Some standard content:
National Standard of the People's Republic of China
Seamless Steel Gas Cylinders
Seamless Steel Gas CylindersSubject Content and Scope of Application
GB 5099---94
Replaces GI5099-85
This standard specifies the types and parameters, technical requirements, test methods, inspection rules, marking, coating, packaging, transportation and storage of seamless steel gas cylinders (hereinafter referred to as cylinders).
This standard applies to the design and manufacture of refillable mobile cylinders with a nominal working pressure of 8~30MPa and a nominal volume of 0.480L for containing permanent gas or high-pressure liquefied gas. The ambient temperature of the cylinders in general areas is -20~60℃, and the ambient temperature of the cylinders in cold areas is ~40~60℃.
This standard does not apply to cylinders containing dissolved gas, adsorbed gas, cylinders for fire extinguishing, and bottle-type pressure vessels attached to transportation vehicles and machinery and equipment.
2 Reference standards
GB222 Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products GB223.1~223.7 Chemical analysis methods for steel and alloys GB224
Method for measuring the depth of decarburized layer in steel
Acid etching test method for macrostructure and defects in steel Metal tensile test method
Metal Rockwell hardness test method
Metal Brinell hardness test method
Metal bending test method
GB 1979
GB 2106
GB3077
GB 4159
GB 5777
GB6394
GB7144
GB 8163
GB8335
GB 9251
GB9252
Structural steel macrostructure defect rating chart
Metal Charpy (V-notch) impact test method Technical conditions for alloy structural steel
Metal low-temperature Charpy impact test method
Ultrasonic flaw detection method for seamless steel pipe
Method for determining average grain size of metal
Color marking of gas cylinders
Seamless steel pipes for conveying fluids
Special thread for gas cylinders
Hydraulic pressure test method for gas cylinders
Fatigue test method for gas cylinders
GB12137
Gas cylinder airtightness test method
GB/T 13005
GB/T 13298
Terms of gas cylinders
Methods for testing metal microstructures
Approved by the State Administration of Technical Supervision on December 26, 1994 and implemented on August 1, 1995
GB/T13299 Method for evaluating steel microstructures GB13440 Tenderness test method for seamless gas cylinders
GB13447 Steel for seamless gas cylinders
GB15385 Water pressure bursting test method for gas cylinders
3 Technical terms and symbols
GB.5099-94
3.1 Permanent gas: gas with a critical temperature less than -10°C; high-pressure liquefied gas: critical temperature greater than or equal to -10°C and less than or equal to 70°C. 3.2 Nominal operating pressure: For steel cylinders containing permanent gases, it refers to the limited filling pressure of the gas contained at the reference temperature (generally 20°C); for steel cylinders containing high-pressure liquefied gases, it refers to the upper limit of the gas pressure in the cylinder at a temperature of 60°C. 3.3 Permissible pressure: The maximum pressure allowed to be borne by the steel cylinder during filling, use, storage and transportation. 3.4 Yield stress: For the tensile test of the material specimen, if there is an obvious yield phenomenon, the yield point or lower yield point shall be taken; if there is no obvious yield phenomenon, the yield strength shall be taken.
3.5 Batch: It 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, the same manufacturing method, and are continuously heat treated according to the same heat treatment specifications. 3.6 Design stress coefficient: The ratio of the design value of the yield stress of the bottle material to the equivalent stress of the cylinder under the water pressure test pressure. 3.7 Filling coefficient: The maximum gas weight allowed to be filled per unit water volume of the steel cylinder specified in the standard. 3.8 Stress concentration factor: the ratio of the membrane stress of the bottle body to the local maximum stress. 3.9 Symbols:
CM chromium-molybdenum steel or other alloy steel for quenching and tempering; outer diameter of cylinder barrel, mm;
bend core diameter of cold bending test, mm;
F design stress factor (see 5.2.4);
Mn carbon-manganese steel for normalizing or tempering after normalizing; MnH carbon-manganese steel for quenching and tempering;
calculated bursting pressure, MPa;
actual bursting pressure, MPa;
hydraulic pressure test pressure, MPa;
yield pressure during bursting test, MPa; P
designed wall thickness of cylinder barrel, mm;
actual minimum wall thickness of cylinder barrel, mm; ||tt ||Average wall thickness of cylinder body, mm;
Spacing of pressure heads in flattening test, mm;
Original thickness of curved flat specimen, mm;
Original width of specimen, mm;
d, d2 circumferential tear length of rupture, mm; Original mark of specimen, mm;
Impact toughness value, J/cm\;
Elongation, %;
Guaranteed yield stress value of cylinder body material after heat treatment, N/mm\;Gea
Measured yield stress value, N/mm2;
Guaranteed tensile strength value of cylinder body material after heat treatment, N/mm;a
Measured tensile strength value, N/mm2.
