GB/T 42536-2023Assembly valve on high pressure hydrogen storage cylinder for vehicles (English PDF)

3.1 Terms and definitions

The terms and definitions, which are defined in GB/T 13005, as well as the following terms and definitions, apply to this document.

3.1.1 Assembly valve on high pressure hydrogen storage cylinder for vehicles

A valve, which is installed on the high-pressure hydrogen storage cylinder for vehicles, and consists of manual shut-off valve, automatic shut-off valve, check valve, temperature-driven safety pressure relief device (TPRD), temperature sensor.

3.2 Symbols

The following symbols apply to this document.

5.1 Materials

5.1.1 Metal materials

5.1.1.1 The main parts and materials of assembly valves (valve body, valve stem, other pressure parts) shall have the original quality certificate, which is provided by the material manufacturer, OR a copy of the quality certificate, which was stamped with the official seal of the material management organization and signed/sealed by the person in charge.

5.1.1.2 The main parts and components of assembly valves shall have good compatibility with hydrogen AND meet the requirements of corresponding material standards.

5.1.2 Non-metallic seal materials

5.1.2.1 The non-metallic seal material shall have the original quality certificate, which is provided by the material manufacturer, OR a copy of the quality certificate, which has the official seal of the material management organization and the signature (seal) of the person in charge. The quality certificate shall include the hardness, tensile strength, elongation at break, etc. of the non-metallic seal material.

5.1.2.2 Non-metallic seals shall be made of materials, which have good compatibility with high-pressure hydrogen. The properties of the seal materials shall meet the requirements in 6.7.

5.2 Design and manufacture

5.2.1 For the assembly valves on high-pressure hydrogen storage cylinders for vehicles, that cannot be disassembled due to structural design of the vehicle body, they shall have a designed service life of not less than 15 years. For the assembly valves on high-pressure hydrogen storage cylinders for other vehicles, they shall have a designed service life of not less than 6 years.

5.2.2 Assembly valves shall have the following functions.

5.2.3 Assembly valve body shall be subject to the finite element stress analysis. Under 2.5 times the nominal working pressure, the stress of each part of the valve body shall not be greater than the guaranteed value of the yield strength of the valve body material.

5.2.4 The gas inlet and outlet thread specifications of assembly valves shall be straight threads, in accordance with GB/T 192, GB/T 196, GB/T 197 or GB/T 20668, OR other threads in accordance with the corresponding standards.

5.2.5 The thread of assembly valve shall be checked for strength; the shear stress safety factor of the thread, at 1.5 times the nominal working pressure, shall not be less than 4.

The calculation method of thread shear stress safety factor shall be carried out, in accordance with Appendix A.

5.2.6 Fusible alloy or glass bubble shall be selected as the safety pressure relief device; the operating temperature is (110 ± 5) °C.

5.2.7 The valve body should be formed by forging and pressing; there shall be no defects such as cracks, wrinkles, inclusions, looseness, shrinkage cavities.

5.2.8 The O-ring shall be tested, according to the provisions of B.3 in Appendix B before selection.

6.1 Metal material test of main components

6.1.1 Mechanical property test

6.1.1.1 Test method

Tensile specimens and test methods for main parts and materials shall be implemented, in accordance with GB/T 228.1. The impact specimens and test methods shall be implemented, in accordance with GB/T 229 (except for aluminum alloy materials).

6.1.1.2 Eligibility indicators

The test results shall meet the requirements of material standards and design.

6.1.2 Chemical composition analysis

6.1.3 Hydrogen compatibility test

6.1.4 Hydrogen embrittlement susceptibility test

6.1.4.1 Test method

The hydrogen embrittlement susceptibility test shall be carried out, in accordance with GB/T 34542.3.

6.1.4.2 Eligibility indicators

The test results shall meet the requirements of material standards and design.

6.2 Visual inspection

6.2.1 Test method

The appearance of the valve body is inspected visually.

