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Certification of Aerospace Products to international quality Standards
Certification of Aerospace Products to international quality Standards
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CoC calls out both EN3005 (top of document) and prEN3005 (section “conform to”). Which issue of EN3005 has been applied?
CoC states that these nuts have been axial tensile tested. Actual values range from 7925 daN to 8118 daN.
As per EN3005, minimum tensile load for MJ8 is 47,9 kN.
By using formula in EN3005, table 5:
UTS = Load/stress area.
So: 79250/39,56 = 2003 MPa and 81180/39,56 = 2052 MPa
These calculated UTS based on actual tensile loads are really high since minimum UTS is 1210 MPa and this material cannot reach this UTS level.
Moreover, these nuts did not break at these values (7925 daN and 8118 daN).
Could you please confirm axial load values in this CoC?
Many thanks in advance,
Best regards.
Julien
You will find below the reply from our laboratory manager :
“We work with partial teams so we apologize for the delay.
I confirm the axial tensile results are high but are the actual values and meet the spec requirements EN3005. The 3 tests we have just performed give the same values.
We perform the tests with test bolts of alloy steel material high UTS level 1800MPa mini. ( Results around 7000daN) The nuts didn’t break but the test bolt did. If we had performed the same tests with test bolts of material lower UTS level ( waspaloy 1210 Mpa mini ) we would have obtained lower values around 5000 daN as we found on the previous batches.
Anyway the values comply with the requirements and the tests carried out in accordance with the spec in terms of test bolt. Indeed it is only stipulated that we must use test bolts with tensile strength class greater than of the nut (1210Mpa) and no specific requirement of material test bolt. No more caracterisitics.
For your information the UTS of the nut is 1330 Mpa for 1210 Mpa required.”
Hello Mrs. Faix,
Thank you for replying.
It is clear now.
Have a good day.
Regards.
Julien