables - Part 1: Preparation of deposited metal test pieces and specimens for mechanical properties in steel, nickel and nickel alloys
GB/T 26929 Terminology for pressure vessels
HG/T 20592 Steel pipe flanges (PN designated)
HG/T 20615 Steel pipe flanges (Class designated)
HG/T 20623 Large diameter steel pipe flanges (Class designated)
NB/T 11025 Reinforcing pad
NB/T 47008 Carbon and alloy steel forgings for pressure equipment
NB/T 47009 Alloy steel forgings for low temperature pressure equipment
NB/T 47013.2 Nondestructive testing of pressure equipments - Part 2: Radiographic testing
NB/T 47013.3 Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing
NB/T 47013.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
NB/T 47013.5 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
NB/T 47014 Welding procedure qualification for pressure equipments
NB/T 47016 Mechanical property tests of product welded test coupons for pressure equipments
NB/T 47018 (All parts) Technical permission of welding materials for pressure equipment
NB/T 47019.4 Purchase technical specification for boiler & heat exchanger tubes - Part 4: Low alloy steel for low-temperature service
NB/T 47020 Type and specification for pressure vessel flanges
NB/T 47021 A-type socket-weld flange
NB/T 47022 B-type socket-weld flange
NB/T 47023 Welding neck flange
ISO 10423 Petroleum and natural gas industries - Drilling and production equipment - Wellhead and tree equipment
TSG 21 Supervision regulation on safety technology for stationary pressure vessel
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 150.1-2024, GB/T 26929 and GB/T 4732 apply.
4 General
4.1 General requirements
4.1.1 Accept the design conditions proposed by the user or the design entrusting party and verify their completeness, standardization, and feasibility.
4.1.2 Determine the main failure modes and corresponding failure criteria, and conduct risk assessments if necessary.
4.1.3 Determine the main standards, specifications, and calculation methods on which the design is based.
4.1.4 Determine or confirm the properties of the contents (explosion risk, toxicity hazard, corrosivity, etc.), contents grouping, corrosion type and corrosion allowance, and design service life.
4.1.5 Determine or confirm the design working conditions and design conditions.
4.1.6 Determine the material of each component according to GB/T 150.2-2024, specifying the grade, allowable stress, mechanical properties, and supply condition of materials. When necessary, propose the re-inspection requirements for component materials and the low and high temperature performance indicators. If the design temperature of the pressure vessel is lower than the lower limit of the material's service temperature specified in GB/T 150.2-2024, perform the checking to prevent brittle fracture at low temperature according to Annex F.
4.1.7 Determine or confirm the connection form of the pressure components, support form of the vessel, etc.
4.1.8 Determine the loads to be considered, principles for load combination, etc.
4.1.9 Propose corresponding fabrication technical requirements, including requirements for processing and forming, welding, assembly, nondestructive testing, heat treatment, pressure test, leakage test, etc.
4.2 Additional requirements
This document specifies the basic design requirements for non-circular cross-section vessels, flat steel ribbon wound cylindrical shells, common sealing structures, welded joint structures, jacketed vessels, vessels with design temperatures below -20℃ and the method for checking pressure vessels to prevent brittle fracture at low temperatures, among which:
a) Additional requirements for the design, fabrication and acceptance of non-circular cross-section vessels are as specified in Annex A;
b) Additional requirements for the design of flat steel ribbon wound cylindrical shells are as specified in Annex B;
c) Additional requirements for the design of common sealing structures are as specified in Annex C;
d) Additional requirements for the design and fabrication of welded joint structures are as specified in Annex D;
e) Additional requirements for the materials and design of vessels with design temperatures below -20℃ are as specified in Annex E;
f) Additional requirements for the method used to check pressure vessels to prevent brittle fracture at low temperatures are as specified in Annex F;
g) The basic design requirements for jacketed vessels are as specified in Annex G.
5 Internal pressure cylinders and internal pressure spheres
5.1 General requirements
Single-layer, wrapped and shrink fit cylinders and spheres subjected to internal pressure shall be calculated using the equations given in this clause. Design calculations for flat steel ribbon wound cylindrical shells shall be carried out according to those specified in Annex B.
5.2 Terms, definitions and symbols
5.2.1 Terms and definitions
For the purposes of this clause, the terms and definitions given in GB/T 150.1-2024 apply.
