Some standard content:
GB17258—1998
This standard is compiled on the basis of the former internal standard of the general machinery industry of the Ministry of Machinery and Electronics, JB/TQ814-89, "Specifications for Compressed Natural Gas High-Pressure Cylinders for Automobiles".
The important changes of this standard to JB/TQ814--89 are as follows: the nominal working pressure of 25MPa is cancelled; the volume series and diameter series are increased; manganese steel is cancelled and chromium-molybdenum steel is used in all materials; the wall thickness is calculated using the Mises formula and the upper limit is set for the tensile strength; the volume deformation rate of the burst test is cancelled; and the burst safety factor is revised. References of this standard: GB5099 "Seamless Steel Cylinders"; Chapter 49 of the United States Federal Regulations, 571.304 "Compressed Natural Gas Fuel Container Integrity" (1996) and ISO/CD11439 "High Pressure Cylinders for the On-board Storage of Natural Gas as a Fuel for Vehicles" (1996). Appendix A of this standard is the appendix of the standard. This standard is proposed by the Ministry of Labor of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Gas Cylinders. This standard was drafted by Beijing Tianhai Industrial Co., Ltd. The main drafters of this standard are Qiu Changjian and Wu Ruyuan. 141
1 Fanquan
National Standard of the People's Republic of China
Compressed Natural Gas Cylinders for Automobiles
Steel cylinders for the on-board of compressednatural gas us a fuel for vehiclesG 17258 - 1998
This standard specifies the types and parameters, technical requirements, test methods, inspection rules, marking, coating, packaging, transportation and storage of compressed natural gas cylinders for automobiles (hereinafter referred to as cylinders). This standard is applicable to the design and manufacture of cylinders with a nominal working pressure of 16~20MPa (the pressure in this standard refers to the gauge pressure), a nominal volume of 30~120L, and an operating temperature of -50C~60℃. Steel cylinders manufactured in accordance with this standard are only allowed to be filled with natural gas as fuel that meets the relevant standards and has a moisture content of no more than 8mz and a hydrogen sulfide content of no more than 20mg per standard cubic meter after dehydration, desulfurization and light oil removal. This standard does not apply to gas storage cylinders used in compressed natural gas filling stations, nor does it apply to composite gas cylinders. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB222--84 Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products GB223.1-81 Determination of carbon content in steel and alloys GB223.2-81 Determination of sulfur content in steel and alloys Determination of phosphorus content by diantipyryl methane phosphomolybdenum gravimetric method GB223.3--88 Chemical analysis methods for steel and alloys GB223.4-88 Chemical analysis methods for steel and alloys Determination of manganese content by ammonium nitrate oxidation volumetric method GB223.5-88 Chemical analysis methods for steel and alloys Determination of silicon content by oxalic acid-ferrous sulfate silicon molybdenum blue photometric method GB/T223.6-94 Chemical analysis methods for steel and alloys Determination of turnover content by neutralization titration method GB223.7-81 Determination of iron content in alloys and iron powder GB224-87 Determination of decarburization depth in steel GB 226-91 GB 228—87
Method for acid etching test of macrostructure and defects of steelMethod for tensile test of metals
GB/T 22994
GB 230—91
GB 231-84
GB 232--88
Method for Charpy notched impact test of metals
Method for Rockwell hardness test of metals
Method for Brinell hardness test of metals
Method for bending test of metals
GB 1979--80
GB 5777—86
GB 6397--86
GB 7144--86
Structural steel macrostructure defect rating chart
Ultrasonic flaw detection method for seamless steel pipe
Metal tensile test specimen
Color marking for gas cylinders
GB8163-87 Seamless steel pipe for conveying fluids
Approved by the State Administration of Technical Supervision on March 20, 1998 142
Implemented on October 1, 1998
GB8335-1998 Special thread for gas cylinders
GB 17258—1998
GB/T8336—1998 Thread gauge for gas cylindersGB/T9251—1997 Hydrostatic test method for gas cylindersGB9252-88 Fatigue test method for gas cylinders
GB/T12606—90 Magnetic flux leakage detection method for steel tubes and round steel barsGB12137-89 Gas tightness test method for gas cylindersGB/T13298—91 Metal microstructure inspection methodGB/T13299—91 Microstructure assessment method for steelFlattening test method for seamless gas cylinders
GB13440—92
GB 13447—92
Steel for seamless gas cylinders
GB 15385—94
Test method for hydraulic bursting of gas cylinders
JB4730--94 Nondestructive testing of pressure vessels
YB/T5148-93 Method for determination of average grain size of metals 3 Terms and symbols
This standard adopts the following definitions.
3.1 Nominal working pressure
The limited filling pressure of the cylinder at the reference temperature (20°C). 3.2 Yield stress
For the tensile test of the material specimen, the yield point or lower yield point is taken if there is obvious yield phenomenon; if there is no obvious yield phenomenon, the yield strength is taken. 3.3 Measured tensile strength
The actual tensile strength value measured in accordance with 6.3.2 of this standard. 3.4 Batch
refers to the limited number of steel cylinders that adopt the same design conditions, have the same nominal diameter, design wall thickness, are made of the same furnace steel, are made by the same manufacturing method, and are continuously heat treated according to the same heat treatment specification. 3.5 Stress concentration factor
The ratio of the local maximum stress in a certain part of the steel cylinder to the membrane stress of the cylinder body. 3.6 Symbols
Outer diameter of cylinder barrel, mm;
D—diameter of bend core in cold bending test, mm; H,r,Si,S2,Sg--—end structure dimensions, mm; P,—water pressure test pressure, MPa;
P,—service pressure during bursting test, MPa; S—
designed wall thickness of cylinder barrel, mm,
actually measured average wall thickness of cylinder barrel, mm;
distance between pressure heads in flattening test, mm;
nominal water volume, L;
original thickness of arc-shaped flat specimen, mm;
b. - Original width of flat specimen, mm; www.bzxz.net
d--circumferential tear width of the rupture, mm;
Original gauge length of specimen, mm;
Impact toughness value, J/cm2;
0--elongation, %;
GB 17258-1998
a. ——Guaranteed value of yield stress of bottle body material after heat treatment, N/mm2; dea
-Measured value of yield stress, N/mm2;
-Guaranteed value of tensile strength of bottle body material after heat treatment, N/mm2; Oba-Measured value of tensile strength, N/mm2. 4 Types and parameters
4.1 The structure of steel cylinder body shall generally conform to the type shown in Figure 1. Figure 1 Steel cylinder body structure type
4.2 The nominal working pressure of the steel cylinder shall be 16MPa or 20MPa. The nominal water volume and nominal outer diameter shall generally comply with the provisions of Table 1. Table 1 Water volume and outer diameter of steel cylinders
Nominal water volume V
Nominal outer diameter D.
