1 Scope
This standard specifies type and parameter, technical requirements, testing method, test rules, marking, painting, packaging, transport and storage of compressed natural gas steel cylinder for vehicle (hereinafter referred to as steel cylinder).
This standard is applicable to steel cylinders whose design/manufacturing nominal working pressure is 16~20 MPa (the pressured referred in this standard is gauge pressure), nominal volume is 30~120L and working temperature is -50℃~60℃.
Steel cylinders manufactured according to this standard shall contain only natural gas fuel conforming to the relevant standards, whose moisture content per normal cubic meter is not larger than 8 mg, and hepatic gas content per normal cubic meter is not larger than 20 mg after dewatering, desulfurating and light oil removing.
This standard is not applicable to gas steel cylinder used at compressed natural gas refilling station, nor complex material made gas cylinder.
2 Normative References
The provisions of the following standard, through reference into this standard, constitute provisions of this standard. When this standard is published, the editions indicated are valid. All standards are subject to revision, and Parties concerned are encouraged to discuss the possibility of applying the latest edition of the following standards.
GB 222-84 Method of sampling steel for determination of chemical composition and permissible variations for product analysis
GB 223.1-81 Determination of carbon content in iron, steel and alloy
GB 223.2-81 Determination of sulphur content in iron, steel and alloy
GB/T 223.3-88 Methods for chemical analysis of iron, steel and alloy - the diantipyrylmethane phosphomolybdate gravimetric method for the determination of phosphorus content
GB 223.4-88 Methods for chemical analysis of iron, steel and alloy - The volumetric method for determination of manganese content by ammonium nitrate oxidation
GB 223.5-88 Methods for chemical analysis of iron, steel and alloy - Determination of silicon content with dicarboxyl-ferrous sulphate silicon molybdenum blue photometric method
GB/T 223.6-94 Methods for chemical analysis of iron, steel and alloy - The neutralization titrimetric method for the determination of boron content
GB 223.7-81 Determination of iron content in alloy and powder
GB 224-87 Determination of depth of decarburization of steel
GB 226-91 Etch test for macrostructure and defect of steels
GB 228-87 Tensile test for metals
GB/T 229-94 Metallic materials - Charpy notch impact test
GB 230-91 Metallic materials - Rockwell hardness test
GB 231-84 Metallic materials - Brinell hardness test
GB 232-88 Metallic materials - Bend test
GB 1979-80 Diagram of a low magnification texture blemish grading of structural steel
GB 5777-86 Seamless steel pipe and tubing - Methods for ultrsonic testing
GB 6397-86 Metallic materials--Test pieces for tensile testing
GB 7144-86 Color coding for air cylinder
GB 8163-87 Seamless steel tubes for liquid service
GB 8335-1998 Special threads for gas cylinders
GB/T 8336-1998 Special thread gauges for gas cylinders
GB/T 9251-1997 Method for hydraulic test of gas cylinders
GB 9252-88 Method for cycling test of gas cylinders
GB/T 12606-90 Steel tubes and bar - The testing method of magnetic flux leakage
GB 12137-89 Method for pneumatic testing of cylinders
GB/T 13298-91 Metal - Inspection method of microstructure
GB/T 13299-91 Steel - Determination of microstructure
GB 13440-92 Method for flattening test of seamless gas cylinders
GB 13447-92 Steel blank for seamless gas cylinder
GB 15385-94 Method for hydraulic burst test of gas cylinders
JB 4730-94 Nondestructive testing of pressure vessels
YB/T 5148-93 Metal - Methods for estimating the average grain size
3 Terms and Symbols
For the purposes of this standard, the following terms and definitions apply.
3.1 Nominal working pressure
Limited filling pressure of a steel cylinder at base temperature (20℃).
3.2 Yield stress
Yield point or lower yield point selected for condition with obvious yield; or yield strength selected for condition without obvious yield.
3.3 Measured tensile strength
Actually-measured tensile strength obtained according to Article 6.3.2.
3.4 Batch quantity
Limited quantity of steel cylinders continuously heat-treated according to same specification of heat treatment under same design condition, having same nominal diameter, design wall thickness, made of same furnace steel with same manufacturing method.
3.5 Stress concentration factor
Ratio of local maximum stress and cylinder membrane stress of a steel cylinder.
