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Conditions for approval required by: Philippe Canteau
Certification of Aerospace Products to international quality Standards
Certification of Aerospace Products to international quality Standards
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Conditions for initial qualification of prEN3713-100 nuts under ISO5858 technical specification :
• EN3713 product standard has been cancelled by ASD-STAN several years ago due to a qualification issue for EN3713-120 nut in 2012 by ASD-CERT (qualification 34). This qualification of prEN3713-100 nut will be valid after prEN3713 product standard is re activated official by ASD-STAN.
• There is no statement of conformity to EN3330 or EN3704 material standards as called by prEN3713 product standard. Please provide ASD-CERT with this equivalence compared to mentioned AT1593619 material used by the manufacturer.
• Hardness: the report states that no hardness is required for steel material. However EN3330 requires 390 < HV5 < 430. The HV5 results seems OK with those values. Please clarify.
• Material: EN3330 requires step quench in a salted bath with temperature between 850°C and 860 °C. Please provide ASD-CERT with this evidence for used material.
• Marking and surface condition: 100 nuts have been controlled. ISO5858 states that for a batch of 1796 parts, 125 sample parts have to be visually controlled. Please clarify.
• Dimensional inspection: 20 nuts have been controlled. ISO5858 states that for a batch of 1796 parts, 125 parts have to be controlled. Please clarify.
• Self-Locking test: 100 nuts have been tested. ISO5858 states 125 nuts to be tested for a batch of 1796 parts. Please clarify.
• 15-cycle and 3-cycle tests: 8 nuts have been tested. ISO5858 states 13 nuts to be tested for a batch of 1796 parts. Please clarify.
• Packing. Please provide ASD-CERT with a photo of a package.
• Non-magnetism test was not performed for those stainless steel nuts as per ISO 5858. Please provide ASD-CERT with a justification.
• Stress embrittlement was not performed. Please provide ASD-CERT with a justification (Hardness < 44 HRC ?).
Hi Philippe
Below is the joint response of Howmet and me on your comments and questions.
• EN3713 product standard has been cancelled by ASD-STAN several years ago due to a qualification issue for EN3713-120 nut in 2012 by ASD-CERT (qualification 34). This qualification of prEN3713-100 nut will be valid after prEN3713 product standard is re activated official by ASD-STAN.
We Howmet never officially received letter from ASD/CERT or ASD/ STAND which stipulated that the standard EN3713 was cancelled. We receive a lot order for this family of products from many customers. SO I am very surprised. If I understand correctly the standard will be cancelled due to an issue because a manufacturer fails the qualification of – 120. Do you have more information about this fail because we ? which test? Etc.
• There is no statement of conformity to EN3330 or EN3704 material standards as called by prEN3713 product standard. Please provide ASD-CERT with this equivalence compared to mentioned AT1593619 material used by the manufacturer.
On the COC of thr material AT1593619 batch the supplier Brown Europe certify that this raw material is conform to our internal specification SAM0026 -( see additional documents enclosed) .This internal specification refers to EN3330 ( see higliht in our internal specification).
• Hardness: the report states that no hardness is required for steel material. However EN3330 requires 390 < HV5 325°C /AC or other equivalent heat treatment. The heat treatment performed in HFS is an equivalent heat treatment austempering process (austenitization around 870°C follow by a salt bath quenched at 390°C to achieved the right performances).
• Marking and surface condition: 100 nuts have been controlled. ISO5858 states that for a batch of 1796 parts, 125 sample parts have to be visually controlled. Please clarify.
In this case it is a “Qualification of the nut” (ISO5858, point 4.1.2.) and not a “Production acceptance of nuts” (ISO5858, point 4.1.3.). ISO5858, point 4.2. “Qualification inspection and test conditions” clearly indicates that Table 1 should be used for the qualification. Looking at table 1 point 5.3 “Surface condition” and point 5.4, “Marking” gives a sample size of 100 in the column “Test category” for the Qualification. So the tested quantity of 100 pieces is correct. The 125 pieces mentioned in the comment would have been correct if it had been a “Product acceptance test” and table 11 and 12 had to be used.
• Dimensional inspection: 20 nuts have been controlled. ISO5858 states that for a batch of 1796 parts, 125 parts have to be controlled. Please clarify.
See above. Table 11 and 12 are not applicable for this qualification test. So the tested quantity, see table 1, of 20 pieces is correct. (ISO5858, table 1, point 5.5.1.)
• Self-Locking test: 100 nuts have been tested. ISO5858 states 125 nuts to be tested for a batch of 1796 parts. Please clarify.
