HG 20581-1998 Regulations on the selection of materials for steel chemical containers
Some standard content:
Industry Standard of the People's Republic of China
HG20581-1998
Specification for Materials Selected of Steel Chemical Vessels1998-11-18 Issued
State Administration of Petroleum and Chemical Industry
199903-01 Implementation
Industry Standard of the People's Republic of China
Specification for Materials Selected of Steel Chemical Vessels VesselsHG20581-1998
Editor: National Chemical Equipment Design Technology Center Station Approval Department: State Petroleum and Chemical Industry Bureau Implementation Date: March 1, 1999 National Chemical Engineering Construction Standard Editing Center (formerly the Engineering Construction Standard Editing Center of the Ministry of Chemical Industry) 1999 Beijing
This standard (HG20581-1998) is based on the original standard (HGJ15-89), based on the experience gained from many years of implementation, and based on the content of national standard GB150-1998 and the standard specifications of domestic and foreign engineering companies in recent years. The newly revised standard has the following major changes compared with the original standard: 1. Add the use of austenitic stainless steel welded steel pipes; 2. Modify the use of carbon structural steel;
3. Modify the use of materials in wet H, S stress brain corrosion environment; 4. Modify the use of materials in liquid ammonia stress corrosion environment; 5. Change the use of steel to "use of steel produced according to foreign standards"; 6. Cancel the provisions on the use of steel upgrades in the original standard. Appendix A and B of this standard are the appendices of this standard. Appendix C, D and E of this standard are suggestive appendices. This standard is proposed and managed by the National Chemical Equipment Design Technology Center. This standard is edited by the National Chemical Equipment Design Technology Center. The main drafters of this standard: Ying Daoyan Hong Dexiao 28
HG20581 "Provisions for the Selection of Materials for Steel Chemical Containers" is a supplement and specification of GB150 "Steel Pressure Vessels" in combination with the specific conditions of chemical container design. It stipulates the selection, technical requirements, use restrictions and scope of steel and welding materials for steel chemical containers, the use of new materials and steel produced according to foreign standards, and steel substitution. Unless otherwise specified, the scope of use, reference standards and definitions of this standard are the same as those of GB150 "Steel Pressure Vessels".
This standard is applicable to the design of welded chemical container materials of carbon steel, low alloy high strength steel, pearlite heat resistant steel, stainless steel and stainless composite steel plate with a design pressure not exceeding 35.0MPa and a design temperature above -20C. The types of materials include rolled products, forgings, castings and welding materials.
The selection, technical requirements and scope of use of the container body (shell, head, pipe, flange, tube sheet, etc.) and its accessories, welding materials shall comply with the requirements of this standard. When the design has higher or special requirements for materials, it should be indicated on the drawings or corresponding documents. 29
Carbon steel: an iron-carbon alloy with a manganese content of less than or equal to 1.20%, a carbon content of less than or equal to 2.0%, and no intentional addition of other alloying elements (Si, AI and other elements may be added for deoxidation purposes). Low carbon steel generally refers to carbon steel with a carbon content of less than or equal to 0.25%. Low alloy high strength steel: an alloy steel with a total alloy content of less than 3% for the main purpose of improving the strength of steel and improving comprehensive performance. Low carbon, weldable low alloy structural steels such as 16MnR and 18MnMoNbR are often used in chemical containers. Pearlite heat-resistant steel is a low-carbon pearlite heat-resistant steel with the main purpose of improving the heat resistance and hydrogen resistance of steel, and adding alloying elements such as chromium (≤10%) and molybdenum, such as 0.5Mo, 1V4Cr-0.5Mo.5Cr-0.5Mo, etc. Low alloy steel is a general term for low alloy high strength steel and pearlite heat-resistant steel. Stainless steel is an alloy steel with a nominal chromium content greater than or equal to 13% that is stainless in the atmosphere. According to the metallographic structure of steel at room temperature, it can be divided into ferritic stainless steel, austenitic stainless steel, duplex stainless steel, martensitic stainless steel, etc. Austenitic stainless steel is often used in chemical containers. However, ferritic stainless steel, duplex stainless steel, etc. are also used from time to time. Austenitic stainless steel is a stainless steel with a metallographic structure of mostly austenite at room temperature, such as 0Cr18Ni9, 0Cr18Ni12Mo2Ti, etc. Ferritic stainless steel is a stainless steel with a metallographic structure of ferrite at room temperature, such as 0Cr13AI, etc. Ferritic steel is a general term for carbon steel, low alloy high strength steel, pearlite heat resistant steel and ferritic stainless steel. Pressure vessels and pressure components are a general term for low pressure, medium pressure and high pressure vessels and their pressure components. The main pressure components refer to the shell and formed heads of pressure vessels, which are mainly subjected to the overall primary membrane stress. Non-pressure components are a general term for non-pressure components in normal pressure vessels and pressure vessels. 30
3 General provisions
The quality and specifications of steel (steel plates, steel pipes, profiles, forgings) shall comply with the following current national standards, industry standards or relevant technical conditions. 3.0.1
GB1591
GB3077
GB1220
GB1221
GB6653
GB6654
GB5681
GB3274
GB4237
GB4238
GB8165
GB8163
GB13296
《Carbon Structural Steel》
《Technical Conditions for High-quality Carbon Structural Steel》
《Low-alloy Structural Steel》
《Alloy Steel》 "Technical Conditions for Metal Structural Steel"
"Stainless Steel Bars"
"Heat-resistant Steel Bars"
"Steel Plates for Welded Gas Cylinders"
"Carbon Steel and Low-alloy Steel Thick Plates for Pressure Vessels"
"Hot-rolled Steel Strips for Pressure Vessels"
"Carbon Steel and Low-alloy Steel Plates for Boilers"
"Hot-rolled Thin Plates and Strips of Carbon Structural Steel and Low-alloy Structural Steel"
"Hot-rolled Thick Plates and Wide Strips of Carbon Structural Steel"
"Hot-rolled Stainless Steel Plates"
"Heat-resistant Steel Plates"
"Stainless Composite Steel Plates"
"Non-ferrous Metal Structural Steel Plates for Conveying Fluids" Seamless steel pipe》
《Seamless stainless steel pipe for boilers and heat exchangers》《Seamless stainless steel pipe for fluid transportation》GB/T14976
GB6479
GB3087
GB5310
GB9948
GB3092
JB4726
JB4727
JB4728
JB4733
HG20537
《Seamless high-pressure steel pipe for fertilizer equipment》
《Seamless steel pipe for low and medium pressure boilers》||tt ||《Seamless steel pipe for high pressure boiler》
《Seamless steel pipe for petroleum cracking》
《Welded steel pipe for low pressure fluid transportation》
《Carbon steel and low alloy steel forgings for pressure vessels》《Carbon steel and low alloy steel forgings for low temperature pressure vessels》《Stainless steel forgings for pressure vessels》
《Explosive stainless steel composite steel plate for pressure vessels》《Austenitic stainless steel welded steel pipe》
3.0.2 Steel for pressure vessels shall comply with the requirements of GB150《Steel Pressure Vessels》, and the selection of steel shall be subject to the supervision of the《Technical Supervision Regulations for Safety of Pressure Vessels》issued by the State Administration of Quality and Technical Supervision. 3.0.3 Steel for pressure components and non-pressure components directly welded to pressure components must be accompanied by the steel quality certificate of the steel mill (or a copy, the copy should be stamped with the seal of the supply department). The following items should be listed on the steel quality certificate: furnace (tank) number, batch number;
Specifications:
Standard and measured chemical composition;
The specified mechanical properties, process properties and other performance requirements and measured data or qualified conditions guaranteed by the steel standards or technical conditions: supply status;
Other items specified in the supply contract or agreement; Steels for other non-pressure components should also have steel quality certificates (or copies). 3.0.4 If the data in the steel quality certificate (or copy) is incomplete or does not fully include the technical requirements specified in Chapter 5 of this standard, the equipment manufacturing department shall re-test or make up according to the steel standards and the requirements of this standard, and the materials can only be put into use after they are qualified. 3.0.5 In addition to the steel grade and standard, the design unit shall indicate the grade and other marks of the steel on the drawings or technical documents. If necessary, the drawings and technical documents shall also indicate the following additional requirements for steel: 1 Items in the steel standard that are guaranteed according to the requirements of the buyer; 2 Items in the steel standard that are agreed upon by the supply and demand parties; 3 Other additional requirements.
