Standard No.:	JB 4732-2005
English Name:	Steel Pressure Vessels - Design by Analysis
Chinese Name:	钢制压力容器——分析设计标准
Professional Classification:	JB    Professional Standard - Machinery
Issued on:	1995-03-07
Implemented on:	1995-10-15
Status:	valid
Target Language:	English
File Format:	PDF
Word Count:	72000 words
Translation Price(USD):	1200.0
Delivery:	via email in 1 business day

Steel Pressure Vessels - Design by Analysis 1 Subject Contents and Scope 1.1 Subject content This standard is related to steel pressure vessels based on design by analysis. Design methods are provided based on elastic stress analysis, plastic failure criteria and elastic-plastic failure criteria. More strict requirements are specified for manufacture, inspection and acceptance than GB 150 "Steel Pressure Vessels". This standard shall be implemented with GB 150 simultaneously. Any one of them can be applied, if their own requirements are met. 1.2 Scope 1.2.1 This standard is applicable to: a) Vessels whose design pressures are greater than or equal to 0.1 MPa and less than 100 MPa; b) Vessels whose vacuum degrees are higher than or equal to 0.02 MPa. 1.2.2 The applicable design temperature of this standard shall be lower than the corresponding temperature by which the steel creep controlling its admissible stress intensity. 1.2.3 This standard is not applicable to the following various vessels: a) Vessels in the nuclear-energy plant; b) The compression vessel chamber as an entirety or component in the rotary or reciprocating mechanical equipments (such as pump, compressor, turbine and hydraulic cylinder); c) Frequently-transported vessels; d) Vessels whose internal diameter (as for noncircular section, width, height or diagonal) is less than 150mm; e) Directly-fired vessels. 2 Normative References GB 150 Steel pressure vessels GB/T 196 General purpose metric screw threads - Basic dimensions GB/T 197 General purpose metric metric screw threads-Tolerances GB/T 228 Metallic materials - Tensile testing at ambient temperature GB/T 229 Metallic materials - Charpy notch impact test GB/T 232 Metallic materials - Bend test GB 567 Bursting discs and bursting discs devices GB/T 699 Quality carbon structural steels GB/T 1220 Stainless steel bars GB/T 1804 General tolerances - Tolerances for linear and angular dimensions without individual tolerance indications GB/T 3077 Alloy structure steels GB/T 3280 Cold rolled stainless steel plate sheet and strip GB 3531 Low alloy steel plates for low temperature pressure vessels GB/T 4237 Hot rolled stainless steel plate sheet and strip GB 6479 Seamless steel tubes for high-pressure for chemical fertilizer equipments GB 6654 Steel plates for pressure vessels GB/T 8163 Seamless steel tubes for liquid service GB 9948 Seamless steel tubes for petroleum cracking GB 12337 Steel spherical tanks GB 13296 Seamless stainless steel tubes for boiler and heat exchanger GB/T 14976 Stainless steel seamless tubes for fluid transport GB 16749 Bellows expansion joints for pressure vessel GB 19189 Quenched and tempered high strength steel plates for pressure vessels JB 4700~4707 Pressure vessel flanges JB 4708 Welding procedure qualification for steel pressure vessels JB/T 4710 Steel vertical vessels supported by skirt JB/T 4711 Coating and packing for pressure vessels transport JB 4726 Carbon and low - alloy steel forgings for pressure vessels JB 4727 Low-alloy steel forgings for low temperature pressure vessels JB 4728 Stainless steel forgings for pressure vessels JB/T 4730.1~4730.6 Nondestructive testing of pressure equipments JB 4733 Explosive stainless clad steel plate for pressure vessels JB 4744 Mechanical property tests of product welded test coupons for steel pressure vessels 3 General Provisions 3.1 The design, manufacture, inspection and acceptance of the vessels at the scope of jurisdiction of this standard shall not only be in accordance with the requirements of this standard, but also the national decrees, legislations and regulations related to the pressure vessels. 3.2 The scope of jurisdiction of this standard means the vessel body and the connecting compression parts connected with it, which is restricted within the following scope. 3.2.1 Connection between the vessel and the outer pipeline: a) The first circumferential welding seam between the vessel nozzle and the outer pipeline; b) The first nipple of threaded connection; c) The first flange sealing surface of flange connection; d) The first sealing surface of special connecting piece or pipe fittings connecting. 3.2.2 Bearing head, flat cover and fastening pieces of the nozzle, hatch and hand-hole, etc. 3.2.3 The welding seams between the non-pressure components and the internal & external surface of the vessels. The components outside of the welding seams, such as the reinforcing ring, lug support, supporting lug and skirt, shall be in accordance with the requirements of this standard or relevant standards. 3.3 The overpressure relief devices directly connected on the vessels shall be in accordance with the requirements of Annex E. Accessories such as instruments connected on the vessels shall be in accordance with relevant standards. 