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Conditions for approval required by: Julien Gauther
Certification of Aerospace Products to international quality Standards
Certification of Aerospace Products to international quality Standards
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In QTP, ISO8788:2000 is mentioned. However, the latest edition of ISO8788 is: ISO8788:2020.
Which one is applicable for this qualification?
Vibration test after exposure to the maximum operating temperature:
As per ISO7481, clause 3.12.1, note d), the test bolt shall have the same tensile strength that of the nut to be tested.
In QTR, test bolt is made out of Inconel 718 with tensile strength equal to 1500 MPa.
However, EN2865 nuts are made out of A286 stainless steel with 1100 MPa strength class.
From my point of view, this is not really an issue, but why Inconel 718 bolts with 1500 MPa UTS were used instead of, for instance, A286 stainless steel bolts with 1100 MPa UTS?
Something to point out: for both vibration tests (at ambient temperature and after baking), this is the same test bolt reference: GALAS00177. However, bolt description is not the same. It is a bit surprising.
Many thanks in advance,
Best regards.
In QTP, ISO8788:2000 is mentioned. However, the latest edition of ISO8788 is: ISO8788:2020.
Which one is applicable for this qualification?
• The last update of this standard is an editorial revision, so no impact on the parts and on the qualification process.
Vibration test after exposure to the maximum operating temperature:
As per ISO7481, clause 3.12.1, note d), the test bolt shall have the same tensile strength that of the nut to be tested.
In QTR, test bolt is made out of Inconel 718 with tensile strength equal to 1500 MPa.
• Yes, I (Howmet) agree. We use a bolt with a strength class greater because we want to be sure to achieve the 100 % of the load required without any failure and any interpretation on the test itself. Indeed when during the test we achieve a failure we are not able to conclude if it is a failure of the bolt or the nut. In these condition no interpretation. Moreover there is no impact on the locking torque because the standard doesn’t required any measurement of this parameter.
However, EN2865 nuts are made out of A286 stainless steel with 1100 MPa strength class.
From my point of view, this is not really an issue, but why Inconel 718 bolts with 1500 MPa UTS were used instead of, for instance, A286 stainless steel bolts with 1100 MPa UTS?
Something to point out: for both vibration tests (at ambient temperature and after baking), this is the same test bolt reference: GALAS00177. However, bolt description is not the same. It is a bit surprising.
• In the last version of the QTR I think that all the data were corrected . GALAS 00177 test bolts were used for measured the locking torque at ambient temperature and after baking, for the tensile test at 80% and for vibration tests. GALAS00846 test bolt in INCONEL 718 were used only for tensile at 100%.
Many thanks for this last update! (QTR 8218C)
Approved on my side.
Best regards.