4.3 The cylinder model consists of the following parts:
3040506070
8090100120
219229232245
267273 335425
Type A or B or C
Nominal outer diameter, mm
Nominal water volume, L
Nominal working pressure, MPa
Compressed natural gas cylinders for automobiles
Type A
Type B
Type C
Allowable deviation, %
Model example: For a cylinder with a nominal working pressure of 20MPa, a nominal water volume of 60L, a nominal outer diameter of 229 and a structural type of A, its model is marked as "CNP20-60-229A". 144
5 Technical requirements
5.1 General provisions for cylinder materials
GB 17258—1998
5.1.1 The body material should be non-aging killed steel smelted in alkaline open-hearth furnace, electric furnace or oxygen-blown alkaline converter. 5.1.2 The steel grade should be high-quality chromium-molybdenum steel.
5.1.3 The body material must comply with the provisions of the corresponding national standards or industry standards and have a quality certificate. The cylinder manufacturer should conduct various verification analyses according to the furnace number.
5.1.4 The body material should have good low-temperature impact resistance. 5.1.5 The chemical composition of the body material is limited in Table 2. The allowable deviation of the chemical composition shall comply with the provisions of Table 2 in GB222-84. Table 2 Chemical composition of bottle material
0. 17~ 0. 37 0. 40~0. 700. 80 ~ 1. 100. 15 ~ 0. 25s
5.2.1 The shape, size and allowable deviation of steel bars shall comply with the relevant provisions of GB13447. 5.2.2 Macrostructure
a) White spots, residual shrinkage cavities, stratification, bubbles, foreign matter and inclusions are not allowed; b) The central porosity shall not exceed level 1.5, and the segregation shall not exceed level 2.5. 5.3 Seamless steel pipe
5.3.1 The shape tolerance of steel pipes shall not be lower than that specified in GB8163. 0.030
5.3.2 The wall thickness deviation of steel pipes shall not exceed 22.5% of the minimum wall thickness. 5.3.3 Steel pipes shall be delivered by the steel mill after flaw detection one by one. The flaw detection shall be carried out in accordance with GB5777 or GB/T12606, and the qualified level shall be C5 or N5.5.4 Design
5.4.1 General provisions
5.4.1.1 Design of steel cylinders The internal pressure on which the design is based should be the water pressure test pressure. The water pressure test pressure should be 5/3 times the nominal working pressure. 5.4.1.2 The yield stress guarantee value selected for the design calculation of the bottle wall thickness shall not be greater than 85% of the tensile strength guarantee value. 5.4.1.3 The actual tensile strength of the material should be limited. The actual tensile strength of the cylinder body material should not be greater than 880N/mm2. 5.4.2 The simplified design wall thickness is calculated according to formula (1): S
and should also meet the requirements of formula (2):
5.4.3 End structure
5.4.3.1 There are four types of end structures
a) hemispherical with bottle mouth [see Figure 2a)]; b) hemispherical [see Figure 2b)];
c) dish-shaped [see Figure 2c)];
d) concave [see Figure 2d)].
e./1. 33 - 1. 3P
No/1.33+0.4Ph
（1）
：(2)
GB 17258 -1998
Figure 2 End structure type diagram
5.4.3.2 The dished end structure shall meet the following requirements: r ≥ 0. 075 D.;
H/D. ≥ 0.22; or H/D. ≥ 0.40
S ≥ 1.5 S; Si ≥ s
S2 ≥ 1.5 S; S2 ≥ S
Transition section
5.4.3.3 The nominal dimensions of the concave end shall meet the following requirements. If any of the parameters of the concave end cannot meet the following requirements, it shall be verified by a cyclic fatigue test.
S,=(2.0~2.6)S;
S2=(1.8~2.2)S;
S3 -(2.0~2.8)S;
r = (0.07~0.09)D.
H=(0.13～0.16)D. .
5.4.3.4 There should be a transition section between the ring shell and the cylinder at the concave end, and the connection between the transition section and the cylinder should be smooth. 5.4.3.5 The concave end shall be calculated according to the elastic finite element under the water pressure test pressure P, and shall be checked and adjusted within the tolerance value of the nominal size of the concave end; the stress concentration factor shall not be greater than 1.80. 5.4.3.6 The thickness of the mouth of the cylinder, starting from the thread groove, shall not be less than the design wall thickness of the cylinder, and shall ensure that it does not deform when subjected to the torque of the tightening valve and the additional external force of the riveted collar. 5.4.4 Annex
5.4.4.1 The cylinder valve shall be equipped with a safety pressure relief device, which shall be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, and the allowable deviation is ±5%. The operating temperature of the fusible plug is 100℃±5℃, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve shall meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose shall be marked on the cylinder valve. For example: M (manufacturing factory code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth shall ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《-General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and shall comply with the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the bottle body made by punching and stretching shall meet the specified design value, and the thickness of the end spherical shell and ring shell shall meet the design requirements.