3.4 Qualification and Responsibilities 3.4.1 The design and manufacturing organizations of the vessels must be possessed of sound total quality control system. The design organization shall be possessed of the corresponding design organization instrument of ratification and the manufacturing organization shall be possessed of the corresponding manufacturing license. 3.4.2 The manufacture and application of the pressure vessels must be under the supervision of the safety supervision organization of the Ministry of Labor or authorized inspection organizations. Note: the authorized inspection organizations are authorized by the pressure vessel safety supervision organization of the Ministry of Labor. 3.4.3 Responsibilities of the design organizations 3.4.3.1 The design organizations shall confirm the accuracy and integrity of the design condition analysis (trust deed). 3.4.3.2 The design organizations shall be responsible for the accuracy and integrity of the design document. 3.4.3.3 The design documents of the vessels shall at least contain stress analysis statement and design drawings. 3.4.3.4 The general vessel design drawing shall be sealed with the instrument of ratification mark of the design organizations who apply this standard. 3.4.3.5 The design data shall be kept for at least 7 years. 3.4.4 Responsibilities of the manufacturing organizations 3.4.4.1 The manufacturing organizations must manufacture in accordance with the requirements of the drawing drawings and can modify the original design only when approved by the original design organization. 3.4.4.2 The inspection departments of the manufacturing organizations shall carry out various specific inspections and tests for the vessels according to the requirements of this standard and drawings in the process of the vessel manufacture and completion, propose inspection report and be responsible for the accuracy and integrity of the reports. 3.4.4.3 The manufacturing organizations shall at least be possessed of the following technical documents for future reference for each vessel. The technical documents shall be kept for at least 7 years. a) Manufacture process drawing or process card; b) Material certificates and material lists; c) Records of the vessel welding process and heat treatment process (see Chapter 11 for their retention period); d) Records of the selective items for the manufacturer in the standard; e) Inspection records in the process of the manufacture and completion; f) Original design drawings and completion drawings of the vessels. 3.4.4.4 The manufacturing organizations shall deliver the product quality certificate to the users after confirmed by the authorized inspection organizations. 3.4.5 The legal or authorized inspection organizations shall carry out supervision and inspection for the pressure vessels in accordance with the national relevant regulations or rules and relevant requirements classified into supervision clauses in this standard. 3.5 Definition 3.5.1 Pressure: means the manometer pressure unless otherwise indicated. 3.5.2 Operating pressure: means the maximum pressure the top of the vessel may reach, under normal operating conditions. 3.5.3 Design pressure: means the setting maximum pressure of the top of the vessel; greater than or equal to the operating pressure; as the design load conditions with corresponding design temperature; as the foundation of the set pressure of the overpressure relief devices. 3.5.4 Calculated pressure: means the pressure for determining the calculated thickness of the components under corresponding design temperature (according to Table 3-1). 3.5.5 Test pressure: means the pressure on the top of the vessel in the process of the pressure test. 3.5.6 Design temperature: means the metal temperature (mean temperature along the metal section of the components) of the setting components under the normal operating conditions of the vessels. The design temperature is used as the design load condition together with the design pressure. 3.5.7 Test temperature: means the metal temperature of the vessel shell in the process of the pressure test. 3.5.8 Thickness: a) Calculated thickness: means the thickness calculated according to the formulae of each chapter; b) Design thickness: means the sum of the calculated thickness and the corrosion allowance; c) Nominal thickness: means the sum of the design thickness and the steel thickness negative deviation1) rounded up to the thickness of the standard steel specification, namely thickness indicated in the drawing; ———————— 1) When the negative thickness deviation specified by the steel standard is not greater than 0.25mm and 6% of the nominal thickness, it may be neglected. d) Effective thickness: means the nominal thickness subtracting the corrosion allowance and the negative deviation of the steel thickness. 