See above. Table 11 and 12 are not applicable for this qualification test. So the tested quantity, see table 1, of 100 pieces is correct. (ISO5858, table 1, point 5.6.7.1.) Presumably by “self-locking test” is meant the “Presence of locking element”.
• 15-cycle and 3-cycle tests: 8 nuts have been tested. ISO5858 states 13 nuts to be tested for a batch of 1796 parts. Please clarify.
See above. Table 11 and 12 are not applicable for this qualification test. So the tested quantity, see table 1, of 8 pieces is correct. (ISO5858, table 1, point 5.6.7.2.1.)
• Packing. Please provide ASD-CERT with a photo of a package.
The parts will package in a sealed plastic bag with the label that you can find a photo in the QTR enclosed . I cannot include a photo with label in the test report because I am not able to properly complete the label until the parts are not qualify due to the fact that the label is complete automatically at the shipment .
• Non-magnetism test was not performed for those stainless steel nuts as per ISO 5858. Please provide ASD-CERT with a justification.
Table 1, point 5.1.6 “Non-Magnetism” is not applicable for this type of nut. See de “d” and in the table on page 15 under “d” it is stated: “Inspection applicable only to nuts made of stainless steel”
• Stress embrittlement was not performed. Please provide ASD-CERT with a justification (Hardness < 44 HRC ?).
Table 1, point 5.6.3 “Stress embrittlement” is not applicable for this type of nut. See de “j” and in the table on page 15 under “j” it is stated: “Test applicable only to nuts heat-treated to a hardness equal to or greater than 44 HRC”
Regards
Kees
EN3713 product standard has been cancelled by ASD-STAN several years ago due to a qualification issue for EN3713-120 nut in 2012 by ASD-CERT (qualification 34). This qualification of prEN3713-100 nut will be valid after prEN3713 product standard is re activated official by ASD-STAN.
Answer is not acceptable. This is the manufacturer’s responsibility to check that the products they manufacture against a standard is not cancelled. ASD-CERT has no obligation to inform the manufacturers. I can approve only if the prEN3713 product standard is re activated by ASD-STAN. See ASD-CERT Quality Manual.
There is no statement of conformity to EN3330 or EN3704 material standards as called by prEN3713 product standard. Please provide ASD-CERT with this equivalence compared to mentioned AT1593619 material used by the manufacturer.
Answer accepted.
Hardness: the report states that no hardness is required for steel material. However EN3330 requires 390 < HV5 325°C /AC or other equivalent heat treatment.
Answer accepted.
Marking and surface condition: 100 nuts have been controlled. ISO5858 states that for a batch of 1796 parts, 125 sample parts have to be visually controlled. Please clarify.
Answer Accepted.
Dimensional inspection: 20 nuts have been controlled. ISO5858 states that for a batch of 1796 parts, 125 parts have to be controlled. Please clarify.
Answer accepted.
Self-Locking test: 100 nuts have been tested. ISO5858 states 125 nuts to be tested for a batch of 1796 parts. Please clarify.
Answer accepted.
15-cycle and 3-cycle tests: 8 nuts have been tested. ISO5858 states 13 nuts to be tested for a batch of 1796 parts. Please clarify.
Answer accepted.
Packing. Please provide ASD-CERT with a photo of a package.
Other manufacturers provide ASD-CERT with a photo of an example of packing of similar parts. However explanation is accepted.
Non-magnetism test was not performed for those stainless steel nuts as per ISO 5858. Please provide ASD-CERT with a justification.
Answer with justification accepted.
Stress embrittlement was not performed. Please provide ASD-CERT with a justification (Hardness < 44 HRC ?).
Answer accepted.
After review of the standard prEN3713, the Mechanichal – Fasteners Committee decided to ask ASD-STAN to re-activate and revise it. We believe the material classification of 1550 MPa is wrong:
• The surface treatment of this part, as called out in prEN3713 is to EN2133 which is Cadmium plating of steels with specified tensile strength ? 1 450 MPa, copper, copper alloys and nickel alloys.
o As you can see this is for Cad plated steel part with a classification of ? 1450 MPa.
o It is possible to Heat Treat these parts to a strength of 1500 MPa but there is a chance of introducing Hydrogen Stress embrittlement, which is not good or wanted. This should be taken into consideration when ASD-STAN will revise this standard.
For this very reason, the risk of Hydrogen Stress embrittlement, the technical committee decided no qualification should be granted against prEN3713 in its current state. Therefore, we are obliged to decline qualification 828.