Types and parameters of cylinder
509994
4.1 Cylinder body - Generally, it shall conform to the type shown in Figure 1. The typical structure and main accessories of steel cylinders with concave bottom and convex bottom with base are shown in Figure 2.
4.2 The nominal volume and outer diameter of steel cylinders shall generally comply with the provisions of Table 1. 4.3 The nominal working pressure and filling coefficient of commonly used bottled gases are shown in Table 2. Figure 1 Steel cylinder body type
GB5099---94
Figure 2 Typical structural categories of steel cylinders with concave bottom and convex bottom with base
Small volume
Medium volume
Nominal volume
GB5099—94
Table 1 Nominal volume and outer diameter of steel cylinders
Allowance deviation of water volume
Outer diameter D.
89,108
108.120,140
120,140
140,152
152,159
152,159,178,180
203,219
219,229,232
245,267,273
Allowable deviation
Gas category
Permanent gas
High-pressure liquefied gas
5 Technical requirements
GB5099—94
Table 2 Nominal working pressure and filling coefficient of common bottled gases Gas name
Oxygen, nitrogen, hydrogen or others
Carbon dioxide
Nitrous oxide
Sulfur hexafluoride
Hydrogen chloride
Trifluoroethane
Trifluoromethane
Hexafluoroethane
Vinylidene fluoride
Vinyl fluoride
Bromotrifluoromethane
5.1 General provisions for bottle materials
Chemical formula
O2, N2, H2
C2H.(CH:CHs)||tt| |C,H,(CH2-CH2)
C,F,(CF:CF3)
C,H2F2
(CH2=CF2)
(CH2=CHF)
Nominal working pressure,
Filling factor
5.1.1 Non-aging killed steel smelted in basic open-hearth furnace, electric furnace or oxygen-blown basic converter must be used. 5.1.2 The type of steel used to manufacture steel cylinders must be identified and approved by relevant national or international departments, and high-quality manganese steel, chrome-molybdenum steel or other alloy steels should be selected. 5.1.3 The materials used to manufacture steel cylinders must comply with the provisions of the corresponding national standards or industry standards and have a quality certificate. The steel cylinder manufacturer should conduct various verification analyses according to the furnace number. 5.1.4 The body material of the steel cylinder should have good impact resistance. 516
GB5099-94
5.1.5 The chemical composition of the cylinder body material is limited to Table 3. The allowable deviation of the chemical composition shall comply with the provisions of Table 2 in GB222. Table 3 Chemical composition of the cylinder body material
Composition, %
Heat treatment method
1.40~1.75
Carbon manganese steel
Normalizing or tempering after normalizing
Chrome aluminum steel or other alloy steel
0. 26~~0. 34
0.40~0.70
0.17~0.37
0.80~1.10
0. 15~0.25
Tempering after quenching
0.32~~0.40
0. 40~~0. 70
0.17~0.37
0.80~1.10
0. 15~0. 25
5.1.6 If the normalizing method is used to manufacture small-volume steel cylinders, carbon steel materials can be used; if the quenching and tempering method is used, alloy steel materials can be used.