5.5.1.5 The bottle body made by spinning of seamless steel pipe shall be subject to process assessment; there shall be no visible concave holes, wrinkles, bulges and oxide scale on the inner surface of the bottle body end; the defects of the end are allowed to be removed, but the design thickness of the end must be guaranteed; the end is not allowed to be repaired by welding. 5.5.2 Heat treatment
5.5.2.1 The steel cylinder shall be subjected to overall heat treatment, and the heat treatment shall be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature shall not be greater than 930℃, and the tempering temperature shall not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle body in the medium shall not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After the heat treatment of the bottle body, the hardness test and non-destructive testing shall be carried out one by one. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It shall be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It shall be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked by using standard or special measuring tool templates, the thickness of the bottle body shall be checked by using a thickness gauge, and the inner and outer surfaces of the bottle body shall be polished with special tools.
6.3 Determination of various performance indicators after heat treatment of the bottle body 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and the real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact specimens (3 pieces)
Flat tensile specimens (2 pieces))
Cold bending test (4 pieces)
Figure 3 Test sampling position diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; b) The shape of the tensile specimen preparation is shown in Figure 4;
c) The general requirements for the shape and size of the tensile specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.3 The body material must comply with the relevant national standards or industry standards and have a quality certificate. The cylinder manufacturer should conduct various verification analyses according to the furnace number.
5.1.4 The body material should have good low-temperature impact performance. 5.1.5 The chemical composition of the body material is limited in Table 2, and the allowable deviation of the chemical composition should comply with the provisions of Table 2 in GB222-84. Table 2 Chemical composition of the body material
0. 17~ 0. 37 0. 40~0. 700. 80 ~ 1. 100. 15 ~ 0. 25s
5.2.1 The shape, size and allowable deviation of the steel bar should comply with the relevant provisions of GB13447. 5.2.2 Macrostructure
a) White spots, residual shrinkage cavities, stratification, bubbles, foreign matter and inclusions are not allowed; b) The central looseness is not greater than 1.5 levels, and the segregation is not greater than 2.5 levels. 5.3 Seamless steel pipe
5.3.1 The shape tolerance of the steel pipe shall not be less than that specified in GB8163. 0.030
5.3.2 The wall thickness deviation of the steel pipe shall not exceed 22.5% of the minimum wall thickness. 5.3.3 The steel pipe shall be delivered by the steel mill after flaw detection one by one. The flaw detection shall be carried out in accordance with GB5777 or GB/T12606, and the qualified level shall be C5 or N5.5.4 Design
5.4.1 General provisions
5.4.1.1 The internal pressure on which the design of the cylinder is based shall be the water pressure test pressure. The water pressure test pressure shall be 5/3 times the nominal working pressure. 5.4.1.2 The yield stress guarantee value selected for the design calculation of the cylinder wall thickness shall not be greater than 85% of the tensile strength guarantee value. 5.4.1.3 The actual tensile strength of the material should be limited. The actual tensile strength of the cylinder body material should not be greater than 880N/mm2. 5.4.2 The design wall thickness of the simplified body is calculated according to formula (1): S
and should also meet the requirements of formula (2):
5.4.3 End structure
5.4.3.1 There are four types of end structures
a) hemispherical with bottle mouth [see Figure 2a)]; b) hemispherical [see Figure 2b)];
c) dish-shaped [see Figure 2c)];
d) concave [see Figure 2d)].
e./1. 33 - 1. 3P
No/1.33+0.4Ph
（1）
：(2)
GB 17258 -1998
Figure 2 End structure type diagram
5.4.3.2 The dished end structure shall meet the following requirements: r ≥ 0. 075 D.;
H/D. ≥ 0.22; or H/D. ≥ 0.40
S ≥ 1.5 S; Si ≥ s
S2 ≥ 1.5 S; S2 ≥ S
Transition section
5.4.3.3 The nominal dimensions of the concave end shall meet the following requirements. If any of the parameters of the concave end cannot meet the following requirements, it shall be verified by a cyclic fatigue test.
S,=(2.0~2.6)S;
S2=(1.8~2.2)S;
S3 -(2.0~2.8)S;
r = (0.07~0.09)D.
H=(0.13～0.16)D. .
5.4.3.4 There should be a transition section between the ring shell and the cylinder at the concave end, and the connection between the transition section and the cylinder should be smooth. 5.4.3.5 The concave end shall be calculated according to the elastic finite element under the water pressure test pressure P, and shall be checked and adjusted within the tolerance value of the nominal size of the concave end; the stress concentration factor shall not be greater than 1.80. 5.4.3.6 The thickness of the mouth of the cylinder, starting from the thread groove, shall not be less than the design wall thickness of the cylinder, and shall ensure that it does not deform when subjected to the torque of the tightening valve and the additional external force of the riveted collar. 5.4.4 Annex
5.4.4.1 The cylinder valve shall be equipped with a safety pressure relief device, which shall be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, and the allowable deviation is ±5%. The operating temperature of the fusible plug is 100℃±5℃, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve shall meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose shall be marked on the cylinder valve. For example: M (manufacturing factory code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth shall ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《-General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and shall comply with the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the bottle body made by punching and stretching shall meet the specified design value, and the thickness of the end spherical shell and ring shell shall meet the design requirements.
5.5.1.5 The bottle body made by spinning of seamless steel pipe shall be subject to process assessment; there shall be no visible concave holes, wrinkles, bulges and oxide scale on the inner surface of the bottle body end; the defects of the end are allowed to be removed, but the design thickness of the end must be guaranteed; the end is not allowed to be repaired by welding. 5.5.2 Heat treatment
5.5.2.1 The steel cylinder shall be subjected to overall heat treatment, and the heat treatment shall be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature shall not be greater than 930℃, and the tempering temperature shall not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle body in the medium shall not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After the heat treatment of the bottle body, the hardness test and non-destructive testing shall be carried out one by one. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It shall be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It shall be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked by using standard or special measuring tool templates, the thickness of the bottle body shall be checked by using a thickness gauge, and the inner and outer surfaces of the bottle body shall be polished with special tools.