3.6 Design requirements 3.6.1 In the design, the stress analysis and fatigue analysis shall be carried out according to the requirements of Chapter 5, Annex A, Annex B, Annex C, Annex J and Annex K. The stress intensity in the structure must not exceed the permissible limit. If the stress intensity can meet the requirements of 3.9 and 3.10, the stress analysis and fatigue analysis can be omitted. 3.6.2 As for the structure with instability as the main failure mode, not only the requirements of 3.6.1 shall be met, but also the structural stability shall be checked (see Chapter 8 for the conditions of bearing external pressure and axial compression). 3.6.3 General requirements for the design 3.6.3.1 When the design pressure is determined, the following points shall be considered: When the overpressure relief devices are loaded on the vessels, the design pressure shall be determined according to the requirements of Annex E. The vacuum vessel shall be designed with regard to bearing the external pressure. If the safety control device is installed (such as the vacuum release valve), the design pressure shall adopt the minimum value between 1.25 times of the maximum internal and external pressure difference and 0.1 MPa; if the safety control device is not installed, the design pressure shall adopt 0.1 MPa. As for the vessels with different operating conditions, they shall be designed according to the strictest operating conditions. The maximum pressure difference shall be considered for the vessels bearing the internal and external pressure or with more than two pressure chambers. 3.6.3.2 When the design temperature is determined, the following points shall be considered: The design temperature shall not be lower than the maximum temperature that the component metals may reach under the operating conditions. As for the metal temperature below 0℃, the design temperature must not be higher than the minimum temperature that the component metal may reach. In any case, the temperature of the metal surface must not exceed the allowable steel service temperature. If the metal temperature of each part of the vessels is different under operating conditions, the design temperature of each part can be determined respectively. 3.6.3.3 Load Various loads and load combination shall be considered in the design; at least the following loads shall be considered: a) Internal pressure, external pressure or the maximum pressure difference; b) Hydrostatic head; c) Deadweight of the vessel and the gravity load of the fillings under the normal working conditions or test conditions; d) Additional loads, such as the gravity loads of other auxiliary facilities, heat insulating materials, lining, pipeline, staircase and platform, etc.; e) Wind load, snow load and earthquake load; f) The counterforce of lug support, base ring, supporting lug and other bases; g) Impact load including the rapid pressure fluctuation; h) The inhomogeneous strain loads caused by various temperature conditions and the acting force caused by the expansion or shrinkage of the connecting pipes or other components. 3.6.3.4 The minimum thickness of the steel plates used for the compression parts of the vessels and their accessories shall be in accordance with the following requirements: a) The carbon steel and low alloy steel plate shall not be less than 6mm after deducting the corrosion allowance; b) The high alloy steel plate shall not be less than 3mm after deducting the corrosion allowance. 3.6.3.5 The design stress intensity of the stainless clad steel plate: a) When the design stress intensity of the clad materials is greater than or equal to 70% of that of the base materials, the clad thickness is allowed to be counted in the intensity calculation. The reduced thickness of the composite materials counted in the intensity calculation may be calculated according to formula (3-1a): (3-1a) Where: δe——Reduced thickness of the composite materials, mm; δ1——Nominal thickness of the base metal, mm; δ2——Thickness of the clad metal (corrosion allowance is omitted), mm; Sm1——Design stress intensity of the base metal, MPa; Sm2——Design stress intensity of the clad metal, MPa; b) As for the combination ratio of the clad and the base reaching the 2-level plate or the above in standard JB 4733, if the intensity of the clad materials shall be counted in the design calculation, the design stress intensity of the clad steel plate under the design temperature may be determined according to formula (3-1b): (3-1b) 3.6.3.6 Lining Corrosion resistant lining is not the lining forming into an entirety with the vessel wall, so the thickness of the lining layer shall not be counted in calculating the vessel wall thickness. 3.6.3.7 Corrosion allowance When the plate thickness of the vessel components is reduced due to corrosion, washout, mechanical wear or other environmental influence, thickness shall be increased properly except the calculated thickness determined through calculation formula or stress analysis. The thickness may be determined according to the prospective vessel life span and the corrosion rate of the media to the materials. Different corrosion allowance may be adopted for each part of the vessel with different corrosion degree. If the experience shows that corrosion does not occur in the similar application process, the corrosion allowance may not be considered. 