3.0.6 For steel standards (national standards, industry standards) and grades not listed in this standard, they can also be selected for design if they meet the following conditions at the same time:
1 According to the purpose, it is evaluated that the material performance and technical requirements are equivalent to or higher than the steel standards listed in this standard, and can meet the corresponding technical requirements of this standard;
2 Agree with the equipment technical person in charge of the design unit; 3 If necessary, it needs to be approved by the safety supervision agency. 3.0.7 For the use of new steel grades not listed in this standard, steel produced according to foreign standards, steel substitution during construction, etc., they shall comply with the provisions of the relevant provisions of GB150 and this standard respectively. Other situations beyond this standard (such as the use of steel beyond the provisions of this standard, the selection of higher mechanical properties, etc.) should be analyzed specifically, supplemented by necessary tests or inspections, and handled in accordance with Article 3.0.6.
4 General principles of material selection
4.0.1 The selection of steel for chemical containers must consider the operating conditions of the equipment (such as design pressure, design temperature, characteristics of the medium), the welding performance of the material, the cold and hot processing performance, the heat treatment and the structure of the container. 4.0.2 The selection of steel for chemical containers must consider economic rationality on the premise of meeting Article 4.0.1. Under normal circumstances, the following regulations are economically reasonable.
1 When the required steel plate thickness is less than 8mm, between carbon steel and low-alloy high-strength steel, carbon steel plates should be used as much as possible (except for multi-layer containers);
2 In situations where stiffness or structural design is the main consideration, ordinary carbon steel should be used as much as possible. In the occasions where strength design is the main purpose, Q235A, Q235B, 20R (20g), 16MnR and other steel plates should be selected in turn according to the use restrictions such as pressure, temperature, and medium; 3 When the required stainless steel thickness is greater than 12mm, lining, composite, surfacing and other structural forms should be used as much as possible; 4 Stainless steel should not be used as heat-resistant steel with a design temperature of 500℃ or less as much as possible 5 Pearlite heat-resistant steel should not be used as heat-resistant steel with a design temperature of 350℃ or less as much as possible. When pearlite heat-resistant steel must be used for heat-resistant or hydrogen-resistant purposes, the types and specifications of steel should be reduced and merged as much as possible. 4.0.3 The selection objects of various types of steel listed in this article are the guiding principles of design and should be implemented under normal circumstances. 1 Carbon steel is used for normal pressure and low-pressure vessels with less corrosive media, medium-pressure vessels with small wall thickness, forgings, pressure-bearing steel pipes, non-pressure components and other occasions where the wall thickness is determined by rigidity or structural factors. 2 Low alloy high strength steel is used for pressure vessels with less corrosive media and thicker walls (≥8mm). 3 Pearlite heat resistant steel is used to resist high temperature hydrogen or hydrogen sulfide corrosion, or heat resistant steel for pressure vessels with a design temperature of 350-650°C. 4 Stainless steel is used for heat resistant or low temperature steel with high corrosive media (electrochemical corrosion, chemical corrosion), anti-iron ion pollution, or design temperature greater than 500°C or design temperature less than -100°C. 5 Austenitic stainless steel that does not contain stabilizing elements and has a carbon content greater than 0.03% should not be used in environments that may cause intergranular corrosion of stainless steel when it needs to be welded or hot processed at above 400°C. 4.0.4 In addition to meeting the requirements of relevant steel standards, steel materials shall also meet the technical requirements, use restrictions and scope of this standard for steel materials.
4.0.5 Steel used as standard parts of chemical equipment such as equipment flanges, pipe flanges, pipe fittings, manholes, liquid level gauges, etc. shall comply with the technical requirements of national standards and industry standards for relevant parts (any conflicts with the corresponding provisions of this standard shall not be subject to the restrictions of this standard).
① When 20R is difficult to supply, 20g can be used. 33
5 Technical requirements for steel
5.1 General technical requirements
5.1.1 Steel for pressure vessels and pressure components (plates, pipes, profiles, forgings, castings) shall be smelted in open hearth, electric furnace or oxygen converter. 5.1.2 The steel used for the main pressure-bearing components of high-temperature pressure vessels that meet the following conditions at the same time shall be re-tested for the yield strength value at the design temperature according to the furnace number, and the value shall not be less than 1.6 times (1.5 times for austenitic steel) of the corresponding allowable stress value: 1 Design temperature greater than 300℃;
2 Design pressure greater than or equal to 1.6MPa;
3 Steel thickness greater than or equal to 20mm:
4 The main section of the steel is mainly to bear the primary film stress, and its thickness depends on the result of the strength calculation. 5.1.3 When austenitic stainless steel is used in an environment that may cause intergranular corrosion①, the intergranular corrosion tendency test shall be carried out in accordance with CB4334.1~4334.5 "Test Method for Intergranular Corrosion of Stainless Steel Products". 1 Except for the following cases, austenitic stainless steel should be tested for intergranular corrosion tendency with samples in the as-supplied state: (1) Steel for welded structures (including weld repair) should be tested with samples that have been sensitized in the as-supplied state, and welded joints should be tested with samples in the welded state;
(2) Austenitic stainless steel that needs to be heated to a temperature above 400°C (except for solution treatment or stabilization treatment) during manufacturing or use should be tested with samples that have been sensitized in the as-supplied state. The sensitization treatment system is generally 650°C for 0.5 to 2 hours. Duplex stainless steel is 650°C for half an hour. 2 The selection of the test method for intergranular corrosion tendency of austenitic stainless steel and its qualification requirements can be formulated according to the following provisions: (1) Austenitic stainless steel used in nitric acid with a temperature greater than or equal to 60°C and a concentration greater than or equal to 5%, and stainless steel specially used for concentrated nitric acid, shall be tested in accordance with GB4334.3 "Stainless Steel 65% Nitric Acid Corrosion Test Method", and the average corrosion rate of five cycles or the maximum corrosion rate of three cycles shall not exceed 0.6 g/m2h (or equivalent to 0.6 mm/year). The sample state can be in the use state or sensitized state.