6.3 Determination of various performance indicators after heat treatment of the bottle body 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and the real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact specimens (3 pieces)
Flat tensile specimens (2 pieces))
Cold bending test (4 pieces)
Figure 3 Test sampling position diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; b) The shape of the tensile specimen preparation is shown in Figure 4;
c) The general requirements for the shape and size of the tensile specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.3 The body material must comply with the relevant national standards or industry standards and have a quality certificate. The cylinder manufacturer should conduct various verification analyses according to the furnace number.
5.1.4 The body material should have good low-temperature impact performance. 5.1.5 The chemical composition of the body material is limited in Table 2, and the allowable deviation of the chemical composition should comply with the provisions of Table 2 in GB222-84. Table 2 Chemical composition of the body material
0. 17~ 0. 37 0. 40~0. 700. 80 ~ 1. 100. 15 ~ 0. 25s
5.2.1 The shape, size and allowable deviation of the steel bar should comply with the relevant provisions of GB13447. 5.2.2 Macrostructure
a) White spots, residual shrinkage cavities, stratification, bubbles, foreign matter and inclusions are not allowed; b) The central looseness is not greater than 1.5 levels, and the segregation is not greater than 2.5 levels. 5.3 Seamless steel pipe
5.3.1 The shape tolerance of the steel pipe shall not be less than that specified in GB8163. 0.030
5.3.2 The wall thickness deviation of the steel pipe shall not exceed 22.5% of the minimum wall thickness. 5.3.3 The steel pipe shall be delivered by the steel mill after flaw detection one by one. The flaw detection shall be carried out in accordance with GB5777 or GB/T12606, and the qualified level shall be C5 or N5.5.4 Design
5.4.1 General provisions
5.4.1.1 The internal pressure on which the design of the cylinder is based shall be the water pressure test pressure. The water pressure test pressure shall be 5/3 times the nominal working pressure. 5.4.1.2 The yield stress guarantee value selected for the design calculation of the cylinder wall thickness shall not be greater than 85% of the tensile strength guarantee value. 5.4.1.3 The actual tensile strength of the material should be limited. The actual tensile strength of the cylinder body material should not be greater than 880N/mm2. 5.4.2 The design wall thickness of the simplified body is calculated according to formula (1): S
and should also meet the requirements of formula (2):
5.4.3 End structure
5.4.3.1 There are four types of end structures
a) hemispherical with bottle mouth [see Figure 2a)]; b) hemispherical [see Figure 2b)];
c) dish-shaped [see Figure 2c)];
d) concave [see Figure 2d)].
e./1. 33 - 1. 3P
No/1.33+0.4Ph
（1）
：(2)
GB 17258 -1998
Figure 2 End structure type diagram
5.4.3.2 The dished end structure shall meet the following requirements: r ≥ 0. 075 D.;
H/D. ≥ 0.22; or H/D. ≥ 0.40
S ≥ 1.5 S; Si ≥ s
S2 ≥ 1.5 S; S2 ≥ S
Transition section
5.4.3.3 The nominal dimensions of the concave end shall meet the following requirements. If any of the parameters of the concave end cannot meet the following requirements, it shall be verified by a cyclic fatigue test.
S,=(2.0~2.6)S;
S2=(1.8~2.2)S;
S3 -(2.0~2.8)S;
r = (0.07~0.09)D.
H=(0.13～0.16)D. .
5.4.3.4 There should be a transition section between the ring shell and the cylinder at the concave end, and the connection between the transition section and the cylinder should be smooth. 5.4.3.5 The concave end shall be calculated according to the elastic finite element under the water pressure test pressure P, and shall be checked and adjusted within the tolerance value of the nominal size of the concave end; the stress concentration factor shall not be greater than 1.80. 5.4.3.6 The thickness of the mouth of the cylinder, starting from the thread groove, shall not be less than the design wall thickness of the cylinder, and shall ensure that it does not deform when subjected to the torque of the tightening valve and the additional external force of the riveted collar. 5.4.4 Annex
5.4.4.1 The cylinder valve shall be equipped with a safety pressure relief device, which shall be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, and the allowable deviation is ±5%. The operating temperature of the fusible plug is 100℃±5℃, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve shall meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose shall be marked on the cylinder valve. For example: M (manufacturing factory code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth shall ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《-General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and shall comply with the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the bottle body made by punching and stretching shall meet the specified design value, and the thickness of the end spherical shell and ring shell shall meet the design requirements.
5.5.1.5 The bottle body made by spinning of seamless steel pipe shall be subject to process assessment; there shall be no visible concave holes, wrinkles, bulges and oxide scale on the inner surface of the bottle body end; the defects of the end are allowed to be removed, but the design thickness of the end must be guaranteed; the end is not allowed to be repaired by welding. 5.5.2 Heat treatment
5.5.2.1 The steel cylinder shall be subjected to overall heat treatment, and the heat treatment shall be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature shall not be greater than 930℃, and the tempering temperature shall not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle body in the medium shall not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After the heat treatment of the bottle body, the hardness test and non-destructive testing shall be carried out one by one. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It shall be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It shall be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked by using standard or special measuring tool templates, the thickness of the bottle body shall be checked by using a thickness gauge, and the inner and outer surfaces of the bottle body shall be polished with special tools.
