IS0 20703:2006 pdf download.Gas cylinders — Refillable welded aluminium-alloy cylinders -Design,construction and testing.
4.1.2 Examples of the alloys most commonly used for the fabrication of gas cylinders are given in Table I
4.1.3 After the complehon of all welding (including that of the attachments) and before the hydraulic test,
each cylinder shall be heat treated if required to meet the design criteria,
4.2 Heat treatment
4.2.1 General
Any welding on the pressure-bearing part shall take place before any final heat treatment (see 6.2).
4.2.2 Heat-treatable alloys
The manufacturer shall specify on the new design type testing documentation, where required, the solution heat treatment and artificial ageing temperatures and the times for which the cylinders have been held at those temperatures. The medium used for quenching after solution heat treatment shall be identified.
Unless the alloy is subjected to a temperature in excess of 400 C Jring the formwig process, a stabilizing treatment shall be carried out and the temperature, and time at temperature, shall be identified by the manufacturer.
However, the stabilizing treatment is not necessary for a cylinder of which the wall thickness in 5.2 is calculated with the minimum guaranteed yield stress value of the 0-tempered alloy (or the alloy annealed for complete re-crystallization before forming of cylinder, as defined in ISO 2107).
If the cylinder Is Intended for dissolved-gas service It shall only be used in the fully annealed condition, I.e. the minimum guaranteed properties used for the material shall consider the heat treatment to be applied, e.g. during the massing operation.
4.2.3 Non-heat-treatable alloys
The manufacturer shall specify on the new design type testing documentation, where required, the type of metal forming operation carried out (extrusion, drawing. ironing, head forming, etc.). Unless the alloy is subjected to a temperature in excess of 400 °C dunng the forming process. a stabilizing treatment shall be carried out and the temperature, and time at temperature, shall be identified by the manufacturer.
4.1.3 After the complehon of all welding (including that of the attachments) and before the hydraulic test,
each cylinder shall be heat treated if required to meet the design criteria,
4.2 Heat treatment
4.2.1 General
Any welding on the pressure-bearing part shall take place before any final heat treatment (see 6.2).
4.2.2 Heat-treatable alloys
The manufacturer shall specify on the new design type testing documentation, where required, the solution heat treatment and artificial ageing temperatures and the times for which the cylinders have been held at those temperatures. The medium used for quenching after solution heat treatment shall be identified.
Unless the alloy is subjected to a temperature in excess of 400 C Jring the formwig process, a stabilizing treatment shall be carried out and the temperature, and time at temperature, shall be identified by the manufacturer.
However, the stabilizing treatment is not necessary for a cylinder of which the wall thickness in 5.2 is calculated with the minimum guaranteed yield stress value of the 0-tempered alloy (or the alloy annealed for complete re-crystallization before forming of cylinder, as defined in ISO 2107).
If the cylinder Is Intended for dissolved-gas service It shall only be used in the fully annealed condition, I.e. the minimum guaranteed properties used for the material shall consider the heat treatment to be applied, e.g. during the massing operation.
4.2.3 Non-heat-treatable alloys
The manufacturer shall specify on the new design type testing documentation, where required, the type of metal forming operation carried out (extrusion, drawing. ironing, head forming, etc.). Unless the alloy is subjected to a temperature in excess of 400 °C dunng the forming process. a stabilizing treatment shall be carried out and the temperature, and time at temperature, shall be identified by the manufacturer.