6.2.2 Eligibility indicators

Check whether the results meet the following requirements. […]

6.3 Thread inspection

6.3.1 Test method

Use gauges, that comply with GB/T 3934 or corresponding standards, to make inspection.

6.3.2 Eligibility indicators

The inspection results shall meet the following requirements. […]

6.4 Air tightness test

6.4.1 Test method

In accordance with the provisions of Appendix C, the air tightness test shall be carried out, under normal temperature conditions at (2 ± 0.5) MPa and a pressure not lower than 1.25p, respectively. The test medium shall be pure helium. According to the structure of the assembly valve, the internal leakage and external leakage tests are carried out, respectively.

6.4.2 Eligibility indicators

Helium leak rate shall not exceed 7.5 mL/h.

6.5 TPRD test

6.5.1 Hydrogen cycle test

6.5.2 Accelerated life test

6.5.2.1 Test method

The test procedure is as follows. […]

6.5.3 Temperature cycle test

6.5.3.1 Test method

The test steps are as follows. […]

6.5.3.2 Eligibility indicators

After the temperature cycle test, the TPRD shall comply with the provisions of 6.5.9 leak test, 6.5.10 action test, 6.5.11 flow test. The temperature of the leak test shall not be higher than -40 °C.

6.5.4 Salt spray corrosion resistance test

6.5.4.1 Test method

The test requirements are as follows. […]

6.5.5 Condensation corrosion resistance test

6.5.5.1 Test method

The test procedure is as follows. […]

7.1 Material inspection

7.1.1 The metal raw materials shall be subject to mechanical property retest based on batch, AND chemical composition retest based on furnace number, which shall comply with the provisions of 6.1.1 and 6.1.2.

7.1.2 O-rings shall be visually inspected one by one; they shall meet the requirements of B.3.1. Other non-metallic seals shall be visually inspected one by one; the appearance shall be intact and free of defects.

7.1.3 O-rings shall be subject to size inspection and oxygen aging resistance test based on batch size; it shall meet the requirements of B.3.2 and 6.7.1.

7.2 Exit-factory inspection

7.2.1 Inspection one by one

Assembly valves shall be inspected one by one, before leaving the factory. The inspection items shall be in accordance with the provisions in Table 2. During the inspection process, if there is an unqualified item, the valve is unqualified.

7.3 Type test

7.3.1 If the assembly valve has one of the following conditions, the type test shall be carried out by the inspection agency, that has obtained the corresponding valve type test qualification.

7.3.2 Assembly valves for type test shall be selected, from the products that have passed the exit-factory inspection. See Table 3 for the test items. See Figure 3 and Figure 4, for the test sequence and number of test pieces for the type test. All items of the type test shall meet the requirements of this document. If there is any test result of a valve, that does not meet the requirements of this document, it will be determined that the type test of the valve fails. If it is caused by design reasons, the manufacturer shall change the design; carry out trial production according to the changed design; re-take samples for type tests of all items. If it is caused by improper process or manufacturing control, the manufacturer shall submit a written descriptions on solving the problem, to the type test agency.

8.1 Sign

The assembly valve shall have the following permanent and clear signs.

8.2 Packaging, transportation, storage

8.2.1 The moisture remaining in the valve shall be removed before packaging. During packaging, the valve shall be kept clean, free from oil and corrosion. The air inlet and outlet threads shall not be damaged.

8.2.2 The product qualification certificate and instruction manual should be attached inside the packing box.

9.1 Product certificate

The exit-factory product certificate shall at least include the following contents. […]

9.2 Batch inspection quality certificate

9.2.1 Products, which are exit-factory in batches, shall have a batch inspection quality certificate.

9.2.2 The content of the product batch inspection quality certificate shall include the exit-factory inspection items, product batch number, product quantity, which are specified in this document.

9.2.3 The issuance of the product batch inspection quality certificate shall be signed (sealed) by the product quality inspection responsible person or quality assurance engineer, which is authorized by the top management of the manufacturer. […]