(2) Non-molybdenum-containing austenitic stainless steel (such as 0Cr18Ni10Ti.00Cr19Ni10, 0Cr18Ni9 and similar steels): General requirements: According to GB4334.5 "Stainless Steel Sulfuric Acid-Copper Sulfate Corrosion Test Method", after the bending test, there shall be no intergranular corrosion cracks on the surface of the sample.
Higher requirements: According to GB4334.2 "Stainless Steel Sulfuric Acid-Ferrous Sulfate Corrosion Test Method", the average corrosion rate shall not exceed 1.1 g/m2h. It can also be tested by 65% nitric acid method according to GB4334.3, and its qualified requirements are the same as those of 5.1.3, paragraph 2 (1). (3) Contains austenitic stainless steel (such as 0Cr18Ni12Mo2Ti, 00Cr17Ni14Mo2 and similar steels). General requirements: According to GB4334.5 "Stainless steel sulfuric acid-copper sulfate corrosion test method", after the bending test, there shall be no intergranular corrosion cracks on the surface of the sample.
Higher requirements: According to GB4334.4 "Stainless steel nitric acid-hydrofluoric acid corrosion test method", the corrosion ratio shall not exceed 1.5. ① "The environment that may cause intergranular corrosion" must be an electrochemical corrosion environment with electrolytes. The electrolytes that may cause intergranular corrosion of austenitic stainless steel are mainly acidic media, such as industrial acetic acid, formic acid, chromic acid, lactic acid, nitric acid, oxalic acid, phosphoric acid, hydrochloric acid, sulfuric acid, sulfuric acid, ammonium carbamate, etc. For details, see "Corrosion Data Chart" compiled by GA. Nelson, National Chemical Equipment Design Technology Center, 1974 edition. Generally, pure alcohol, aldehyde, ketone, ether, benzene, phenol, alkane, gasoline and other solutions and gaseous media will not cause intergranular corrosion to austenitic stainless steel. 34
According to the sulfuric acid-ferrous sulfate (GB4334.2) method, the average corrosion rate should not be greater than 1.1 g/m2·hour. (4) When there are special requirements for the medium, intergranular corrosion tests other than those specified above can be carried out and corresponding qualification requirements can be specified. 3 The 10% oxalic acid method (GB4334.1) is allowed to be used as a screening test method for the 65% nitric acid method, sulfuric acid-copper sulfate (copper scraps) method, sulfuric acid-ferrous sulfate method, and nitric acid-hydrofluoric acid method. However, when used for screening of the 65% nitric acid method, it is not applicable to austenitic stainless steel containing Mo or Ti.
5.1.4 The allowable stress of austenitic stainless steel listed in GB150 "Steel Pressure Vessels" is applicable to austenitic stainless steel that meets general technical requirements. When the additional requirement is that the lower limit of carbon content is greater than or equal to 0.04%, rapid cooling and heat treatment at a temperature above 1050℃ is required, or the grain size of the steel is coarser than or equal to the 6-grade requirement, the higher high temperature allowable stress value (i.e. 304H, 316H, 321H) can be selected by referring to JIS B8270 or the first and second volumes of the first volume of ASME of the United States. 5.2 Steel Plate
5.2.1 When medium and thick hot-rolled steel plates with a maximum thickness negative deviation of 0.25 mm are used, the negative thickness deviation C of the steel plate may be ignored in the design calculation of the pressure vessel.
5.2.2 Steel plates supplied in accordance with GB6654 are guaranteed to have a negative deviation of 0.25mm in thickness. 5.2.3 When the thickness of the steel plate is less than 6mm, but low-carbon steel or low-alloy high-strength steel plates of container grade must be used, HP245 and HP345 steel plates produced in accordance with GB6653 "Welded Gas Cylinder Steel Plates" should be selected. 5.2.4 For containers with a design temperature greater than or equal to 0°C, 20g, 16Mng, 15MnVg, and 18MnMoNbg steel plates that meet the requirements of GB713 "Carbon Steel and Low-Alloy Steel Plates for Boilers" can be used equivalently to 20R, 16MnR, 15MnVR, and 18MnMoNbR steel plates that meet the requirements of GB6654.
5.2.5 Common thickness specifications for steel plates are shown in Table 5-1. Common thickness specifications should be used as much as possible in design. Table 5-1 Common thickness of steel plates
2, 3, 4, (5), 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 30, 32, 34, 36, 38, 40, 42, 46, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 Note: 5 mm is the common thickness of stainless steel plates.
5.2.6 Impact toughness requirements of steel plates
1 The following steel plates used for pressure vessels with a design temperature less than 0°C but greater than -20°C shall be subjected to low-temperature V-notch Charpy impact tests at the design temperature (transverse sampling, average value of three specimens in each group), and the impact energy shall meet the requirements of Table 5-2. Table 5-2
16MnR.15MnVR
15CrMoR
14Cr1MoR.12Cr2Mo1R
15MnVNR
18MnMoNbR、13MnNiMoNbR
(mm）
Design temperature（C）
<0≥-10
<-10,>-20
<0,≥-10
<-10,>-20
<0,>-20
0,≥ -10
<-10,>-20
<0,>-20
Impact energy of standard specimen (J)
Other small-sized impact tests that can be processed as thick as possible according to the thickness of the steel are allowed. The impact energy requirement is reduced in proportion to the width of the specimen. Ferritic steel plates with a thickness of 6mm or more for main pressure-bearing components with a design pressure greater than or equal to 1.6MPa or a design temperature less than 0℃ but greater than -20℃ should be subjected to room temperature V-notch Charpy impact toughness test (transverse sampling, average value of three specimens in each group), and the impact energy should at least reach the requirement of 27J (small-sized specimens are reduced in proportion). Steel plates for containers with extremely hazardous and highly hazardous media should also meet the above requirements. When the steel plate thickness is less than 6mm and the impact test cannot be carried out, steel plates for welded gas cylinders that comply with GB6653 should be used. 3 Ferritic steel plates with a thickness of 50 mm or more for the main pressure-bearing components of pressure vessels shall ensure that the V-notch Charpy impact energy (transverse) at a temperature of 17°C minus the water temperature of the hydraulic test is not less than the above requirements. 4 When conducting the Charpy impact toughness test (normal temperature or low temperature), the minimum value of a single specimen shall not be less than 70% of the corresponding mean value requirement. For those who can process standard 10mm×10mm×55mm specimens, small-sized impact specimens shall not be used. When the material thickness is too small to cut standard specimens, 7.5.5, 2.5mm×10mm×55mm small-sized specimens are allowed, and their impact energy requirements are 75%, 50%, and 25% of the corresponding standard specimens. 5 The longitudinal and transverse impact energy requirements of steel plates, when there is no other reliable basis, can be converted according to the following ratio: longitudinal test specimen: transverse test specimen = 1: 0.7
5.2.7 Nondestructive testing
1 Steel plates for the main pressure-bearing components of pressure vessels that meet any of the following conditions shall be subjected to ultrasonic testing in accordance with JB4730:
(1) 20R, 16MnR with a thickness greater than 30mm and other low-carbon steels with similar strength levels and chemical compositions and not higher than 16MnR Steel, carbon manganese steel plate;
(2) Other low alloy steel plates with a thickness greater than 25mm, low alloy steel plates for cryogenic pressure vessels with a thickness greater than 20mm;(3) Steel plates for inner tubes of multilayer vessels and single-layer high-pressure vessels with a design pressure greater than or equal to 10.0MPa (except austenitic steel plates), or steel plates supplied in the quenched and tempered state;(4) Ferritic steel plates with a thickness greater than or equal to 20mm and used in wet hydrogen sulfide corrosive environments with extremely or highly toxic media.