5.2.2 Symbols
For the purposes of this clause, the following symbols apply:
Di——the inner diameter of cylinder or sphere, mm;
Do——the outer diameter of cylinder or sphere (Do=Di+2δn), mm;
K——the diameter ratio, ;
pc——the calculation pressure, MPa;
[pw]——the maximum allowable working pressure of cylinder or sphere, MPa;
δ——the required thickness of cylinder or sphere, mm;
δe——the effective thickness of cylinder or sphere, mm;
δi——the nominal thickness of inner cylinder of wrapped cylinder or shrink fit cylinder, mm;
δn——the nominal thickness of cylinder or sphere, mm;
δo——the total thickness of the laminate layers of a wrapped cylinder or of the shrink fit layers of a shrink fit cylinder, mm;
σt——the calculated stress of cylinder or sphere at the design temperature, MPa;
——the circumferential stress of cylinder at the design temperature, MPa;
[σ]t——the allowable stress of cylinder or sphere material at the design temperature (according to those specified in GB/T 150.2-2024), MPa;
[σi]t——the allowable stress of the inner cylinder material of wrapped cylinder or shrink fit cylinder at the design temperature (according to those specified in GB/T 150.2-2024), MPa;
[σo]t——the allowable stress of the laminate layer material of a wrapped cylinder or of the shrink fit layer material of a shrink fit cylinder at the design temperature, MPa;
φ——the welded joint coefficient;
φi——the welded joint coefficient for the inner cylinder of wrapped cylinder or shrink fit cylinder;
φo——the welded joint coefficient for the laminate layers of a wrapped cylinder or of the shrink fit layers of a shrink fit cylinder.
5.3 Cylinder-related calculations
The applicable range for Equations (5-1) to (5-8) is K≤1.5 or pc≤0.4[σ]tφ.
a) The required thickness of cylinder at the design temperature shall be calculated using either Equation (5-1) or Equation (5-2):
(5-1)
(5-2)
b) The circumferential stress of cylinder shall be calculated using either Equation (5-3) or Equation (5-4):
(5-3)
(5-4)
The calculated stress σt shall satisfy Equation (5-5):
(5-5)
The [σ]tφ of wrapped cylinders and shrink fit cylinders shall be calculated using Equation (5-6):
(5-6)
where, φi=1.0 and φo=0.95.
c) The maximum allowable working pressure of cylinder at the design temperature shall be calculated using either Equation (5-7) or Equation (5-8):
(5-7)
(5-8)
5.4 Sphere-related calculations
The applicable range for Equations (5-9) to (5-15) is K≤1.35 or Pc≤0.6[σ]tφ.
a) The required thickness of sphere at the design temperature shall be calculated using either Equation (5-9) or Equation (5-10):
(5-9)
(5-10)
b) The calculated stress of sphere shall be calculated using either Equation (5-11) or Equation (5-12):
(5-11)
(5-12)
σt shall satisfy Equation (5-13):
σt≤[σ]tφ (5-13)
c) The maximum allowable working pressure of sphere at the design temperature shall be calculated using either Equation (5-14) or Equation (5-15):
(5-14)
(5-15)
6 External pressure cylinder and external pressure sphere
6.1 General requirements
The requirements outlined in this clause apply to the design of external pressure cylinders (including pipes/tubes) and external pressure spheres.
6.2 Terms, definitions and symbols
6.2.1 Terms and definitions
For the purposes of this clause, the terms and definitions given in GB/T 150.1-2024 apply.
6.2.2 Symbols
For the purposes of this clause, the following symbols apply:
A——the external pressure strain coefficient;
As——the cross sectional area of reinforcing ring, mm2;
B——the external pressure stress coefficient, MPa;
Di——the inner diameter of cylinder, mm;
Do——the outer diameter of cylinder (Do=Di+2δn), mm;
Et——the elasticity modulus of the material at the design temperature, MPa;
hi——the curved surface depth of the head, mm;
hs1, hs2——the parameters of reinforcing ring, see Figure 6-18, mm;
I——the inertia moment required for the combined section of reinforcing ring and cylinder, mm4;
Is——the inertia moment of the combined cross section of the reinforcing ring and the effective section of the cylinder acting as a reinforcement relative to centroidal axis passing through the cross section parallel to the axis of the cylinder, mm4;
L——the calculated length of cylinder, mm;
LS——the half the sum of the distances from the centerline of the reinforcing ring to the centerlines of the adjacent reinforcing rings. If adjacent to a convex head, 1/3 the curved surface depth of the head shall also be included in the length, mm;
pc——the calculated external pressure, MPa;
[p]——the allowable external pressure, MPa;
ReL(Rp0.2)——the yield strength (or 0.2% non-proportional extension strength) of cylinder or pipe/tube material at standard room temperature, MPa;
——the yield strength (or 0.2% non-proportional extension strength) of cylinder or pipe/tube material at the design temperature, MPa;
Ro——the outer radius of sphere, mm;
t——the clearance between intermittent welds, mm;
δe——the effective thickness of cylinder or sphere, mm;
δn——the nominal thickness of cylinder or sphere, mm;
δs1, δs2——the parameters of reinforcing ring, see Figure 6-18, mm;
σo——the stress, MPa;
[σ]t——the allowable stress of cylinder or pipe/tube material at the design temperature (according to those specified in GB/T 150.2-2024), MPa.
