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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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Recess removal torque:
I agree with justification written in “Standard issue” section.
However, ISO9152 table 9 covers a diameter range from 2 to 12.
EN4178 diameter range is from 030 (recess code 10) to 120 (recess code 55).
EN3905 is applicable for a diameter range from 050 (recess code 27) to 10 (recess code 55).
Thus, by considering only EN3905, some recess codes are missing.
Therefore, in my opinion, ISO9152 table 9 shall be considered applicable as well.
Hopefully, recess removal torque values requirements in ISO9152 are lower than those in EN3905 (for the same recess code/diameter) except for MJ12.
What are your thoughts on this topic?
Hydrogen content:
According to Process Flow chart, this test was carried out just afer heat treatment.
However, these bolts are blue anodized.
Anodizing process should appear on Process Flow chart as well as it is the case for dry film lubrication.
Anodizing is a source of hydrogen (due to electrochemical reaction between titanium alloy and sulfuric acid).
Thus, could you please check if hydrogen content was actually carried out after heat treating operation or on finished parts? (at least, after anodizing).
This bolt is dry film lubricated: molybdenum disulfide with organic compounds.
For this reason (organic compounds contain hydrogen), when material is removed from head of finished bolts to carry out this test, pay attention, in that case, to the fact that dry film lubricant may be present in samples by accident.
Thus, higher hydrogen values than expected may be measured.
Many thanks in advance
Best regards
Julien
Some addtional comments:
Process flow chart: could you please add “Tension fatigue test”? (we have tensile and double shear tests mentioned on it).
Minor comments (just for “improvement” I would say) on Test Report, not blocking:
Replace “Thermical treatment” by heat treatment
“Essai de Fatigue / Stress rupture test”: Essai de fatigue / Fatigue test.
Many thanks again
Best regards
Julien
Question Recess removal torque:
I agree with justification written in “Standard issue” section.
However, ISO9152 table 9 covers a diameter range from 2 to 12.
EN4178 diameter range is from 030 (recess code 10) to 120 (recess code 55).
EN3905 is applicable for a diameter range from 050 (recess code 27) to 10 (recess code 55).
Thus, by considering only EN3905, some recess codes are missing.
Therefore, in my opinion, ISO9152 table 9 shall be considered applicable as well.
Hopefully, recess removal torque values requirements in ISO9152 are lower than those in EN3905 (for the same recess code/diameter) except for MJ12.
What are your thoughts on this topic?
Answer :
I agree with your comment . In fact even taken into account ISO 9152 and EN 3905 there is a missing between 12 to 27. From my point of view ,the best should be to complete the ISO with all recess codes. It will be easier for the interpretation .
Question Hydrogen content:
According to Process Flow chart, this test was carried out just after heat treatment.
However, these bolts are blue anodized.
Anodizing process should appear on Process Flow chart as well as it is the case for dry film lubrication.
Anodizing is a source of hydrogen (due to electrochemical reaction between titanium alloy and sulfuric acid).
Thus, could you please check if hydrogen content was actually carried out after heat treating operation or on finished parts? (at least, after anodizing).
This bolt is dry film lubricated: molybdenum disulfide with organic compounds.
For this reason (organic compounds contain hydrogen), when material is removed from head of finished bolts to carry out this test, pay attention, in that case, to the fact that dry film lubricant may be present in samples by accident.
Thus, higher hydrogen values than expected may be measured.
Answer :
The H2 content is doing after heat treatment ( 2 samples) and after surface treatment ( 1 sample) . The results are uploaded in the “supplementary documents box” ( doc F0000172 2220200118 OF222060353 H2 ). In fact there is no effect of the surface treatment of H2 content which is conform to a anodic process ( the H2 is released on the cathode). It is also conform with some tests that AH as made in the past on Decomatic parts. The manufacturing flow chart has been updated with the two H2 content tests.
Some additional comments:
Process flow chart: could you please add “Tension fatigue test”? (we have tensile and double shear tests mentioned on it).
Minor comments (just for “improvement” I would say) on Test Report, not blocking:
Replace “Thermical treatment” by heat treatment
“Essai de Fatigue / Stress rupture test”: Essai de fatigue / Fatigue test.
Answer:
Flow chart updated taken into account your remarks
in addition I have added in “supplementary document box” the fatigue test results reports
Hi Daniel,
Many thanks for all your detailed answers.
I am happy with all of them.
I agree with your comment on H2 content.
However, cathodes in sulfuric acid bath shall be far enough away from titanium parts (to avoid any risk of adsorption). In addition, hydrogen may be dissolved in the bath.
Another source of hydrogen is surface preparation before anodizing. If titanium parts undergo a fluonitric pickling, hydrogen is directly present on the surface.
Anyway, just something to point out and finally, qualification approved from my side.
Best regards
Julien