2 The ultrasonic flaw detection qualification level of steel plates is: 5.2.7, paragraph 1 (1), (2): Level II; 5.2.7, paragraph 1 (3), (4): Level 1. 3 Stainless steel composite steel plates for main pressure-bearing components of pressure vessels with a design pressure greater than or equal to 1.6MPa and stainless steel composite steel plates for heat exchanger tube sheets shall be ultrasonically inspected in accordance with GB7734 "Ultrasonic flaw detection method for composite steel plates". The composite plates for shells and heads shall be inspected along the grid lines with a spacing of 200mm, the 50mm area of the folded edge, and the 25mm area outside the edge of the predetermined opening. The composite plates for hot-pressed heads and high-pressure cylinders with a design pressure greater than or equal to 10.0MPa shall meet the requirements of Class II of GB7734; the composite plates for general cylinders shall meet the requirements of Class II. The composite plates for tube sheets shall be subjected to 100% ultrasonic flaw detection and meet the requirements of Class 1 of GB7734. 5.2.8 Heat treatment
1 The 20R, 16MnR steel plates with a thickness greater than 30mm and the 15MnVR steel plates with a thickness greater than 16mm for the main pressure-bearing components of pressure vessels shall be used in the normalized state. The 20R and 16MnR steel plates with a thickness greater than 50mm used to manufacture other pressure-bearing components (such as flanges, tube sheets, flat covers) shall also be normalized.
2Pearlite heat-resistant steel (such as 0.5Mo steel, 1YCr-0.5Mo steel, 2/4Cr1Mo steel) steel plates should be used in the annealed or normalized state. Pearlite heat-resistant steel plates that have been heat-treated should be considered whether they need to be reheat-treated based on the evaluation of the heat treatment process.
3Austenitic stainless steel should be used in the solid solution state or stabilized state (only for austenitic stainless steel with stabilizing elements). Austenitic stainless steel plates that have been heat-treated above 600℃ should be re-solution treated or stabilized when used in an intergranular corrosion environment.
4 For low-alloy high-strength steel plates used for the main pressure-bearing components of pressure vessels that meet the following requirements at the same time, the mechanical properties of the steel plates in the state of simulated stress relief heat treatment after welding shall be tested and meet the design requirements: (1) The design pressure is greater than or equal to 4.0MPa;
(2) The plate thickness is greater than or equal to 40mm;
(3) Stress relief heat treatment is performed after welding. 5.3 Steel
5.3.1 Steel pipes for pressure-bearing components can be produced by seamless or welding processes. When welded steel pipes produced by automatic arc welding or high-frequency welding are used for pressure-bearing components, they shall comply with the corresponding requirements of Article 6.4.3 of this standard. 5.3.2 For steel pipes (heat exchange tubes) such as shell and tube heat exchangers that need to be precisely matched with tube sheets, baffles, etc., the outer diameter and wall thickness dimensional accuracy shall not be lower than the requirements shown in Table 5-3.
Table 5-3 Accuracy requirements for heat exchange tubes
Steel pipe size (mm)
>30<51
The standards for steel pipes that meet the above-mentioned dimensional accuracy requirements are shown in Table 5-4. Table 5-4 Standards for steel pipes that meet the precision of heat exchange tubes Standard number
GB8163
GB3087
GB6479
GB9948
GB5310
GB13296
HG20537.2
Precision grade specified by the standard
Higher level of precision
Higher level of precision
General level
Ordinary level of precision
Higher level of precision
Should be specified when ordering
Should be specified when ordering
Should be specified when ordering
Not required to be specified when ordering
Should be specified when ordering
Not required to be specified when ordering4 For vessels with a design temperature greater than or equal to 0°C, 20g, 16Mng, 15MnVg, 18MnMoNbg steel plates that meet the requirements of GB713 "Carbon steel and low alloy steel plates for boilers" can be used equivalently to 20R, 16MnR, 15MnVR, 18MnMoNbR steel plates that meet the requirements of GB6654.
5.2.5 Common thickness specifications of steel plates are shown in Table 5-1. Common thickness specifications should be used as much as possible in design. Table 5-1 Common thickness of steel plates
2, 3, 4, (5), 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 30, 32, 34, 36, 38, 40, 42, 46, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 Note: 5 mm is the common thickness of stainless steel plates.
5.2.6 Impact toughness requirements of steel plates
1 The following steel plates used for pressure vessels with a design temperature less than 0°C but greater than -20°C shall be subjected to low-temperature V-notch Charpy impact tests at the design temperature (transverse sampling, average value of three specimens in each group), and the impact energy shall meet the requirements of Table 5-2. Table 5-2
16MnR.15MnVR
15CrMoR
14Cr1MoR.12Cr2Mo1R
15MnVNR
18MnMoNbR、13MnNiMoNbR
(mm）
Design temperature（C）
<0≥-10
<-10,>-20
<0,≥-10
<-10,>-20
<0,>-20
0,≥ -10
<-10,>-20
<0,>-20
Impact energy of standard specimen (J)
Other small-sized impact tests that can be processed as thick as possible according to the thickness of the steel are allowed. The impact energy requirement is reduced in proportion to the width of the specimen. Ferritic steel plates with a thickness of 6mm or more for main pressure-bearing components with a design pressure greater than or equal to 1.6MPa or a design temperature less than 0℃ but greater than -20℃ should be subjected to room temperature V-notch Charpy impact toughness test (transverse sampling, average value of three specimens in each group), and the impact energy should at least reach the requirement of 27J (small-sized specimens are reduced in proportion). Steel plates for containers with extremely hazardous and highly hazardous media should also meet the above requirements. When the steel plate thickness is less than 6mm and the impact test cannot be carried out, steel plates for welded gas cylinders that comply with GB6653 should be used. 3 Ferritic steel plates with a thickness of 50 mm or more for the main pressure-bearing components of pressure vessels shall ensure that the V-notch Charpy impact energy (transverse) at a temperature of 17°C minus the water temperature of the hydraulic test is not less than the above requirements. 4 When conducting the Charpy impact toughness test (normal temperature or low temperature), the minimum value of a single specimen shall not be less than 70% of the corresponding mean value requirement. For those who can process standard 10mm×10mm×55mm specimens, small-sized impact specimens shall not be used. When the material thickness is too small to cut standard specimens, 7.5.5, 2.5mm×10mm×55mm small-sized specimens are allowed, and their impact energy requirements are 75%, 50%, and 25% of the corresponding standard specimens. 5 The longitudinal and transverse impact energy requirements of steel plates, when there is no other reliable basis, can be converted according to the following ratio: longitudinal test specimen: transverse test specimen = 1:0.7
5.2.7 Nondestructive testing
1 Steel plates for the main pressure-bearing components of pressure vessels that meet any of the following conditions shall be subjected to ultrasonic testing in accordance with JB4730:
(1) 20R, 16MnR with a thickness greater than 30mm and other low-carbon steels with similar strength levels and chemical compositions and not higher than 16MnR Steel, carbon manganese steel plate;
(2) Other low alloy steel plates with a thickness greater than 25mm, low alloy steel plates for cryogenic pressure vessels with a thickness greater than 20mm;(3) Steel plates for inner tubes of multilayer vessels and single-layer high-pressure vessels with a design pressure greater than or equal to 10.0MPa (except austenitic steel plates), or steel plates supplied in the quenched and tempered state;(4) Ferritic steel plates with a thickness greater than or equal to 20mm and used in wet hydrogen sulfide corrosive environments with extremely or highly toxic media.