3.6.4 Relations among the pressure, temperature and static head In the process of designing each part of the vessel, the relation among the pressure, temperature and static head must be considered according to Table 3-1. Table 3-1 Relation between the pressure and temperature State Pressure Static head1) Temperature Remark 1 The whole vessel Design pressure Omitted Concurrent design temperature Pressure and temperature indicated on the nameplate 2) If the temperature is different on each part of the vessel, the whole vessel shall adopt the maximum temperature therein Every part Pressure of each part corresponding to the design pressure Static head of each part Concurrent design temperature 2 Every part Pressure corresponding to the design temperature Static head of each part Design temperature Compared with state 1, the combination of the higher temperature and the lower pressure must be checked, or each part shall be designed according to the combination of the pressure (including the static head) and the design temperature of each part 3 The whole vessel Test pressure Omitted Test temperature Every part Test pressure Static head of each part Test temperature 4 The whole vessel Pressure corresponding to the minimum allowable temperature Omitted Minimum allowable temperature The suitability of the materials to the operating temperature shall be co-determined by the minimum allowable temperature and the material notch ductility test or the maximum stress under the low temperature Every part Pressure of each part corresponding to the minimum allowable temperature Static head of each part Minimum allowable temperature 5 Every part Operating pressure Static head of each part Metal temperature For the secondary stress and the peak stress analysis 1) Is also applicable to the pressure fluctuation caused by fluid flow. 2) If the vessel can operate under different pressure and temperature conditions, other corresponding pressure and temperature values can be indicated simultaneously. 3.6.5 Design stress intensity The design stress intensity Sm of the materials used in this standard shall adopt the values stated in Chapter 6. The basis is as follows: 3.6.5.1 Steels Except the bolt materials, the design stress intensity of general steels shall be the minimum of the following values: a) 1/2.6 of the lower limit value of the standard tensile strength under the normal temperature; b) 1/1.5 of the yield strength ReL (Rp0.2) under the normal temperature; c) 1/1.5 of the yield strength R (R ) under the design temperature. As for the components made of austenitic stainless steels, according to the application parts, 90% of the yield strength R under the design temperature may be adopted for the components for which slight permanent deformation is allowable, but the design stress intensity must not exceed 1/1.5 of the yield strength Rp0.2 under the normal temperature. This requirement is not applicable to the flange or other components for which slight deformation will cause leakage or fault. 3.6.5.2 Bolt materials The design stress intensity of the bolt materials is shown in Table 3-2. Table 3-2 Bolt design stress intensity Materials Bolt diameter, mm Heat treatment condition Design stress intensity Design temperature is lower than the creep range Carbon steel ≤M22 M24~M48 Hot rolled and normalizing R /2.7 R /2.5 Low alloy steel Martensite high alloy steel ≤M22 M24~M48 ≥M52 Slack quenching R (R ) /3.5 R (R ) /3.0 R (R ) /2.7 Austenite high alloy steel ≤M22 M24~M48 Solid solution R (R ) /1.6 R (R ) /1.5 Note: R (R ) is the yield point or 0.2% yield strength under the design temperature, MPa. 3.7 Allowable limit of the stress intensity 3.7.1 Allowable limit of the primary stress intensity The allowable limit of the primary stress intensity shall be in accordance with the following requirements, but not subject to the restriction once in accordance with 5.4.2. 3.7.1.1 When the vessel and its lug support are designed according to the combination conditions of design load and test load listed in Table 3-3, the allowable limit of the primary stress intensity shall be in accordance with the requirements of 5.3.1~5.3.3. Table 3-3 Load combination coefficient K Conditions Load combination (see 3.6.3.3) K Basic reference for the calculated stress Design load A Design pressure; vessel deadweight; gravity load of fillings, auxiliary facilities and external accessories 1.0 Under the design temperature; the thickness of the corrosion allowance is omitted B A + wind load 1), 2) 1.23) C A + earthquake load1), 2 1.23) Test load A Test pressure; vessel deadweight; gravity load of fillings, auxiliary facilities and external accessories 1.25 in hydraulic test, 1.15 in pneumatic test Under the test temperature; actual design value 1) Wind load and earthquake load are not required to be considered simultaneously. 2) The calculation methods for wind load and earthquake load shall be in accordance with the relevant requirements. 3) Primary general membrane stress shall be below the yield point. 3.7.1.2 In the test, if the pressure (including the static head) of any point of the vessel exceeds 6% of the test pressure specified in formula (3-2) and formula (3-3), the upper limit of the test pressure shall be determined according to the following requirements: In the hydraulic test: a) The primary general membrane stress intensity SⅠ calculated under the test temperature shall not exceed 90% of the material yield strength ReL (RP0.2) under the test temperature; b) The stress intensity SⅡ of the calculated primary membrane plus the primary bending stress shall not exceed the limit given by the following formulae: When SⅠ≤0.67ReL (RP0.2), SⅡ≤1.35ReL (RP0.2); When 0.67ReL (RP0.2)

