ISO 9809-4-2014 pdf free download

ISO 9809-4-2014 pdf free download.Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and testing — Part 4:Stainless steel cylinders with an Rm value of less than 1 100 MPa
Bouteilles a gaz — Bouteilles a gaz rechargeables en acier sans soudure — Conception, construction et essais — Partie 4: Bouteilles en acier inoxydable avec une valeur Rm inférleure a I 100 MPa.
6.3.2 The finished cylinders made from the ferritic or martensitic steel categories shall be quenched and tempered, except if they are cold worked (see ,4).
6.3.3 For the ferritic and martensitic steels, the heat treatment process shall achieve the required mechanical properties.
63.4 The actual temperature to which a type of steel is subjected to obtain a given tensile strength shall not deviate by more than 30 °C from the temperature specified by the cylinder manufacturer.
6.4 Cold working or cryoforming
Cold working or cryoforming is used to enhance the finished mechanical properties in certain stainless steel materials.
For cylinders that are subjected to cold working or to the cryoforming process, all the heat treatment requirements refer to the cylinder preform operations. Cold worked or cryoforined cylinders shall not be subjected to any subsequent heat treatment.
6.5 Failure to meet test requirements
In the event of failure to meet the test requirements, retesting or reheat treatment and retesting shall be carried out as follows to the satisfaction of the inspector:
a) If there is evidence of a fault in carrying out a test, or an error of measurement, a further Lest shall be performed. If the result of this test is satisfactory, the first test shall be ignored.
b) If the test has been carried out in a satisfactory manner, the cause of test failure shall be identified,
1) If the failure is considered to be due to the heat treatment applied, the manufacturer can subject all the cylinders implicated by the failure to a further heat treatment, e.g. If the failure is in a test representing the prototype or batch cylinders. Test failure shall require reheat treatment of all the represented cylinders prior to retest ing.
Whenever the cylinders are reheat treated, the minimum guaranteed wall thickness shall be maintained.
Only the relevant prototype or batch tests needed to prove the acceptability of the new batch shall be performed again. If one or more tests prove even partially unsatisfactory, all the cylinders of the batch shall be rejected.
2) If the failure is due to a cause other than the heat treatment applied, all the cylinders with imperfections shall be either rejected or repaired such that the repaired cylinders pass the test(s) required for the repair. They shall then be reinstated as part of the original batch.ISO 9809-4-2014 pdf free download.