2 The ultrasonic flaw detection qualification level of steel plates is: 5.2.7, paragraph 1 (1), (2): Level II; 5.2.7, paragraph 1 (3), (4): Level 1. 3 Stainless steel composite steel plates for main pressure-bearing components of pressure vessels with a design pressure greater than or equal to 1.6MPa and stainless steel composite steel plates for heat exchanger tube sheets shall be ultrasonically inspected in accordance with GB7734 "Ultrasonic flaw detection method for composite steel plates". The composite plates for shells and heads shall be inspected along the grid lines with a spacing of 200mm, the 50mm area of the folded edge, and the 25mm area outside the edge of the predetermined opening. The composite plates for hot-pressed heads and high-pressure cylinders with a design pressure greater than or equal to 10.0MPa shall comply with the requirements of Class II of GB7734; the composite plates for general cylinders shall comply with the requirements of Class II. The composite plates for tube sheets shall be subjected to 100% ultrasonic flaw detection and meet the requirements of Class 1 of GB7734. 5.2.8 Heat treatment
1 The 20R, 16MnR steel plates with a thickness greater than 30mm and the 15MnVR steel plates with a thickness greater than 16mm for the main pressure-bearing components of pressure vessels shall be used in the normalized state. The 20R and 16MnR steel plates with a thickness greater than 50mm used to manufacture other pressure-bearing components (such as flanges, tube sheets, flat covers) shall also be normalized.
2Pearlite heat-resistant steel (such as 0.5Mo steel, 1YCr-0.5Mo steel, 2/4Cr1Mo steel) steel plates should be used in the annealed or normalized ten times36
state. Pearlite heat-resistant steel plates that have been heat-treated should be considered whether they need to be reheat-treated according to the evaluation of the hot working process.
3Austenitic stainless steel should be used in the solid solution state or stabilized (only for austenitic stainless steel with stabilizing elements). Austenitic stainless steel plates that have been heat-treated above 600℃ should be re-solution treated or stabilized when used in intergranular corrosion environments.
4 For low-alloy high-strength steel plates used for the main pressure-bearing components of pressure vessels that meet the following requirements at the same time, the mechanical properties of the steel plates in the state of simulated stress relief heat treatment after welding shall be tested and meet the design requirements: (1) The design pressure is greater than or equal to 4.0MPa;
(2) The plate thickness is greater than or equal to 40mm;
(3) Stress relief heat treatment is performed after welding. 5.3 Steel
5.3.1 Steel pipes for pressure-bearing components can be produced by seamless or welding processes. When welded steel pipes produced by automatic arc welding or high-frequency welding are used for pressure-bearing components, they shall comply with the corresponding requirements of Article 6.4.3 of this standard. 5.3.2 For steel pipes (heat exchange tubes) such as shell and tube heat exchangers that need to be precisely matched with tube sheets, baffles, etc., the outer diameter and wall thickness dimensional accuracy shall not be lower than the requirements shown in Table 5-3.
Table 5-3 Accuracy requirements for heat exchange tubes
Steel pipe size (mm)
>30<51
The standards for steel pipes that meet the above-mentioned dimensional accuracy requirements are shown in Table 5-4. Table 5-4 Standards for steel pipes that meet the precision of heat exchange tubes Standard number
GB8163
GB3087
GB6479
GB9948
GB5310
GB13296
HG20537.2
Precision grade specified by the standard
Higher level of precision
Higher level of precision
General level
Ordinary level of precision
Higher level of precision
Should be specified when ordering
Should be specified when ordering
Should be specified when ordering
Not required to be specified when ordering
Should be specified when ordering
Not required to be specified when ordering4 For vessels with a design temperature greater than or equal to 0°C, 20g, 16Mng, 15MnVg, 18MnMoNbg steel plates that meet the requirements of GB713 "Carbon steel and low alloy steel plates for boilers" can be used equivalently to 20R, 16MnR, 15MnVR, 18MnMoNbR steel plates that meet the requirements of GB6654.
5.2.5 Common thickness specifications of steel plates are shown in Table 5-1. Common thickness specifications should be used as much as possible in design. Table 5-1 Common thickness of steel plates
2, 3, 4, (5), 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 30, 32, 34, 36, 38, 40, 42, 46, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 Note: 5 mm is the common thickness of stainless steel plates.