6.3 Determination of various performance indicators after heat treatment of the bottle body 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and the real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact specimens (3 pieces)
Flat tensile specimens (2 pieces))
Cold bending test (4 pieces)
Figure 3 Test sampling position diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; b) The shape of the tensile specimen preparation is shown in Figure 4;
c) The general requirements for the shape and size of the tensile specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.1 The internal pressure for the design of the steel cylinder shall be the water pressure test pressure. The water pressure test pressure shall be 5/3 times the nominal working pressure. 5.4.1.2 The yield stress guarantee value selected for the design calculation of the cylinder wall thickness shall not be greater than 85% of the tensile strength guarantee value. 5.4.1.3 The actual tensile strength of the material shall be limited. The actual tensile strength of the cylinder body material shall not be greater than 880N/mm2. 5.4.2 The simplified design wall thickness shall be calculated according to formula (1): S
and shall also meet the requirements of formula (2):
5.4.3 End structure
5.4.3.1 There are four types of end structures
a) hemispherical with bottle mouth [see Figure 2a)]; b) hemispherical [see Figure 2b)];
c) dish-shaped [see Figure 2c)];
d) concave [see Figure 2d)].
e./1. 33 - 1. 3P
No/1.33+0.4Ph
（1）
：(2)
GB 17258 -1998
Figure 2 End structure type diagram
5.4.3.2 The dished end structure shall meet the following requirements: r ≥ 0. 075 D.;
H/D. ≥ 0.22; or H/D. ≥ 0.40
S ≥ 1.5 S; Si ≥ s
S2 ≥ 1.5 S; S2 ≥ S
Transition section
5.4.3.3 The nominal dimensions of the concave end shall meet the following requirements. If any of the parameters of the concave end cannot meet the following requirements, it shall be verified by a cyclic fatigue test.
S,=(2.0~2.6)S;
S2=(1.8~2.2)S;
S3 -(2.0~2.8)S;
r = (0.07~0.09)D.
H=(0.13～0.16)D. .
5.4.3.4 There should be a transition section between the ring shell and the cylinder at the concave end, and the connection between the transition section and the cylinder should be smooth. 5.4.3.5 The concave end shall be calculated according to the elastic finite element under the water pressure test pressure P, and shall be checked and adjusted within the tolerance value of the nominal size of the concave end; the stress concentration factor shall not be greater than 1.80. 5.4.3.6 The thickness of the mouth of the cylinder, starting from the thread groove, shall not be less than the design wall thickness of the cylinder, and shall ensure that it does not deform when subjected to the torque of the tightening valve and the additional external force of the riveted collar. 5.4.4 Annex
5.4.4.1 The cylinder valve shall be equipped with a safety pressure relief device, which shall be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, and the allowable deviation is ±5%. The operating temperature of the fusible plug is 100℃±5℃, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve shall meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose shall be marked on the cylinder valve. For example: M (manufacturing factory code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth shall ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《-General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and shall comply with the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the bottle body made by punching and stretching shall meet the specified design value, and the thickness of the end spherical shell and ring shell shall meet the design requirements.
5.5.1.5 The bottle body made by spinning of seamless steel pipe shall be subject to process assessment; there shall be no visible concave holes, wrinkles, bulges and oxide scale on the inner surface of the bottle body end; the defects of the end are allowed to be removed, but the design thickness of the end must be guaranteed; the end is not allowed to be repaired by welding. 5.5.2 Heat treatment
5.5.2.1 The steel cylinder shall be subjected to overall heat treatment, and the heat treatment shall be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature shall not be greater than 930℃, and the tempering temperature shall not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle body in the medium shall not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After the heat treatment of the bottle body, the hardness test and non-destructive testing shall be carried out one by one. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It shall be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It shall be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked by using standard or special measuring tool templates, the thickness of the bottle body shall be checked by using a thickness gauge, and the inner and outer surfaces of the bottle body shall be polished with special tools.
6.3 Determination of various performance indicators after heat treatment of the bottle body 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and the real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact specimens (3 pieces)
Flat tensile specimens (2 pieces))
Cold bending test (4 pieces)
Figure 3 Test sampling position diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; b) The shape of the tensile specimen preparation is shown in Figure 4;
c) The general requirements for the shape and size of the tensile specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.1 The internal pressure for the design of the steel cylinder shall be the water pressure test pressure. The water pressure test pressure shall be 5/3 times the nominal working pressure. 5.4.1.2 The yield stress guarantee value selected for the design calculation of the cylinder wall thickness shall not be greater than 85% of the tensile strength guarantee value. 5.4.1.3 The actual tensile strength of the material shall be limited. The actual tensile strength of the cylinder body material shall not be greater than 880N/mm2. 5.4.2 The simplified design wall thickness shall be calculated according to formula (1): S
and shall also meet the requirements of formula (2):
5.4.3 End structure
5.4.3.1 There are four types of end structures
a) hemispherical with bottle mouth [see Figure 2a)]; b) hemispherical [see Figure 2b)];
c) dish-shaped [see Figure 2c)];
d) concave [see Figure 2d)].
e./1. 33 - 1. 3P
No/1.33+0.4Ph
（1）
：(2)
GB 17258 -1998
Figure 2 End structure type diagram
5.4.3.2 The dished end structure shall meet the following requirements: r ≥ 0. 075 D.;
H/D. ≥ 0.22; or H/D. ≥ 0.40
S ≥ 1.5 S; Si ≥ s
S2 ≥ 1.5 S; S2 ≥ S
Transition section
5.4.3.3 The nominal dimensions of the concave end shall meet the following requirements. If any of the parameters of the concave end cannot meet the following requirements, it shall be verified by a cyclic fatigue test.
S,=(2.0~2.6)S;
S2=(1.8~2.2)S;
S3 -(2.0~2.8)S;
r = (0.07~0.09)D.
H=(0.13～0.16)D. .
5.4.3.4 There should be a transition section between the ring shell and the cylinder at the concave end, and the connection between the transition section and the cylinder should be smooth. 5.4.3.5 The concave end shall be calculated according to the elastic finite element under the water pressure test pressure P, and shall be checked and adjusted within the tolerance value of the nominal size of the concave end; the stress concentration factor shall not be greater than 1.80. 5.4.3.6 The thickness of the mouth of the cylinder, starting from the thread groove, shall not be less than the design wall thickness of the cylinder, and shall ensure that it does not deform when subjected to the torque of the tightening valve and the additional external force of the riveted collar. 5.4.4 Annex
5.4.4.1 The cylinder valve shall be equipped with a safety pressure relief device, which shall be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, and the allowable deviation is ±5%. The operating temperature of the fusible plug is 100℃±5℃, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve shall meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose shall be marked on the cylinder valve. For example: M (manufacturing factory code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth shall ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《-General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and shall comply with the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the bottle body made by punching and stretching shall meet the specified design value, and the thickness of the end spherical shell and ring shell shall meet the design requirements.
