This standard specifies the requirements of types and parameters, technical requirements, test methods, inspection rules, marking, coating, packing, transport, storage, etc. for hoop-wrapped composite cylinders with steel liner for the on-board storage of compressed natural gas as a fuel for automotive vehicles (hereinafter referred to as "hoop-wrapped cylinders").
This standard is applicable to hoop-wrapped cylinders with 20MPa or 25MPa nominal working pressure for design and manufacture, 30 L~450 L nominal water volume, -40℃~65℃ working temperature and 15-year design service life.
Hoop-wrapped cylinders manufactured according to this standard are only used for filling compressed natural gas meeting GB 18047, as a fuel for automobile vehicles to which the cylinders are to be fixed; the service conditions do not cover additional loads which may arise from external force, etc.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of these documents is applicable. For undated references, the latest edition of the normative document is applicable to this standard.
GB/T 222 "Permissible Tolerances for Chemical Composition of Steel Products"
GB/T 223 (all) "Methods for Chemical Analysis of Iron, Steel and Alloy"
GB/T 224 "Determination of Depth of Decarburization of Steel" (GB/T 224-2008, ISO 3887:2003, MOD)
GB/T 226 "Etch Test for Macrostructure and Defect of Steels"
GB/T 228 "Metallic Materials-Tensile Testing at Ambient Temperature" (GB/T 228-2002, eqv ISO 6892:1998)
GB/T 229 "Metallic Materials-Charpy Pendulum Impact Test Method" (GB/T 229-2007, ISO 148-1:2006, MOD)
GB/T 232 "Metallic Materials-Bend Test" (GB/T 232-1999, eqv ISO 7438:1985)
GB/T 1458 "Test Method for Mechanical Properties of Ring of Filament-winding Reinforced Plastics"
GB/T 2578 "Fabrication Method of Ring Test Specimen for Filament-winding Reinforced Plastics"
GB/T 3362 "Test Methods for Tensile Properties of Carbon Fiber Multifilament"
GB/T 4336 "Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method)"
GB/T 4612 "Plastics-Epoxy Compounds-Determination of Epoxy Equivalent" (GB/T 4612-2008, ISO 300I:1999, IDT)
GB/T 5777 "Seamless Steel Pipe and Tubing Methods for Ultrasonic Testing" (GB/T 5777-2008, ISO 9303: 1989, MOD)
GB/T 7690.1 "Reinforcements-Test Method for Yarns-Part 1: Determination of Linear Density" (GB/T 7690.1-2001, idt ISO 1889:1997)
GB/T 7690.3 "Reinforcements-Test Method for Yarns-Part 3: Determination of Breaking Force and Breaking Elongation for Glass Fiber" (GB/T 7690.3-2001, idt ISO 3341:2000)
GB 8335 "Special Threads for Gas Cylinders"
GB/T 8336 "Special Thread Gauges for Gas Cylinders"
GB/T 9251 "Method for Hydraulic Test of Gas Cylinders"
GB/T 9252 "Method for Cycling Test of Gas Cylinders"
GB/T 12137 "Method for Leakage Test of Gas Cylinders"
GB/T 13005 "Terminology of Gas Cylinders"
GB/T 13298 "Metal-Inspection Method of Microstructure"
GB 15385 "Method for Hydraulic Burst Test of Gas Cylinders"
GB 16918 "Bursting Discs Specification for Gas Cylinder"
GB 18047 "Compressed Natural Gas as Vehicle Fuel"
GB/T 19466.2 "Plastics-Differential Scanning Calorimetry (DSC)-Part 2: Determination of Glass Transition Temperature" (GB/T 19466.2-2004, ISO 11357-2:1999, IDT)
3 Terms, Definitions and Symbols
For the purposes of this standard, the following terms and definitions and ones established in GB/T 13005 apply.
3.1 Terms and Definitions
3.1.1
Nominal working pressure
Limited filling pressure when the hoop-wrapped cylinder is at the reference temperature (20℃).
3.1.2
Hoop-wrap
Hoop-wrap of continuous fiber of impregnating resin in the cylindrical part of the liner, without useful load for fiber in liner's longitudinal direction.
3.1.3
Hoop-wrapped cylinder
Cylinder with an over-wrap having a filament-wound reinforcement in a substantially circumferential pattern over the cylindrical portion of the metal liner.
3.1.4
Liner
Inner-layer seamless shell of hoop-wrapped cylinder, used as sealing for filled gas.
3.1.5
Batch
Liner: one shift of liners, successively produced having the same nominal diameter, wall thickness, design, specified material of construction, process of manufacture, and heat treatment specification for continuous heat treatment.
Hoop-wrapped cylinder: one shift of cylinders, successively produced from qualified liners having the same size, design, specified materials of construction and process of wrapping and solidification.
3.1.6
Auto-frettage
Pressure application procedure used in manufacturing hoop-wrapped cylinders with metal liners, which strains the liner past its yield point sufficient to cause plastic deformation.
Note: This results in the liner having compressive stresses and the fibers having tensile stresses at zero internal pressure.
3.1.7
Auto-frettage pressure
Pressure within the hoop-wrapped cylinder at which the required distribution of stresses between the liner and the over-wrap is established.
3.1.8
Fiber stress ratio
Ratio of fiber stresses under minimum designed burst pressure and under nominal working pressure for hoop-wrapped cylinder.