5.2.6 Impact toughness requirements of steel plates
1 The following steel plates used for pressure vessels with a design temperature less than 0°C but greater than -20°C shall be subjected to low-temperature V-notch Charpy impact tests at the design temperature (transverse sampling, average value of three specimens in each group), and the impact energy shall meet the requirements of Table 5-2. Table 5-2
16MnR.15MnVR
15CrMoR
14Cr1MoR.12Cr2Mo1R
15MnVNR
18MnMoNbR、13MnNiMoNbR
(mm）
Design temperature（C）
<0≥-10
<-10,>-20
<0,≥-10
<-10,>-20
<0,>-20
0,≥ -10
<-10,>-20
<0,>-20
Impact energy of standard specimen (J)
Other small-sized impact tests that can be processed as thick as possible according to the thickness of the steel are allowed. The impact energy requirement is reduced in proportion to the width of the specimen. Ferritic steel plates with a thickness of 6mm or more for main pressure-bearing components with a design pressure greater than or equal to 1.6MPa or a design temperature less than 0℃ but greater than -20℃ should be subjected to room temperature V-notch Charpy impact toughness test (transverse sampling, average value of three specimens in each group), and the impact energy should at least reach the requirement of 27J (small-sized specimens are reduced in proportion). Steel plates for containers with extremely hazardous and highly hazardous media should also meet the above requirements. When the steel plate thickness is less than 6mm and the impact test cannot be carried out, steel plates for welded gas cylinders that comply with GB6653 should be used. 3 Ferritic steel plates with a thickness of 50 mm or more for the main pressure-bearing components of pressure vessels shall ensure that the V-notch Charpy impact energy (transverse) at a temperature of 17°C minus the water temperature of the hydraulic test is not less than the above requirements. 4 When conducting the Charpy impact toughness test (normal temperature or low temperature), the minimum value of a single specimen shall not be less than 70% of the corresponding mean value requirement. For those who can process standard 10mm×10mm×55mm specimens, small-sized impact specimens shall not be used. When the material thickness is too small to cut standard specimens, 7.5.5, 2.5mm×10mm×55mm small-sized specimens are allowed, and their impact energy requirements are 75%, 50%, and 25% of the corresponding standard specimens. 5 The longitudinal and transverse impact energy requirements of steel plates, when there is no other reliable basis, can be converted according to the following ratio: longitudinal test specimen: transverse test specimen = 1:0.7
5.2.7 Nondestructive testing
1 Steel plates for the main pressure-bearing components of pressure vessels that meet any of the following conditions shall be subjected to ultrasonic testing in accordance with JB4730:
(1) 20R, 16MnR with a thickness greater than 30mm and other low-carbon steels with similar strength levels and chemical compositions and not higher than 16MnR Steel, carbon manganese steel plate;
(2) Other low alloy steel plates with a thickness greater than 25mm, low alloy steel plates for cryogenic pressure vessels with a thickness greater than 20mm;(3) Steel plates for inner tubes of multilayer vessels and single-layer high-pressure vessels with a design pressure greater than or equal to 10.0MPa (except austenitic steel plates), or steel plates supplied in the quenched and tempered state;(4) Ferritic steel plates with a thickness greater than or equal to 20mm and used in wet hydrogen sulfide corrosive environments with extremely or highly toxic media.
2 The ultrasonic flaw detection qualification level of steel plates is: 5.2.7, paragraph 1 (1), (2): Level II; 5.2.7, paragraph 1 (3), (4): Level 1. 3 Stainless steel composite steel plates for main pressure-bearing components of pressure vessels with a design pressure greater than or equal to 1.6MPa and stainless steel composite steel plates for heat exchanger tube sheets shall be ultrasonically inspected in accordance with GB7734 "Ultrasonic flaw detection method for composite steel plates". The composite plates for shells and heads shall be inspected along the grid lines with a spacing of 200mm, the 50mm area of the folded edge, and the 25mm area outside the edge of the predetermined opening. The composite plates for hot-pressed heads and high-pressure cylinders with a design pressure greater than or equal to 10.0MPa shall comply with the requirements of Class II of GB7734; the composite plates for general cylinders shall comply with the requirements of Class II. The composite plates for tube sheets shall be subjected to 100% ultrasonic flaw detection and meet the requirements of Class 1 of GB7734. 5.2.8 Heat treatment
1 The 20R, 16MnR steel plates with a thickness greater than 30mm and the 15MnVR steel plates with a thickness greater than 16mm for the main pressure-bearing components of pressure vessels shall be used in the normalized state. The 20R and 16MnR steel plates with a thickness greater than 50mm used to manufacture other pressure-bearing components (such as flanges, tube sheets, flat covers) shall also be normalized.
2Pearlite heat-resistant steel (such as 0.5Mo steel, 1YCr-0.5Mo steel, 2/4Cr1Mo steel) steel plates should be used in the annealed or normalized ten times36
state. Pearlite heat-resistant steel plates that have been heat-treated should be considered whether they need to be reheat-treated according to the evaluation of the hot working process.
3Austenitic stainless steel should be used in the solid solution state or stabilized (only for austenitic stainless steel with stabilizing elements). Austenitic stainless steel plates that have been heat-treated above 600℃ should be re-solution treated or stabilized when used in intergranular corrosion environments.
4 For low-alloy high-strength steel plates used for the main pressure-bearing components of pressure vessels that meet the following requirements at the same time, the mechanical properties of the steel plates in the state of simulated stress relief heat treatment after welding shall be tested and meet the design requirements: (1) The design pressure is greater than or equal to 4.0MPa;
(2) The plate thickness is greater than or equal to 40mm;
(3) Stress relief heat treatment is performed after welding. 5.3 Steel
5.3.1 Steel pipes for pressure-bearing components can be produced by seamless or welding processes. When welded steel pipes produced by automatic arc welding or high-frequency welding are used for pressure-bearing components, they shall comply with the corresponding requirements of Article 6.4.3 of this standard. 5.3.2 For steel pipes (heat exchange tubes) such as shell and tube heat exchangers that need to be precisely matched with tube sheets, baffles, etc., the outer diameter and wall thickness dimensional accuracy shall not be lower than the requirements shown in Table 5-3.
Table 5-3 Accuracy requirements for heat exchange tubes
Steel pipe size (mm)
>30<51
The standards for steel pipes that meet the above-mentioned dimensional accuracy requirements are shown in Table 5-4. Table 5-4 Standards for steel pipes that meet the precision of heat exchange tubes Standard number
GB8163
GB3087
GB6479
GB9948
GB5310
GB13296
HG20537.2
Precision grade specified by the standard
Higher level of precision
Higher level of precision
General level
Ordinary level of precision
Higher level of precision
Should be specified when ordering
Should be specified when ordering
Should be specified when ordering
Not required to be specified when ordering
Should be specified when ordering
Not required to be specified when ordering5 Common thickness specifications of steel plates are shown in Table 5-1. Common thickness specifications should be used as much as possible in design. Table 5-1 Common thickness of steel plates
2, 3, 4, (5), 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 30, 32, 34, 36, 38, 40, 42, 46, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 Note: 5mm is the common thickness of stainless steel plates.
