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Certification of Aerospace Products to international quality Standards
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PFC rev 04:
MPI is considered as Key operation is placed after cadmium plating.
In QTR EN4073-100 Appendix A till F, we have the same revision of PFC, but MPI is not considered as Key Operation in this one. Moreover, it is mentioned that non-key operations may be produced on different sequence.
Could you just please confirm that MPI is done before cadmium plating?
QTR, recess removal torque. Could you just please confirm the number of cycles applied for each tested bolt?
Since related bolt to this qualification is EN4073H100016, this qualification is limited to EN4073 bolt with diameter MJ10 and maximum grip length (smooth shank) equal to 19 mm. Indeed, tensile and double shear tests on bolts were not performed, because EN4073H100016 is too short (see ISO7689, clauses 5.4.1 and 5.4.2). Qualification scope (appendix A) is in line with this limitation.
PFC rev 04 shows a stress relief process before cadmium plating as required by EN2133.
If I am not wrong, I did not see any curve or statement on stress relieving before cadmium plating.
Could you please add this if missing?
(Otherwise, we have information/curve for embrittlement relief after cadmium plating)
Many thanks in advance.
Regards.
Julien
The answers to the questions and/or comments are added below:
PFC rev 04:
MPI is considered as Key operation is placed after cadmium plating.
In QTR EN4073-100 Appendix A till F, we have the same revision of PFC, but MPI is not considered as Key Operation in this one. Moreover, it is mentioned that non-key operations may be produced on different sequence.
Could you just please confirm that MPI is done before cadmium plating?
MPI performed after cadmium plating, not compliant to the ISO7689 nota “a” but, here is an extract from the ASTM-E1444/1444M:
With the cadmium plating thickness between 8µm and 14µm we are compliant with clause 5.4.3.2 from ASTM-E1444/1444M.
5.4.1 Perform magnetic particle examination prior to shot peening (to provide a beneficial compressive layer) and prior to
applying protective finishes such as priming, painting, plating (see 5.4.3 through 5.4.3.5) or other coatings.
5.4.2 In-process examinations may not be substituted for final examination.
5.4.3 Plating and Coatings—Examine parts which will receive either a plating or coating as follows:
5.4.3.1 Examination is required prior to all nonelectroplated coatings.
5.4.3.2 Electroplated surfaces with a final plating thickness of 0.0008 in. [0.02 mm] or less shall be examined either before
or after electroplating, or grinding, or both, of electroplated surfaces.
5.4.3.3 Electroplated surfaces with a final plating thickness of between 0.0008 in. [0.02 mm] and 0.0050 in. [0.13 mm]
shall be examined both before and after electroplating, or grinding, or both, of electroplated surfaces.
(1) Electroplated surfaces with a final plating thickness of 0.0050 in. [0.13 mm] or greater shall be examined before
electroplating, or grinding, or both, of electroplated surfaces.
We also have proposed an update of the ISO7689 in which MPI could be performed either prior or after plating.
QTR, recess removal torque. Could you just please confirm the number of cycles applied for each tested bolt?
15 cycles performed. (conform)
Since related bolt to this qualification is EN4073H100016, this qualification is limited to EN4073 bolt with diameter MJ10 and maximum grip length (smooth shank) equal to 19 mm. Indeed, tensile and double shear tests on bolts were not performed, because EN4073H100016 is too short (see ISO7689, clauses 5.4.1 and 5.4.2). Qualification scope (appendix A) is in line with this limitation.
OK
PFC rev 04 shows a stress relief process before cadmium plating as required by EN2133.
If I am not wrong, I did not see any curve or statement on stress relieving before cadmium plating.
Could you please add this if missing?
Curves has been uploaded in “Additional Documents” are in attached file.
Assume that the questions have been answered sufficiently.
If there are still any questions, please don’t hesitate to contact me.
Regards
Kees
Thank you for your detailed reply Kees!
It is clear for me now, especially for MPI.
Just one more thing:
ASTM E1444/E1444M states:
Clause 5.4.3.4 Use caution when examining parts with an electroplated
nickel coating as indications may form from the resulting leakage fields within the nickel plating itself.
So, in the case of nickel strike before cadmium plating (to promote cadmium adhesion), do we consider that nickel strike can distort MPI?
Nickel strike is commonly performed on stainless steels or nickel alloys parts.
Do we have nickel strike on these steel parts?
Obviously, nickel strike deposit is really thin and may not affect MPI.
Subject to watch in my opinion.
Regards,
Julien
Thank you Julien.
Appreciate your well-founded comment, because it is indeed a point to watch out for.
Will definitely pass this point on to Arconic to get their focus on that (next to mine).
Regards
Kees