5.1.7 Initial rolling or steel bars
5.1.7.1 The shape, size and allowable deviation of steel bars shall comply with the relevant provisions of GB13447. 5.1.7.2
Low-magnification structure
White spots, residual shrinkage cavities, stratification, bubbles, foreign matter and inclusions are not allowed; the central porosity shall not exceed 1.5 levels, and the segregation shall not exceed 2.5 levels. 5.1.8 Seamless steel pipe
5.1.8.1 The appearance and internal and external surface quality of the steel pipe shall not be lower than the provisions of GB8163. 5.1.8.2 The wall thickness deviation of the steel pipe shall not exceed ±15% of the nominal wall thickness. 5.1.8.3 If the steel pipe has been inspected by the steel mill, the manufacturer can randomly check 10% of the same batch of steel pipes; if the steel mill has not inspected each pipe, the gas cylinder manufacturer should inspect each pipe, and the inspection qualification level should comply with the provisions of GB8163. 5.1.9 For the identified steel type, the cylinder manufacturer should manufacture no less than 20,000 cylinders for use, and the steel type recognized by the state can be submitted to the standard only after the quality meets all requirements.
5.2 General design provisions
5.2.1 The wall thickness design of the pressure-bearing part shall take the guaranteed value of 6 after heat treatment of the material. For normalized steel cylinders, the guaranteed value of yield stress c after heat treatment shall not be greater than 520N/mm2.
5.2.2 The design calculation of the cylinder wall thickness shall be based on the water pressure test pressure P. The water pressure test pressure of the cylinder is 1.5 times the nominal working pressure, and the allowable pressure of the permanent gas cylinder shall not exceed 0.8 times the water pressure test pressure. 5.2.3 The yield stress selected for design calculation shall not be greater than 75% of the minimum tensile strength for normalizing or tempering after normalizing; and shall not be greater than 85% of the minimum tensile strength for tempering after quenching. 5.2.4 Limitation of design stress
5.2.4.1 The actual maximum tensile strength of the material shall be controlled. The maximum tensile strength of the heat treatment after quenching and tempering shall not be greater than 1000N/mm2; the maximum tensile strength of small-volume bottles shall not be greater than 1100N/mm2. For media with stress corrosion tendency, the tensile strength shall not be greater than 880 N/mm2.
5.2.4.2 Selection of the design stress coefficient F value For the design of steel cylinders treated by normalizing or tempering after normalizing, the F value shall be 0.82; a.
b. For the design of steel cylinders subjected to tempering heat treatment after quenching, the F value is 0.77. 5.2.5 Minimum wall thickness formula for cylinder design
2Fa+Ph
It should also meet the requirements of formula (2) and should not be less than 1.5mm. s
5.2.6 Bottom structure
5.2.6.1 There are three types of convex bottoms:
hemispherical;
dish (see Figure 3a, b, c);
H-shaped (see Figure 3d).
Figure 3 Convex bottom structure diagram
5.2.6.2 The structure of dish bottom and H-shaped bottom should meet the following requirements: r≥0. 075 D. ;
H/D. ≥0.22; or H/D. ≥0.40
Si≥1.5 S;
S,≥1. 5 S;
（2）
The connection between the convex bottom and the cylinder shall be smooth and its thickness shall not be less than the minimum wall thickness of the cylinder design. 5.2.6.3 The nominal dimensions of the concave bottom shall meet the following requirements (see Figure 4). If the parameters of the concave bottom bottle made of tube cannot meet the following requirements, it can be verified by pressurized fatigue test. St =(2. 0~ 2. 6)S;
S,-(1.8~2. 2)S;
S:=(2. 0~2.8)S;
r=(0. 07~0. 09)D. ;bzxz.net
H -- (0. 13~0. 16)D..