5.2.6 Impact toughness requirements of steel plates
1 The following steel plates used for pressure vessels with a design temperature less than 0℃ but greater than -20℃ shall be subjected to low-temperature V-notch Charpy impact test at the design temperature (transverse sampling, average value of three specimens in each group), and the impact energy shall meet the requirements of Table 5-2. Table 5-2
16MnR.15MnVR
15CrMoR
14Cr1MoR.12Cr2Mo1R
15MnVNR
18MnMoNbR、13MnNiMoNbR
(mm）
Design temperature（C）
<0≥-10
<-10,>-20
<0,≥-10
<-10,>-20
<0,>-20
0,≥ -10
<-10,>-20
<0,>-20
Impact energy of standard specimen (J)
Other small-sized impact tests that can be processed as thick as possible according to the thickness of the steel are allowed. The impact energy requirement is reduced in proportion to the width of the specimen. Ferritic steel plates with a thickness of 6mm or more for main pressure-bearing components with a design pressure greater than or equal to 1.6MPa or a design temperature less than 0℃ but greater than -20℃ should be subjected to room temperature V-notch Charpy impact toughness test (transverse sampling, average value of three specimens in each group), and the impact energy should at least reach the requirement of 27J (small-sized specimens are reduced in proportion). Steel plates for containers with extremely hazardous and highly hazardous media should also meet the above requirements. When the steel plate thickness is less than 6mm and the impact test cannot be carried out, steel plates for welded gas cylinders that comply with GB6653 should be used. 3 Ferritic steel plates with a thickness of 50 mm or more for the main pressure-bearing components of pressure vessels shall ensure that the V-notch Charpy impact energy (transverse) at a temperature of 17°C minus the water temperature of the hydraulic test is not less than the above requirements. 4 When conducting the Charpy impact toughness test (normal temperature or low temperature), the minimum value of a single specimen shall not be less than 70% of the corresponding mean value requirement. For those who can process standard 10mm×10mm×55mm specimens, small-sized impact specimens shall not be used. When the material thickness is too small to cut standard specimens, 7.5.5, 2.5mm×10mm×55mm small-sized specimens are allowed, and their impact energy requirements are 75%, 50%, and 25% of the corresponding standard specimens. 5 The longitudinal and transverse impact energy requirements of steel plates, when there is no other reliable basis, can be converted according to the following ratio: longitudinal test specimen: transverse test specimen = 1:0.7
5.2.7 Nondestructive testing
1 Steel plates for the main pressure-bearing components of pressure vessels that meet any of the following conditions shall be subjected to ultrasonic testing in accordance with JB4730:
(1) 20R, 16MnR with a thickness greater than 30mm and other low-carbon steels with similar strength levels and chemical compositions and not higher than 16MnR Steel, carbon manganese steel plate;
(2) Other low alloy steel plates with a thickness greater than 25mm, low alloy steel plates for cryogenic pressure vessels with a thickness greater than 20mm;(3) Steel plates for inner tubes of multilayer vessels and single-layer high-pressure vessels with a design pressure greater than or equal to 10.0MPa (except austenitic steel plates), or steel plates supplied in the quenched and tempered state;(4) Ferritic steel plates with a thickness greater than or equal to 20mm and used in wet hydrogen sulfide corrosive environments with extremely or highly toxic media.
2 The ultrasonic flaw detection qualification level of steel plates is: 5.2.7, paragraph 1 (1), (2): Level II; 5.2.7, paragraph 1 (3), (4): Level 1. 3 Stainless steel composite steel plates for main pressure-bearing components of pressure vessels with a design pressure greater than or equal to 1.6MPa and stainless steel composite steel plates for heat exchanger tube sheets shall be ultrasonically inspected in accordance with GB7734 "Ultrasonic flaw detection method for composite steel plates". The composite plates for shells and heads shall be inspected along the grid lines with a spacing of 200mm, the 50mm area of the folded edge, and the 25mm area outside the edge of the predetermined opening. The composite plates for hot-pressed heads and high-pressure cylinders with a design pressure greater than or equal to 10.0MPa shall comply with the requirements of Class II of GB7734; the composite plates for general cylinders shall comply with the requirements of Class II. The composite plates for tube sheets shall be subjected to 100% ultrasonic flaw detection and meet the requirements of Class 1 of GB7734. 5.2.8 Heat treatment
1 The 20R, 16MnR steel plates with a thickness greater than 30mm and the 15MnVR steel plates with a thickness greater than 16mm for the main pressure-bearing components of pressure vessels shall be used in the normalized state. The 20R and 16MnR steel plates with a thickness greater than 50mm used to manufacture other pressure-bearing components (such as flanges, tube sheets, flat covers) shall also be normalized. wwW.bzxz.Net
2Pearlite heat-resistant steel (such as 0.5Mo steel, 1YCr-0.5Mo steel, 2/4Cr1Mo steel) steel plates should be used in the annealed or normalized ten times36
state. Pearlite heat-resistant steel plates that have been heat-treated should be considered whether they need to be reheat-treated according to the evaluation of the hot working process.
3Austenitic stainless steel should be used in the solid solution state or stabilized (only for austenitic stainless steel with stabilizing elements). Austenitic stainless steel plates that have been heat-treated above 600℃ should be re-solution treated or stabilized when used in intergranular corrosion environments.
4 For low-alloy high-strength steel plates used for the main pressure-bearing components of pressure vessels that meet the following requirements at the same time, the mechanical properties of the steel plates in the state of simulated stress relief heat treatment after welding shall be tested and meet the design requirements: (1) The design pressure is greater than or equal to 4.0MPa;
(2) The plate thickness is greater than or equal to 40mm;
(3) Stress relief heat treatment is performed after welding. 5.3 Steel
5.3.1 Steel pipes for pressure-bearing components can be produced by seamless or welding processes. When welded steel pipes produced by automatic arc welding or high-frequency welding are used for pressure-bearing components, they shall comply with the corresponding requirements of Article 6.4.3 of this standard. 5.3.2 For steel pipes (heat exchange tubes) such as shell and tube heat exchangers that need to be precisely matched with tube sheets, baffles, etc., the outer diameter and wall thickness dimensional accuracy shall not be lower than the requirements shown in Table 5-3.
Table 5-3 Accuracy requirements for heat exchange tubes
Steel pipe size (mm)
>30<51
The standards for steel pipes that meet the above-mentioned dimensional accuracy requirements are shown in Table 5-4. Table 5-4 Standards for steel pipes that meet the precision of heat exchange tubes Standard number
GB8163
GB3087
GB6479
GB9948
GB5310
GB13296
HG20537.2
Precision grade specified by the standard
Higher level of precision
Higher level of precision
General level
Ordinary level of precision
Higher level of precision
Should be specified when ordering
Should be specified when ordering
Should be specified when ordering
Not required to be specified when ordering
Should be specified when ordering
Not required to be specified when ordering5 Common thickness specifications of steel plates are shown in Table 5-1. Common thickness specifications should be used as much as possible in design. Table 5-1 Common thickness of steel plates
2, 3, 4, (5), 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 30, 32, 34, 36, 38, 40, 42, 46, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 Note: 5mm is the common thickness of stainless steel plates.