5.5.1.5 The bottle body made by spinning of seamless steel pipe shall be subject to process assessment; there shall be no visible concave holes, wrinkles, bulges and oxide scale on the inner surface of the bottle body end; the defects of the end are allowed to be removed, but the design thickness of the end must be guaranteed; the end is not allowed to be repaired by welding. 5.5.2 Heat treatment
5.5.2.1 The steel cylinder shall be subjected to overall heat treatment, and the heat treatment shall be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature shall not be greater than 930℃, and the tempering temperature shall not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle body in the medium shall not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After the heat treatment of the bottle body, the hardness test and non-destructive testing shall be carried out one by one. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It shall be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It shall be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked by using standard or special measuring tool templates, the thickness of the bottle body shall be checked by using a thickness gauge, and the inner and outer surfaces of the bottle body shall be polished with special tools.
6.3 Determination of various performance indicators after heat treatment of the bottle body 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and the real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact specimens (3 pieces)
Flat tensile specimens (2 pieces))
Cold bending test (4 pieces)
Figure 3 Test sampling position diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; b) The shape of the tensile specimen preparation is shown in Figure 4;
c) The general requirements for the shape and size of the tensile specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile specimen diagram
b.1. The cylinder valve should be equipped with a safety pressure relief device, which should be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, with an allowable deviation of ±5%. The operating temperature of the fusible plug is 100°C ± 5°C, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve should meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose should be marked on the cylinder valve. For example: M (manufacturing plant code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth should ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《- General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as the raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as the raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the cylinder body manufactured by stamping and stretching shall comply with the design specified value, and the thickness of the end spherical shell and annular shell shall comply with the design requirements.
5.5.1.5 Bottles made of seamless steel pipes by spinning should be subject to process assessment; the inner surface of the bottle end should not have visible holes, wrinkles, nodules and oxide scale; defects on the end are allowed to be removed, but the designed thickness of the end must be guaranteed; repair welding is not allowed on the end. 5.5.2 Heat treatment
5.5.2.1 The cylinder should be subjected to overall heat treatment, and the heat treatment should be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature should not be greater than 930℃, and the tempering temperature should not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle in the medium should not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After heat treatment of the bottle, hardness measurement and non-destructive testing should be carried out on each bottle. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It should be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It should be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure should comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body should be checked by standard or special measuring tool templates, the thickness of the bottle body should be checked by thickness gauge, and the inner and outer surfaces of the bottle body should be polished with special tools.
6.3 Determination of various performance indicators of the bottle body after heat treatment 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and a real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact test specimens (3 pieces)
Flat tensile test specimens (2 pieces)
Cold bending test (4 pieces)
Figure 3 Test sampling location diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, elongation; b) The shape of the tensile test specimen is shown in Figure 4;
c) The general requirements for the shape and size of the tensile test specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile test specimen diagram
b.1. The cylinder valve should be equipped with a safety pressure relief device, which should be a bursting disc-fusible plug combination. The nominal bursting pressure of the bursting disc is the water pressure test pressure, with an allowable deviation of ±5%. The operating temperature of the fusible plug is 100°C ± 5°C, and its discharge area must enable the cylinder to pass the fire test specified in Article 7.13.2.
5.4.4.2 The safety pressure relief device on the cylinder valve should meet the requirements of relevant standards. 5.4.4.3 The name or code of the manufacturer, weight, water pressure test pressure and purpose should be marked on the cylinder valve. For example: M (manufacturing plant code), W (weight), Ph (water pressure test pressure), CNG (purpose). 5.4.4.4 The thread matching between the cylinder valve and the bottle mouth should ensure that 2 to 5 pitch threads are left after the cylinder valve is assembled. 5.5 Manufacturing
《- General Provisions
5.5.1.1 The manufacturing of steel cylinders shall comply with the provisions of this standard and the provisions of product drawings and technical documents. 5.5.1.2 The manufacturing method of the cylinder body shall be: using steel as the raw material, it shall be manufactured by stamping and stretching, or using seamless steel pipe as the raw material by spinning. 146
GB 17258—1998
5.5.1.3 The manufacturing of steel cylinders shall be managed in batches, and a batch size of no more than 203 pieces shall be considered as one batch according to the heat treatment sequence. 5.5.1.4 The depth of the concave end of the cylinder body manufactured by stamping and stretching shall comply with the design specified value, and the thickness of the end spherical shell and annular shell shall comply with the design requirements.
5.5.1.5 Bottles made of seamless steel pipes by spinning should be subject to process assessment; the inner surface of the bottle end should not have visible holes, wrinkles, nodules and oxide scale; defects on the end are allowed to be removed, but the designed thickness of the end must be guaranteed; repair welding is not allowed on the end. 5.5.2 Heat treatment
5.5.2.1 The cylinder should be subjected to overall heat treatment, and the heat treatment should be carried out according to the qualified heat treatment process. 5.5.2.2 The quenching temperature should not be greater than 930℃, and the tempering temperature should not be less than 538℃. 5.5.2.3 It is not allowed to quench in water without additives. When water with additives is used as the quenching medium, the cooling rate of the bottle in the medium should not be greater than 80% of the cooling rate in 20℃ water. 5.5.2.4 After heat treatment of the bottle, hardness measurement and non-destructive testing should be carried out on each bottle. 6 Test methods
6.1 Verification of technical indicators of bottle body materials
6.1.1 Chemical composition: It should be carried out according to GB222 and GB223 based on the furnace number of the material. 6.1.2 Macrostructure: It should be carried out according to GB226 based on the furnace number of the material, and the evaluation of macrostructure should comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body should be checked by standard or special measuring tool templates, the thickness of the bottle body should be checked by thickness gauge, and the inner and outer surfaces of the bottle body should be polished with special tools.