Contents 1 Subject Contents and Scope 1.1 Subject content 1.2 Scope 2 Normative References 3 General Provisions 4 Terms 4.1 Stress intensity 4.2 Gross structural discontinuity 4.3 Local structural discontinuity 4.4 Normal stress 4.5 Shear stress 4.6 Membrane stress 4.7 Bending stress 4.8 Primary stress 4.9 Secondary stress Q 4.10 Peak stress F 4.11 Load stress 4.12 Thermal stress 4.13 Operating cycle 4.14 Stress cycle 4.15 Deformation 4.16 Inelasticity 4.17 Fatigue 5 General Standards of Design by Analysis 5.1 General rules 5.2 Calculation of stress intensity 5.3 Allowable limit of various stress intensity 5.4 Application of plastic analysis 5.5 Three-dimensional stress 5.6 Nozzle transition 6 Materials 6.1 General rules 6.2 Steel plate 6.3 Steel tube 6.4 Forgings 6.5 Stud and nut 7 Shell of Revolution Bearing the External Pressure 7.1 Scope 7.2 Symbol Description 7.3 Circular Cylinder 7.4 Spherical Shell 7.5 Conical Shell 7.6 Forming head 7.7 Connection between the larger end of the conical shell and the cylinder 7.8 Connection between the smaller end of the conical shell and the cylinder 7.9 Coupling of Larger and Smaller Ends 7.10 Reducer Section 8 Shell of revolution bearing the external pressure 8.1 Symbol description 8.2 Calculation of the external pressure cylinder and external pressure sphere 8.3 Design of reinforcing ring of the external pressure cylinder 8.4 Forming head 8.5 conical shell and conical head bearing external pressure 8.6 Axially-compressed cylinder 9 Flat Cover 9.1 Symbol Description 9.2 Thickness of Flat-Cover 10 Opening and Opening Reinforcement 10.1 Symbol description 10.2 Equal-area reinforcement 11 Manufacturing, Inspection and Acceptance 11.1 General Provisions 11.2 Cold and hot forming 11.3 Welding 11.4 heat treatment 11.5 Test plate and sample 11.6 Multi-layer pressure vessel 11.7 Shrunk-fit pressure vessel 11.8 Forged and welded pressure vessel 11.9 Nondestructive testing 11.10 Pressure test and gas-tightness test 11.11 Quality certificate, mark, painting, package and transportation Annex A (Normative) Stress Analysis of Basic Components and Combined Components A.1 Application Scope A.2 Deformation and Stress Analysis of the Basic Components A.3 Stress at the Joint of Various Heads and Cylindrical Shell A.4 The Stress Analysis Method of the Integrally-reinforced Shell Opening A.5 Temperature Stress Annex B (Normative) Experimental Stress Analysis B.1 General Rules B.2 Test Types B.3 Test Methods B.4 Test Results B.5 Tests to Determine Collapse Load Annex C (Normative) Design Basing on Fatigue Analysis C.1 General Provisions C.2 Procedures of Fatigue Analysis C.3 Local Structural Discontinuity C.4 Attenuation Coefficient of the Fatigue Strength of the Fillet Weld C.5 Fatigue Analysis of the Stud C.6 Thermal Stress Ratchet Action in the Shell C.7 Test Methods for Determining the Fatigue Life C.8 Stress Index Method for the Opening Fatigue Evaluation Annex D (Normative) Flanges D.1 General Provisions D.2 Symbol Explanation D.3 Flange Types D.4 Flange Connection D.5 External Pressure Flange Annex E (Normative) E.1 Application scope E.2 Definition E.3 Symbol explanation E.4 General Rules E.5 Calculation of the vessel safety release quantity E.6 Safety valve E.7 Bursting discs devices E.8 The combined device of the safety valve and the bursting discs devices E.9 Installation of the overpressure relief devices E.10 Release pipe Annex F (Normative) F.1 General Rules F.2 Steel plate Annex G (Informative) Annex H (Informative) H.1 Classification and requirements of the welded joints H.2 Other welded connection and requirements Annex I (Informative) I.1 Forms of tube plate connection structure I.2 Symbol description I.3 Stress analysis on the tube plate of the U-tube heat exchanger and other relevant components I.4 Stress analysis on the tube plate of the floating head and packing-gland heat exchanger and other relevant components I.5 Stress analysis on the tube plate of the fixed heat exchanger and other relevant components Annex J (Informative) Stress Analysis of Cylindrical Shell Opening Nozzle J.1 Application Scope J.2 Symbol Explanation J.3 Calculation Procedures J.4 Thickness Adjustment Annex K (Informative) basic requirements for finite element calculation procedures and analysis staff K.1 Calculation Procedures K.2 Analysis Staff