GB5099--94
Figure 4 Concave bottom structure diagram
Transition section
5.2.6.4 There should be a transition section between the ring shell and the cylinder of the concave bottom, and the connection between the transition section and the cylinder should be smooth. 5.2.6.5 The convex bottom or concave bottom should be calculated according to the elastic finite element under the water pressure test pressure P, and the calibration and adjustment should be carried out within the tolerance value range of the nominal size of the convex or concave bottom; the stress concentration factor shall not be greater than 1.80, and the local maximum stress value shall not be greater than the strength value of the material. 5.2.7 The design of convex bottom and concave bottom cylinders should be subjected to cyclic pressure fatigue test. The upper limit of the cyclic pressure is 80,000 cycles under the nominal working pressure conditions, or 12,000 cycles under the test pressure conditions. If it is not destroyed, it is qualified; if the test fails, the design should not be adopted.
5.2.8 The thickness of the mouth of the steel cylinder, measured from the thread groove, shall not be less than the designed wall thickness of the cylinder body, to ensure that it will not deform when subjected to the torque moment of the tight valve and the additional external force of the riveted collar.
5.3 Manufacturing
5.3.1 In addition to complying with the provisions of this standard, the manufacturing of steel cylinders shall also comply with the provisions of product drawings and technical conditions. 5.3.2 The manufacturing method of the steel cylinder body is generally: using steel or steel plate as raw materials, it is manufactured by punching, drawing, stamping and stretching; using seamless steel pipe as raw material, it is manufactured by bottoming and closing.
5.3.3 The chemical composition and macrostructure of the cylinder body materials entering the factory shall be verified, and the analysis results shall meet the requirements of Article 5.1. 5.3.4 Permissible manufacturing tolerance of the cylinder body
5.3.4.1 The roundness of the cylinder body, 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. 5.3.4.2 The straightness of the cylinder shall not exceed 2% of the length of the bottle. 5.3.4.3 The verticality of the bottle shall not exceed 8% of its length. 5.3.5. Requirements for the inner and outer surfaces of the cylinder
5.3.5.1 The inner and outer surfaces of the cylinder shall be smooth and round, and shall not have 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 traces after grinding are allowed to exist, but the designed wall thickness of the cylinder must be guaranteed. 5.3.5.2 The concave bottom depth of the bottle made by extrusion and stretching shall meet the design specified value, and the thickness of the bottom spherical shell and ring shell shall meet the design requirements.
5.3.5.3 The bottle made of seamless steel pipe by shrinking the bottom shall be subject to process evaluation; there shall be no visible concave holes, wrinkles, bulges and oxide scale on the inner surface of the bottom of the bottle; the bottom and defects can be removed, but the designed thickness of the bottle bottom must be guaranteed; the bottle bottom is not allowed to be repaired by welding. 519
GB5099—94
5.3.5.4 The bottle shoulder and the cylinder must have a smooth transition, and no grooves are allowed on the bottle shoulder. 5.3.6 The base material of the medium-volume convex bottom steel cylinder should be compatible with the bottle body, and should be firmly assembled by the heat sleeve method. Welding assembly is strictly prohibited. The distance between the base ground plane and the bottom of the bottle should be no less than 10mm. 5.3.7 Heat treatment
5.3.7.1 In addition to complying with the standard provisions, the steel cylinder manufacturer should formulate corresponding heat treatment specifications. 5.3.7.2 The bottle body should be batched according to the heat treatment sequence. The medium-volume bottle should not exceed 502 pieces as a batch; the small-volume bottle should not exceed 202 pieces as a batch.
When using the quenching process, oil or water with additives can be used as the quenching medium. When adding additives to water as a quenching medium, the cooling rate of the bottle body in the medium shall not be greater than 80% of the cooling rate in 20°C water; and the corresponding heat treatment process assessment shall be completed. 5.3.7.4 For bottles treated by tempering after quenching, the hardness value shall meet the material strength value requirements. 5.3.7.5 According to the requirements of 5.2.1.5.2.2, the mechanical properties of the bottle body after heat treatment shall comply with the provisions of Table 4. Table 4 Heat treatment and mechanical properties of steel cylinder body Heat treatment state
Test items
Gn/oua
01,N/mm2
V-notch specimen section
Test temperature, ℃
Average value
Minimum value of a single specimen
5.3.7.6 Cold bending and flattening
Normalizing or
After normalizing
Quenching and tempering
Tempering
Heat treatment guaranteed value of steel cylinder manufacturer
Heat treatment guaranteed value of steel cylinder manufacturer
Cold bending test and flattening test are qualified if there is no crack, and the requirements for the diameter of the bending core and the distance between the pressure heads shall comply with the provisions of Table 5. 5×10
For the bottle body treated by normalizing or tempering after normalizing, if the actual measured value of the tensile strength exceeds the guaranteed value by 15%, for the bottle body treated by quenching and tempering b.