6.3 Determination of various performance indicators of the bottle body after heat treatment 6.3.1 Sampling
a) The sampling position is shown in Figure 3;
b) The sample should be cut longitudinally from the middle of the cylinder, and a real flat sample should be used; c) Sampling quantity: no less than 2 tensile test specimens, no less than 3 impact test specimens, and no less than 4 cold bending test specimens. Impact test specimens (3 pieces)
Flat tensile test specimens (2 pieces)
Cold bending test (4 pieces)
Figure 3 Test sampling location diagram
6.3.2 Tensile test
a) The measurement items of the tensile test should include: tensile strength, yield stress, elongation; b) The shape of the tensile test specimen is shown in Figure 4;
c) The general requirements for the shape and size of the tensile test specimen shall be implemented in accordance with GB6397; d) The tensile test method shall be implemented in accordance with GB228. 147
6.3.3 Impact test
GB17258—1998
Figure 4 Tensile test specimen diagram
b.1. 5D.
a) Indenter
Figure 6 Schematic diagram of flattening test
GB 17258-1998
b) Flattening
Figure 6 (end)
6.4 Hardness determination shall be carried out in accordance with GB230 or GB231. 6.5 Metallographic test
a) The metallographic specimen shall be cut from the bottle of the tensile test, and the preparation, size and method of the specimen shall be carried out in accordance with GB/T13298; b) Grain size shall be carried out in accordance with YB/T5148;
c) Depth of decarburized layer shall be carried out in accordance with GB224:
d) The evaluation of banded structure and Widmanstatten structure shall be carried out in accordance with GB/T13299. 6.6 End dissection
6.6.1 End dissection (Fig. 2, b), c), d)) The specimen should be cut from the bottle body for tensile test, and the cross section of the specimen should be on the axis of the bottle body. 6.6.2 The height dimension of the specimen should ensure that the simplified part above the transition section of the bottle end is left. 6.6.3 The inspection method shall be carried out in accordance with GB226.
6.7 Non-destructive testing shall be carried out in accordance with JB4730.
6.8 Check the internal thread of the bottle mouth with visual inspection and standard plug gauge conforming to GB/T8336. 6.9 Burst test
The burst test shall be carried out in accordance with GB15385.
a) There shall be no gas in the pipeline;
b) The pressure increase rate shall not exceed 0.5MPa/s;c) Measure the yield pressure value of the cylinder during the test;d) Measure the total amount of water pressed in from the beginning of the increase to the moment of cylinder explosion;e) Draw a pressure-time or pressure-water inflow curve. 6.10 The water pressure test shall be carried out in accordance with GB/T9251. 6.11 The airtightness test shall be carried out in accordance with GB12137.
6.12 The cyclic fatigue test shall be carried out in accordance with GB9252. The upper limit of the cyclic pressure is the water pressure test pressure. 6.13 The fire test shall be carried out in accordance with Article 7.13.2. 6.14 The explosion impact test shall be carried out in accordance with Article 7.13.3. 7 Inspection rules
7.1 The allowable manufacturing tolerance of the cylinder
7.1.1 The wall thickness deviation of the cylinder shall not exceed +22.5% of the designed wall thickness. 7.1.2 The manufacturing tolerance of the outer diameter of the cylinder shall not exceed ±1% of the design. 7.1.3 The roundness of the cylinder, the difference between the maximum and minimum outer diameters measured on the same section, shall not exceed 2% of the average outer diameter of the section. 7.1.4 The straightness of the cylinder shall not exceed 2% of the length of the bottle body. 7.1.5 The verticality of the bottle body shall not exceed 8% of its length. 7.1.6 The manufacturing tolerance of the height of the bottle body shall not exceed ±15mm. 7.2 Appearance requirements for the inner body of the bottle
GB 17258 -1998
7.2.1 The inner and outer surfaces of the cylinder shall be smooth and round, and there shall be no visible cracks, folds, waves, heavy skin, inclusions and other defects that affect the strength: local smooth depressions caused by the shedding of oxide scale and slight marks after grinding are allowed, but the designed wall thickness of the cylinder must be guaranteed. 7.2.2 The inner surface of the bottom of the bottle body shall not have visible concave holes, wrinkles, bulges and oxide scale; the bottom defects can be removed by machining, but the designed thickness of the bottle bottom must be guaranteed. 7.2.3 The bottle shoulder and the bottom of the bottle must have a smooth transition with the cylinder, and no grooves are allowed on the bottle shoulder. 7.3 Bottle mouth internal thread
7.3.1 The thread profile, size and tolerance shall comply with the provisions of GB8335. 7.3.2 The thread shall not have inverted teeth, flat teeth, double teeth, flat bottom teeth, tooth tips, tooth widths, and obvious ripples on the thread surface. 7.3.3 The effective pitch number from the base of the bottle mouth shall not be less than 8 pitches. 7.3.4 The axial variation of the thread base position is ±1.5mm. 7.4 Mechanical properties test
The mechanical properties of the bottle body after heat treatment shall comply with the provisions of Table 3. Table 3 Mechanical properties of bottle body
Heat treatment state
Test items
Cea/ota
o+N/mms
V-notch test specimen section, mm
ax+J/cm?