6.3 Check for stability of external pressure cylinders
6.3.1 Determination of calculated length
The calculated length of the cylinder shall be the distance between two adjacent support lines on the cylinder, as shown in Figure 6-1, and shall meet the following requirements.
a) As shown in Figures 6-1 a-1) and a-2), the calculated length is the total length of the cylinder plus 1/3 of the curved surface depth of each convex head. When Figure 6-1 a-2) applies, the design calculation shall be performed using the indicated length L, the outer diameters of the cylinders at the connection, and their corresponding thicknesses. The required thickness of the unflanged or flanged conical shell and the transition section shall not be less than that of the connected cylinder. In addition, when there is no flanging between the conical shell and the cylinder, the area check requirement shall also be met (see 7.6.6.4.1 or 7.6.6.5.1).
b) As shown in Figure 6-1 b-1), the calculated length is the total length of the equipment. In this case, the design calculation shall be performed using the indicated length L, the outer diameters of the cylinders at the connection, and their corresponding thicknesses. The required thickness of the unflanged or flanged conical shell and the transition section shall not be less than that of the connected cylinder. In addition, when there is no flanging between the conical shell and the cylinder, the area check requirement shall also be met (see 7.6.6.4.1 or 7.6.6.5.1).
As shown in Figure 6-1 b-2), when the connection between the cylinder and the conical shell may be considered as a support line, the calculated length of the cylinder section is the total length of the cylinder. The connection between the cylinder and the conical shell shall meet the requirements of 7.6.6.4 or 7.6.6.5. When the inertia moment of the cylinder-conical shell combined cross-section as a support line is insufficient, the use of a cylinder-conical shell-reinforcing ring combined structure is allowed to increase the inertia moment of the combined cross-section, so that it meets the requirements of 7.6.6.4.2 or 7.6.6.5.2.
c) As shown in Figures 6-1 c-1) and c-2), when the cylinder section has reinforcing rings (or components that can serve as reinforcement), the calculated length is the distance between the centerlines of adjacent reinforcing rings.
When Figure 6-1 c-2) applies, the design calculation shall be performed using the indicated length L, the outer diameters of the cylinders at the connection, and their corresponding thicknesses. The required thickness of the unflanged or flanged conical shell and the transition section shall not be less than that of the connected cylinder. In addition, when there is no flanging between the conical shell and the cylinder, the area check requirement shall also be met (see 7.6.6.4.1 or 7.6.6.5.1).
d) As shown in Figure 6-1 d), the calculated length is the distance between the centerline of the first reinforcing ring of the cylinder and the tangent line of the convex head plus 1/3 of the curved surface depth of the convex head.
e) As shown in Figures 6-1 e-1), e-2), and f), when the connection between the cylinder and the conical shell may be considered as a support line, the calculated length is the distance between this connection and the adjacent support line. The connection between the cylinder and the conical shell shall meet the requirements of 7.6.6.4 or 7.6.6.5. When the inertia moment of the cylinder-conical shell combined cross-section as a support line is insufficient, the use of a cylinder-conical shell-reinforcing ring combined structure is allowed to increase the inertia moment of the combined cross-section, so that it meets the requirements of 7.6.6.4.2 or 7.6.6.5.2.
In Figure 6-1 f), LX refers to the axial length of the conical shell section, and its external pressure calculated length is the equivalent length Le, as specified in 7.6.6.
f) For a jacketed cylinder as shown in Figure 6-1 g), the calculated length is the length of the cylinder subjected to external pressure; if it has a convex head, the calculated length shall also be added with 1/3 of the curved surface depth of the head; if there are reinforcing rings (or components that can serve as reinforcement), the calculation shall be performed according to Figures 6-1 c-1), c-2), and d).
Note: A support line means a cross section in this place that has sufficient inertia moment to ensure that no instability occurs under external pressure.
a-1) External pressure cylinder structure 1 a-2) External pressure cylinder structure 2
b-1) External pressure cylinder structure 3 b-2) External pressure cylinder structure 4
c-1) External pressure cylinder structure 5 c-2) External pressure cylinder structure 6 d) External pressure cylinder structure 7
e-1) External pressure cylinder structure 8 e-2) External pressure cylinder structure 9 f) External pressure cylinder structure 10
g) External pressure cylinder structure 11
Note: The connection between the cylinder and the conical shell is considered as a support line.
Figure 6-1 Calculated length of external pressure cylinder
Contents of GB/T 150.3-2024
Foreword I
Introduction V
1 Scope
2 Normative references
3 Terms and definitions
4 General
5 Cylinders and spheres under internal pressure
6 Cylinders and spheres under external pressure
7 Heads
8 Opening and reinforcement for opening
9 Flanges
Annex A (Normative) Non-circular cross-section vessels
Annex B (Normative) Flat steel ribbon wound cylindrical shells
Annex C (Normative) Sealing structure
Annex D (Normative) Welded joint structures
Annex E (Normative) Vessels with design temperatures below -20℃
Annex F (Normative) Methods for checking pressure vessels to prevent brittle fracture at low temperatures
Annex G (Nominative) Basic requirements for jacketed vessels