, if the actual measured value of the tensile strength exceeds the guaranteed value by 10%, the cold bending test shall be replaced by the flattening test. Table 5 Requirements for the bending core diameter and pressure head spacing of cold bending flattening test Actual tensile strength value of steel cylinder
ia, MPa
>580~685
>685~784
>784～880
>880~～950
950～1100
5.3.7.7 Metallographic structure
Bending core diameter
Pressure head spacing
GB 5099--94
The matrix structure of the bottle body shall comply with the corresponding heat treatment specifications; a.
b. For the bottle body treated by normalizing or tempering after normalizing, the grain size shall not be less than grade 6 (100 times), the banded structure shall not be greater than grade 3, and the Widmanstatten structure shall not be greater than grade -;
c. For the bottle body treated by tempering after quenching, its structure should be tempered martensite; d. 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. 5.3.7.8 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 Article 5.2.6.
5.3.7.9 For the bottle body treated by tempering after quenching, non-destructive testing shall be carried out one by one, and there shall be no cracks or crack defects. 5.3.8 Internal thread of bottle mouth
5.3.8.1 The tooth type, size and tolerance of the thread shall comply with the provisions of GB8355. It is not allowed to have reverse teeth, flat teeth, double teeth, flat bottom teeth, tooth tips, tooth width and obvious runout ripples on the thread surface. 5.3.8.2 The effective pitch number from the base of the bottle mouth shall not be less than 8 pitches for medium-volume bottles and not less than 7 pitches for small-volume bottles. 5.3.8.3 The axial variation of the base position of the bottle thread is +1.5mm. 5.3.8.4 The bottle mouth thread of special-purpose steel cylinders can be designed and manufactured according to special requirements. 5.3.9 Explosion
5.3.9.1 The actual explosion pressure shall not be less than the calculated value of formula (3): 20b·S
D. -s× C
Use normalizing or tempering after normalizing
Use tempering after quenching
HP≥1.7 Ph
5.3.9.2 The pressure of the plastic deformation of the bottle during the actual explosion process shall not be less than Ph/F, that is, P,≥Ph×F. 5.3.9.3 The ratio of the measured yield pressure to the bursting pressure shall be close to the ratio of the measured yield stress to the tensile strength of the bottle body material. 5.3.9.4 The breach without fragments after the bottle body bursts must be on the cylinder. The shape and size of the breach on the bottle body shall comply with the provisions of Figure 5. Breach shape of various heat treatment states
Break shape of normalizing or tempering after normalizing d,D/2
Break shape of tempering after quenching
Figure 5 Schematic diagram of breach shape and size
5.3.9.5 The main fracture of the bottle body 11 should be plastic fracture, that is, the edge of the fracture should have obvious shear lips; there should be no obvious metal defects on the fracture; the crack of the fracture 521
shall not extend more than 20% of the height of the bottle shoulder. GB 5099—94
5.3.10 Carry out water pressure test according to the requirements of 5.2.3. Within 1 minute of pressure maintenance, the pressure gauge pointer shall not drop back, and the volume residual deformation rate of the medium volume bottle shall not be greater than 3%; the bottle shall be scrapped if it leaks or is obviously deformed. 5.3.11 The airtightness test pressure is the nominal working pressure. If the bottle leaks, it shall be scrapped. Leakage caused by assembly is allowed to be repaired and retested.
