Impact Tests for Stainless Steel

[curiousguy]

We are not establishing this procedure for any particular job. Will this procedure still be valid for welding 316L for a job that requires WPS/PQR to be qualified as per PED? Or would it still require the PMA to be done?

[mariog]

I’ll quote the following document, hoping this one will help you...

[link Point to another website Only the registered members can access]
"As required by the Pressure Equipment Directive 97/23/EC (PED) Annex I section 4.2, the pressure equipment manufacturer is responsible for preparing documentation for materials to be used for pressure equipment in categories I to IV. For pressure equipment in categories III and IV this documentation is submitted to the Notified Body in charge of the conformity assessment for the equipment so they can perform an appraisal of the particular material with regard to the pressure equipment, the intended use and applicable design rules.
[……]
Decisions made concerning a specific material for use in a specific sets of conditions, do not need to be repeated. However, manufacturers and where applicable notified bodies must ensure the PMA is suitable for its application and that this is recorded in the technical documentation.
Pressure equipment manufacturers may utilise PMAs prepared and supplied by another manufacturer, e.g. the manufacturer of an assembly, on condition that the PMA is reviewed and adopted by the PE manufacturer and where applicable the NB in charge of the conformity assessment procedure, to ensure accuracy of the document and suitability for the application.”

I understand you are trying to perform a general document; however it will be a day when you’ll need to present to Notified Body all necessary documents, including documents for materials used (particularly a PMA, if any).
As you can see, PMA is not viewed as a "general" document until the first approval and normally, PMA is related to a specific job. After approval, PMA gets a kind of generality, as you can see above.

And quite strange, Notified Body cannot perform a PMA as a general document..
Guideline 7/21 Question: May a notified body perform a particular material appraisal at the request of a material manufacturer? Answer: No. The PMA is performed on request of a pressure equipment manufacturer.


About impact testing of 316L, it is worth to consider paragraph 2 of Guideline 7/17
The exception concerns “ductile materials which are not subject to a ductile/brittle transition at the foreseeable conditions the equipment will be exposed to”.
Examples of such materials are: austenitic stainless steels.
But once again, it’s up to Notified Body to consider or not your particular case as "exception"…