TCM 1 789-(MCR) – Arconic St Cosme en Vairais (FR) PQ351 Subcontract Surface treatment

3 Replies to “TCM 1 789-(MCR) – Arconic St Cosme en Vairais (FR) PQ351 Subcontract Surface treatment”

1. QTR, clause 2.2.
   Thread area cross-section picture shows a cadmium thickness a bit below 5 µm (4,69 µm if I am not mistaken since it is a bit difficult to read the value).
   EN2753 requires a cadmium thickness greater or equal to 5 µm on threads.
   If observed value is really below 5µm in thickness, why it is considered compliant?

   QTR, clauses 2.3 and 2.4.
   Baking process was done by LISI to remove hydrogen after cadmium plating.
   However, as per EN2133 clause 9, a stress relief heat treatment is required on parts with 1100 MPa UTS, but this stress relief operation before cadmium plating is not required for fasteners which haven’t been cold worked or machined after the heat treatment operation (clause 9, note a)).
   The associated flow chart shows that there is no machining or cold working operations after heat treatment.
   Could you please confirm?
   Many thanks in advance.
   Have a good day.
   Julien

   Reply

   1. Julien.

      See below the answers of the Howmet (Arconic) St-Cosme.

      The values measured on the threads are 6.7 – 6.23 – 4. 69 so the average measure is 5.877 µm so we consider that the value is compliant . On the bearing face value measured are 7.4 – 6.49 µm average 6.945 µm .

      In the router there is no machining or cold working operation after the Heat treatment operation . The only operation after heat treatment is CND , so stress relief is not required.

      If there still any questions please let me know.

      Regards
      Kees

      Reply

2. Kees,

   Everything is clear, thank you.
   No additional question, so, qualification approved on my side.
   Regards,
   Julien

   Reply