5.3.12 According to user needs, the inner surface of the bottle shall be dried and sealed after the water pressure or airtightness test. 5.3.13 Annex
5.3.13.1 The neck ring can be made of steel plate, malleable cast iron, ductile iron or cast steel. The assembly of the neck ring and the bottle body shall not be skewed, loose or have burrs, and the bottle mouth thread shall not be damaged due to improper assembly. Welding assembly is strictly prohibited. 5.3.13.2 Different bottle valves are used according to the filling gas or use requirements. After the bottle valve is assembled with the bottle body, 2 to 5 pitches of spare threads should be left.
5.3.13.3 Bottle caps are divided into fixed and removable types. They can be made of steel plates, steel pipes, cast steel, malleable cast iron and ductile iron; if the user has no special requirements, they should be shipped with fixed bottle caps. 5.3.13.4 For accessories connected by threads, the thread profile, size and tolerance should comply with the provisions of GB8335. 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: The furnace number of the material shall be carried out according to GB226, 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 of the bottle body after heat treatment 6.3.1 Sampling
The sampling position is shown in Figure 6;
The sample shall be cut longitudinally from the middle of the cylinder body, and a real flat sample shall be used; Sampling quantity: tensile test specimens shall be no less than 2; impact test specimens shall be no less than 3, and cold bending test specimens shall be no less than 4. Impact test specimens (3 pieces)
Fan tensile test specimens (2 missing)
Bending test (4 pieces)
6.3.2 Tensile test and impact test
6.3.2.1 Tensile test
The measurement items of the tensile test shall include: tensile strength, yield stress, elongation; a.
b. The shape of the tensile test specimen is shown in Figure 7;1 The actual bursting pressure shall not be less than the calculated value of formula (3): 20b·S
D. -s× C
Use normalizing or tempering after normalizing
Use tempering after quenching
HP≥1.7 Ph
5.3.9.2 The pressure of the plastic deformation of the bottle body during the measured bursting process shall not be less than Ph/F, that is, P, ≥Ph×F. 5.3.9.3 The ratio of the measured yield pressure to the bursting pressure shall be close to the ratio of the measured yield stress to the tensile strength of the bottle body material. 5.3.9.4 The breakthrough point without fragments after the bottle body is exploded must be on the cylinder. The shape and size of the door on the bottle body shall comply with the provisions of Figure 5. Crack shape in various heat treatment states
Crack shape of normalizing or tempering after normalizing d, D/2
Crack shape of tempering after quenching
Figure 5 Schematic diagram of crack shape and size
5.3.9.5 The main fracture of the bottle body 11 should be plastic fracture, that is, there should be obvious shear lip on the edge of the fracture; there should be no obvious metal defects on the fracture; the crack of the fracture 521
should not extend more than 20% of the height of the bottle shoulder. GB 5099-94
5.3.10 Carry out water pressure test according to the requirements of 5.2.3. Within 1min of pressure maintenance, the pressure gauge pointer shall not drop back, and the volume residual deformation rate of the medium volume bottle shall not be greater than 3%; the bottle will be scrapped if it leaks or is obviously deformed. 5.3.11 The airtightness test pressure is the nominal working pressure. If the bottle leaks, it should be scrapped. Leakage caused by assembly is allowed to be repaired and retested.
5.3.12 According to user needs, after the water pressure or air tightness test, the inner surface of the bottle body should be dried and sealed. 5.3.13 Accessories
5.3.13.1 The neck ring can be made of steel plate, malleable cast iron, ductile iron or cast steel. The assembly of the neck ring and the bottle body shall not be skewed, loose or have burrs, and the bottle mouth thread shall not be damaged due to improper assembly. Welding assembly is strictly prohibited. 5.3.13.2 Different bottle valves are used according to the filling gas or use requirements. After the bottle valve is assembled with the bottle body, 2 to 5 pitches of spare threads should be left.