5.2.6 Impact toughness requirements of steel plates
1 The following steel plates used for pressure vessels with a design temperature less than 0℃ but greater than -20℃ shall be subjected to low-temperature V-notch Charpy impact test at the design temperature (transverse sampling, average value of three specimens in each group), and the impact energy shall meet the requirements of Table 5-2. Table 5-2
16MnR.15MnVR
15CrMoR
14Cr1MoR.12Cr2Mo1R
15MnVNR
18MnMoNbR、13MnNiMoNbR
(mm）
Design temperature（C）
<0≥-10
<-10,>-20
<0,≥-10
<-10,>-20
<0,>-20
0,≥ -10
<-10,>-20
<0,>-20
Impact energy of standard specimen (J)
Other small-sized impact tests that can be processed as thick as possible according to the thickness of the steel are allowed. The impact energy requirement is reduced in proportion to the width of the specimen. Ferritic steel plates with a thickness of 6mm or more for main pressure-bearing components with a design pressure greater than or equal to 1.6MPa or a design temperature less than 0℃ but greater than -20℃ should be subjected to room temperature V-notch Charpy impact toughness test (transverse sampling, average value of three specimens in each group), and the impact energy should at least reach the requirement of 27J (small-sized specimens are reduced in proportion). Steel plates for containers with extremely hazardous and highly hazardous media should also meet the above requirements. When the steel plate thickness is less than 6mm and the impact test cannot be carried out, steel plates for welded gas cylinders that comply with GB6653 should be used. 3 Ferritic steel plates with a thickness of 50 mm or more for the main pressure-bearing components of pressure vessels shall ensure that the V-notch Charpy impact energy (transverse) at a temperature of 17°C minus the water temperature of the hydraulic test is not less than the above requirements. 4 When conducting the Charpy impact toughness test (normal temperature or low temperature), the minimum value of a single specimen shall not be less than 70% of the corresponding mean requirement. For those who can process standard 10mm×10mm×55mm specimens, small-sized impact specimens shall not be used. When the material thickness is too small to cut standard specimens, 7.5.5, 2.5mm×10mm×55mm small-sized specimens are allowed, and their impact energy requirements are 75%, 50%, and 25% of the corresponding standard specimens. 5 The longitudinal and transverse impact energy requirements of steel plates, when there is no other reliable basis, can be converted according to the following ratio: longitudinal test specimen: transverse test specimen = 1:0.7
5.2.7 Nondestructive testing
1 Steel plates for the main pressure-bearing components of pressure vessels that meet any of the following conditions shall be subjected to ultrasonic testing in accordance with JB4730:
(1) 20R, 16MnR with a thickness greater than 30mm and other low-carbon steels with similar strength levels and chemical compositions and not higher than 16MnR Steel, carbon manganese steel plate;
(2) Other low alloy steel plates with a thickness greater than 25mm, low alloy steel plates for cryogenic pressure vessels with a thickness greater than 20mm;(3) Steel plates for inner tubes of multilayer vessels and single-layer high-pressure vessels with a design pressure greater than or equal to 10.0MPa (except austenitic steel plates), or steel plates supplied in the quenched and tempered state;(4) Ferritic steel plates with a thickness greater than or equal to 20mm and used in wet hydrogen sulfide corrosive environments with extremely or highly toxic media.
2 The ultrasonic flaw detection qualification level of steel plates is: 5.2.7, paragraph 1 (1), (2): Level II; 5.2.7, paragraph 1 (3), (4): Level 1. 3 Stainless steel composite steel plates for main pressure-bearing components of pressure vessels with a design pressure greater than or equal to 1.6MPa and stainless steel composite steel plates for heat exchanger tube sheets shall be ultrasonically inspected in accordance with GB7734 "Ultrasonic flaw detection method for composite steel plates". The composite plates for shells and heads shall be inspected along the grid lines with a spacing of 200mm, the 50mm area of the folded edge, and the 25mm area outside the edge of the predetermined opening. The composite plates for hot-pressed heads and high-pressure cylinders with a design pressure greater than or equal to 10.0MPa shall comply with the requirements of Class II of GB7734; the composite plates for general cylinders shall comply with the requirements of Class II. The composite plates for tube sheets shall be subjected to 100% ultrasonic flaw detection and meet the requirements of Class 1 of GB7734. 5.2.8 Heat treatment
1 The 20R, 16MnR steel plates with a thickness greater than 30mm and the 15MnVR steel plates with a thickness greater than 16mm for the main pressure-bearing components of pressure vessels shall be used in the normalized state. The 20R and 16MnR steel plates with a thickness greater than 50mm used to manufacture other pressure-bearing components (such as flanges, tube sheets, flat covers) shall also be normalized.
2Pearlite heat-resistant steel (such as 0.5Mo steel, 1YCr-0.5Mo steel, 2/4Cr1Mo steel) steel plates should be used in the annealed or normalized state. Pearlite heat-resistant steel plates that have been heat-treated should be considered whether they need to be reheat-treated based on the evaluation of the heat treatment process.
3Austenitic stainless steel should be used in the solid solution state or stabilized state (only for austenitic stainless steel with stabilizing elements). Austenitic stainless steel plates that have been heat-treated above 600℃ should be re-solution treated or stabilized when used in an intergranular corrosion environment.
4 For low-alloy high-strength steel plates used for the main pressure-bearing components of pressure vessels that meet the following requirements at the same time, the mechanical properties of the steel plates in the state of simulated stress relief heat treatment after welding shall be tested and meet the design requirements: (1) The design pressure is greater than or equal to 4.0MPa;
(2) The plate thickness is greater than or equal to 40mm;
(3) Stress relief heat treatment is performed after welding. 5.3 Steel
5.3.1 Steel pipes for pressure-bearing components can be produced by seamless or welding processes. When welded steel pipes produced by automatic arc welding or high-frequency welding are used for pressure-bearing components, they shall comply with the corresponding requirements of Article 6.4.3 of this standard. 5.3.2 For steel pipes (heat exchange tubes) such as shell and tube heat exchangers that need to be precisely matched with tube sheets, baffles, etc., the outer diameter and wall thickness dimensional accuracy shall not be lower than the requirements shown in Table 5-3.
Table 5-3 Accuracy requirements for heat exchange tubes
Steel pipe size (mm)
>30<51
The standards for steel pipes that meet the above-mentioned dimensional accuracy requirements are shown in Table 5-4. Table 5-4 Standards for steel pipes that meet the precision of heat exchange tubes Standard number
GB8163
GB3087
GB6479
GB9948
GB5310
GB13296
HG20537.2
Precision grade specified by the standard
Higher level of precision
Higher level of precision
General level
Ordinary level of precision
Higher level of precision
Should be specified when ordering
Should be specified when ordering
Should be specified when ordering
Not required to be specified when ordering
Should be specified when ordering
Not required to be specified when ordering>-20
Impact energy of standard specimen (J)
Other small-sized impact tests that are as thick as possible according to the thickness of the steel are allowed. The impact energy requirements are reduced in proportion to the width of the specimen. 2 Ferritic steel plates with a thickness of 6mm or more for main pressure-bearing components with a design pressure of 1.6MPa or more or a design temperature of less than 0℃ but greater than -20℃ shall be subjected to a room temperature V-notch Charpy impact toughness test (transverse sampling, the average value of three specimens in each group), and the impact energy shall at least reach the requirement of 27J (small-sized specimens shall be reduced in proportion). Steel plates for containers with extremely hazardous and highly hazardous media shall also meet the above requirements. When the thickness of the steel plate is less than 6mm and the impact test cannot be carried out, steel plates for welded gas cylinders that comply with GB6653 shall be used. 3 Ferritic steel plates with a thickness of 50mm or more for main pressure-bearing components of pressure vessels shall ensure that the V-notch Charpy impact energy (transverse) at a tempera
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