ISO 9809-4:2014 pdf download – Gas cylinders – – Refillable seamless steel gas cylinders一Design, construction and testing一 Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa
ISO 9809-4:2014 pdf download – Gas cylinders – – Refillable seamless steel gas cylinders一Design, construction and testing一 Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa.
10 Batch tests
10.1 General requirements
10.1.1 All tests for checking the quality of the gas cylinder shall be carried out at the completion of the cylinder manufacture, i.e. at any stage after the heat treatment.
For the purpose of the batch testing, the manufacturer shall provide the inspector with
— the type approval certificate,
— the certificates stating the cast analysis of the steel supplied For the construction of the cylinders.
— an evidence that appropriate heat treatment has been performed.
— the certificates showing the ultrasonic examination results.
— a list of the cylinders, stating the serial numbers and stamp markings, as required, and
— a confirmation that threads have been checked in accordance with gauging requirements, the gauges to be used shall be specified (e.g. ISO 11191).
10.1.2 DurIng the batch testing, the inspector shall undertake the following.
— Ascertain that the type approval certificate has been obtained and that the cylinders conform to IL
— Check whether the requirements given in Cliwses0, 7, and U have been met and, in particular, check by an external and internal visual examination of the cylinders whether their construction is satisfactory. The inspector shall verify that the requirements of ZZ Z and Ui to fl.9 have been fulfilled by the manufacturer. The visual examination shall cover at least 10 % of the cylinders submitted. However. If an unacceptable Imperfection Is found (for examples, see Annex A), 100 % of cylinders shall be visually inspected.
— Select the necessary cylinders per batch for destructive testing and carry out the tests specified in 10.1.2 a) (hydraulic burst tests) and 10.1.2 b) (mechanical testing). Where alternative tests are permitted, the purchaser and manufacturer shall agree which tests are to he carried out. Where cold working or cryoforming causes Inhomogenelty of mechanical properties within the cylinder, sufficient sets of test pieces shall be taken in accordance with Figure 4 to prove the design.
— Check whether the Information supplied by the manufacturer referred to in 10.L1 Is correct; random checks shall be carried out.
— Assess the results of the hardness testing specified In 11.3.
The following tests shall be carried out on each batch of cylinders:
a) on one cylinder, one hydraulic burst test (see 10.);
b) on a further cylinder:
— one tensile test In the longitudinal direction (see 1fl2);
— either two bend tests (see 103.1) in a circumferential direction, one flattening test (see 1U32). or one ring flattening test (see 10.13);
— when necessary and when the thickness of the cylinder permits the machining of a test piece at least 3 mm thick, three Impact tests in the transverse or longitudinal direction as required In
— for cylinders made from austenltlc and duplex steels, an Intergranular corrosion test In accordance with 10.6
10.5.3.3 The cylinder shall remain in one piece and shall not fragment.
10.5.3.4 The main fracture shall be in the cylindrical portion and shall not be brittle. i.e. the fracture edges shall be inclined with respect to the wall. The tear shall not reveal a significant defect In the metal and in no case shall reach the neck. For concave bases, the tear shall not run further than the cylindrical body at the base end and, for convex bases, the tear shall not reach the centre of the base.
10.5.3.5 For cylinders with a wall thickness less than 7,5 mm, the fracture shall be acceptable only if it conforms to one of the following descripons.
a) For quenched and tempered cylinders:
— longitudinal, without branching see EigunilO);
— longitudinal, with a side branching at each end which in no case extends beyond the longitudinal plane normal to the fracture plane (ci D/4; see F1gur4J..1);
b) For cryolormed or solution-annealed cylinders:
— longitudinal, without branching (see Figure 10)
— longitudinal, with a side branching at each end which In no case exceeds half the cyhnder circumference (c2 D/2; see Figure 12).
10.5.4 Acceptance criteria
Figures 10.11, and 12 illustrate the satisfactory burst test profiles, and the batches represented by such results shall be accepted.
If the configuration of the fracture does not conform to FIgures 10. 11. or 12 but all other material and mechanical tests are satisfactory, an investigation of the cause of the non-conformity shall be undertaken prior to the acceptance or rejection of the batch.