5.3.13.3 The bottle cap type is divided into fixed or removable. It can be made of steel plate, steel pipe, cast steel, malleable cast iron and ductile iron; if the user has no special requirements, it should be shipped with a fixed bottle cap. 5.3.13.4 For accessories connected by thread, the thread type, size and tolerance shall comply with the provisions of GB8335. 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. The evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked with standard or special measuring tool templates, the thickness of the bottle body shall be checked with 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
The sampling position is shown in Figure 6;
The sample should be cut longitudinally from the middle of the cylinder, and a real flat sample should be used; Sampling quantity: tensile test specimens should be no less than 2; impact test specimens should be no less than 3, and cold bending test specimens should be no less than 4. Impact specimens (3 pieces)
Fan tensile specimens (2 missing)
Bending test (4 pieces)
6.3.2 Tensile test and impact test
6.3.2.1 Tensile test
The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; a.
b. The shape of the tensile specimen preparation is shown in Figure 7;1 The actual bursting pressure shall not be less than the calculated value of formula (3): 20b·S
D. -s× C
Use normalizing or tempering after normalizing
Use tempering after quenching
HP≥1.7 Ph
5.3.9.2 The pressure of the plastic deformation of the bottle body during the measured bursting process shall not be less than Ph/F, that is, P, ≥Ph×F. 5.3.9.3 The ratio of the measured yield pressure to the bursting pressure shall be close to the ratio of the measured yield stress to the tensile strength of the bottle body material. 5.3.9.4 The breakthrough point without fragments after the bottle body is exploded must be on the cylinder. The shape and size of the door on the bottle body shall comply with the provisions of Figure 5. Crack shape in various heat treatment states
Crack shape of normalizing or tempering after normalizing d, D/2
Crack shape of tempering after quenching
Figure 5 Schematic diagram of crack shape and size
5.3.9.5 The main fracture of the bottle body 11 should be plastic fracture, that is, there should be obvious shear lip on the edge of the fracture; there should be no obvious metal defects on the fracture; the crack of the fracture 521
should not extend more than 20% of the height of the bottle shoulder. GB 5099-94
5.3.10 Carry out water pressure test according to the requirements of 5.2.3. Within 1min of pressure maintenance, the pressure gauge pointer shall not drop back, and the volume residual deformation rate of the medium volume bottle shall not be greater than 3%; the bottle will be scrapped if it leaks or is obviously deformed. 5.3.11 The airtightness test pressure is the nominal working pressure. If the bottle leaks, it should be scrapped. Leakage caused by assembly is allowed to be repaired and retested.
5.3.12 According to user needs, after the water pressure or air tightness test, the inner surface of the bottle body should be dried and sealed. 5.3.13 Accessories
5.3.13.1 The neck ring can be made of steel plate, malleable cast iron, ductile iron or cast steel. The assembly of the neck ring and the bottle body shall not be skewed, loose or have burrs, and the bottle mouth thread shall not be damaged due to improper assembly. Welding assembly is strictly prohibited. 5.3.13.2 Different bottle valves are used according to the filling gas or use requirements. After the bottle valve is assembled with the bottle body, 2 to 5 pitches of spare threads should be left.
5.3.13.3 The bottle cap type is divided into fixed or removable. It can be made of steel plate, steel pipe, cast steel, malleable cast iron and ductile iron; if the user has no special requirements, it should be shipped with a fixed bottle cap. 5.3.13.4 For accessories connected by thread, the thread type, size and tolerance shall comply with the provisions of GB8335. 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. The evaluation of macrostructure shall comply with the provisions of GB1979. 6.2 The manufacturing tolerance of the bottle body shall be checked with standard or special measuring tool templates, the thickness of the bottle body shall be checked with 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
The sampling position is shown in Figure 6;
The sample should be cut longitudinally from the middle of the cylinder, and a real flat sample should be used; Sampling quantity: tensile test specimens should be no less than 2; impact test specimens should be no less than 3, and cold bending test specimens should be no less than 4. Impact specimens (3 pieces)
Fan tensile specimens (2 missing)
Bending test (4 pieces)
6.3.2 Tensile test and impact test
6.3.2.1 Tensile test
The measurement items of the tensile test should include: tensile strength, yield stress, and elongation; a.
b. The shape of the tensile specimen preparation is shown in Figure 7;
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