7.5 Hardness test
Test overflow, ℃
Average value
Minimum value of single specimen
The hardness value of the bottle body after heat treatment shall meet the requirements of material strength value. 7.6 Cold bending and fan-pressing test
Fire treatment after fire
Guaranteed value of heat treatment by steel cylinder manufacturer
Guaranteed value of heat treatment by steel cylinder manufacturer
7.6.1 The cold bending test and flattening test are qualified if there is no crack. The requirements for the diameter of the bending core and the distance between the pressure heads shall meet the requirements of Table 4. 7.6.2 If the actual tensile strength value exceeds the guaranteed value by 10%, the cold test shall be replaced by the flattening test. Table 4 Requirements for the bending core diameter and pressure head spacing of the cold bending test and the flattening test Actual tensile strength value of the cylinder
Oba,MPa
>580~685
7.7 Metallographic structure inspection sleeve
Bending core diameter
7.7.1 The cylinder body structure should be tempered martensite. Pressure head spacing
Actual tensile strength value of the cylinder
CbaMPa
>685~784
>784~880
Bending core diameter
Pressure head spacing
7.7.2 The depth of the decarburized layer of the bottle body shall not exceed 0.3mm for the outer wall and 0.25mm for the inner wall. 7.7.3 End (Figure 2, b), c), d) After acid etching, there shall be no shrinkage holes, bubbles, unfused, cracks, inclusions or white spots visible to the naked eye on the cross-section specimen, and it shall meet the requirements of 5.4.3. 7.8 Water pressure test
7.8.1 Carry out water pressure test according to the requirements of 5.4.1.1 and 6.10. Within 1 minute of pressure maintenance, the pressure gauge pointer shall not drop back, and the residual volume shall be 150
GB 17258—1998
The deformation rate shall not be greater than 3%; leakage or obvious deformation of the bottle body shall be unqualified. 7.8.2 After the water pressure test, the inside of the cylinder should be dried. 7.9 Airtightness test
7.9.1 The airtightness test pressure is the nominal working pressure. 7.9.2 If the bottle body leaks during the test, it is unqualified. If the bottle mouth leaks due to loose assembly, it is allowed to be repaired and retested. 7.10 Burst test
7.10.1 The actual burst pressure shall not be less than 2.4 times the nominal working pressure. 7.10.2 The pressure of the plastic deformation of the bottle body in the measured burst test shall be greater than or equal to 0.77Ph. 7.10.3 Measured yield The ratio of pressure to bursting pressure should be close to the ratio of the measured yield stress to tensile strength of the bottle material. 7.10.4 There should be no fragments after the bottle explodes, and the rupture must be on the cylinder. The shape and size of the rupture on the bottle should comply with the provisions of Figure 7. 7.10.5 The main rupture of the bottle should be a plastic fracture, that is, there should be an obvious shear lip on the edge of the fracture, and there should be no obvious metal defects on the fracture; the rupture crack should not extend more than 20% of the height of the bottle shoulder. dD/4
Figure 7 Schematic diagram of rupture shape and size
7.11 Non-destructive testing
The bottle should be subjected to non-destructive testing after heat treatment. Non-destructive testing should use magnetic particle detection (Type A high sensitivity test piece) or The ultrasonic testing method shall not have cracks or crack-like defects. According to JB4730, the qualified standard is Level 1. 7.12 Factory inspection
7.12.1 Unit-by-unit inspection
All steel cylinders leaving the factory shall be inspected one by one according to the items specified in Table 5. 7.12.2 Batch inspection
All steel cylinders leaving the factory shall be inspected in batches according to the items specified in Table 5. 7.12.3 Sampling rules
According to the requirements of 5.5.1.3, three steel cylinders are randomly selected for various performance tests. 7.12.4 Re-inspection rules
a) If the test results of the sampled bottle do not meet the specified requirements, the unqualified items shall be re-inspected. Double retest; if the retest results meet the requirements, it is considered qualified; if the retest still fails, the batch of cylinders is allowed to be reheat treated; b) The batch of cylinders that have been repeatedly heat treated should be treated as a new batch and should be re-inspected in batches; c) The cylinder number, reason and conclusion of the repeated heat treatment should be stated in the quality inspection record; d) The number of repeated heat treatments shall not exceed two times. 7.13 Type test
Whenever the cylinder manufacturer encounters one of the following situations, it must conduct a type test. a) Cylinders newly designed by the manufacturer;
b) Cylinders produced by the manufacturer due to changes in the original manufacturing process; c) Cylinders produced by changing the brand of bottle body material; 151
GB 17258-—1998
d) Cylinders produced by changing the bottle body diameter and design wall thickness; e) Cylinders produced by changing the heat treatment method; f) Cylinders produced by changing the minimum kitchen service stress guarantee value exceeding 60N/mm. 7.13.1 Type test items shall be in accordance with the provisions of Table 5. Table 5 Inspection Items
Test Method
Inspection Items
Bottle Wall Thickness
Bottle Manufacturing Tolerance
Bottle Interior and Appearance
Tensile Test
Impact Test
Cold Bending Test
Flattening Test
Hardness Determination
Metallographic Structure
End Anatomy
Non-destructive Testing
Internal Thread of Bottle Mouth
Hydraulic Pressure Test
Air Tightness Test
Explosion Test
Fatigue Cycle Test
Fire Test
Explosion Impact Test Test
7.13.2 Fire test
7.13.2.1 Test device
7.13.2
7.13.3
Factory inspection
Batch inspection
Inspection of each piece
Type test
Judgment basis
7.13.4.2
7.13.2
7.13.3
The cylinder is filled with compressed natural gas to the nominal working pressure, and the cylinder is horizontally erected. The combustion device is 1650mm long, aligned with the cylinder, and placed about 100mm below the cylinder. In order to prevent the flame from directly touching the cylinder valve, connectors and safety devices, a metal guard plate should be used and the metal guard plate should not be in direct contact with the above parts. The combustion device should keep the specified test temperature for not less than 30min. Three thermocouples are fixed on the lower side of the cylinder, with a spacing of no more than 0.75m between them. Metal guards should be used to prevent the flame from directly touching the thermocouples. 7.13.2.2 Test method
After ignition, the flame should surround the entire circumference of the cylinder; within 5 minutes after ignition, all thermocouples should display a temperature of not less than 650°C and continue to maintain a temperature of not less than 650°C.
7.13.2.3 Qualification standard
The cylinder is qualified if it achieves one of the following results: no explosion or safety device release after a 30-minute fire test. However, if the safety device releases within 5 minutes after ignition, the fire test should be continued for at least 5 minutes. 7.13.3 Explosion shock test
7.13.3.1 Test method
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