BS EN 3752-2004 pdf download.Nuts, self-locking, MJ threads, in heat resisting steel FE-PA2601 (A286), MoS2 coated —Classification: 1 100 MPa (at ambient temperature) / 425° C — Technical specification.
This BS EN 3752 specifies the characteristics; qualification and acceptance requirements for self-locking nuts with
MJ threads in FE-PA2601. MoS2 coated, for aerospace applications.
Classification: 1100 MPa 1)/425 °C 2)
It is applicable whenever referenced.
2 Normative references
The following referenced documents ar •ndispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2859-1, Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance quality limit (A QL) for lot-by-lot inspection
ISO 3452. Non-destructive testing — Penetrant inspection — General prmciples
ISO 4288. Geometrical Product Specifications (GPS) – Surface texture: ProfIle method – Rules and procedures for the assessment of surface texture
ISO 5855-2, Aerospace — MJ threads — Part 2: Limit dimensions for bolts and nuts
ISO 7481, Aerospace — Nuts, self-locking, with maximum operating temperature less than or equal to 425 °C — Test methods
EN 2491, Aerospace senes — Molybdenum disuiphide dry lubricants — Coating methods
EN 9133, Aerospace series — Quality management systems — Qualification procedure for aerospace standard parts 3)
ASTM E 112-96, Standard Test Methods for Determining Average Grain Size 4)
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
batch
quantity of finished nuts, of the same type and same diameter, produced from the same material obtained from the same melt, manufactured in the course of the same production cyc’e, following the same .
3.3.3
lap
surface defect caused by folding over metal fins or sharp corners and then rolling or forging them into the surface
3.3.4
inclusions
non-metallic particles originating from the material manufacturing process. These particles may be isolated or arranged in strings.
3.4
test temperature
ambient temperature unless otherwise specified
3.5
simple random sampling
the taking of n items from a population of N items in sucn a way that aN possible combinations ot n items have the same probability of being chosen
3.6
critical defect
a defect that, according to judgement and experience, is likely to result in hazardous or unsafe conditions for
individuals using, maintaining, or depending upon the considered product, or that is likely to prevent
performance of the function of a major end item
3.7
major defect
a defect other than critical, that is likely to result in a failure or to reduce materially the usability of the
considered product for its intended purpose
3.8
minor defect
a defect that is not likely to reduce materially the usability of the considered product for its intended purpose.
or that is a departure from established specification having little bearing on the effective use or operation of
this product
3.9
sampling plan
a plan according to which one or more samples are taken in order to obtain information and possibly to reach
a decision
3.10
limiting quality (LQ10)
in a sampling plan, the quality limit which corresponds to a specified 10 % probability of acceptance
3.14
self-locking torque
the torque to be applied to the nut or bolt to maintain movement of rotation in relation to the associated part. the assembly being under no axial load and the nut locking system being completely engaged with the bolt (minimum protrusion of two pitches including end chamfer)
3.15
seating torque
the tightening torque to be applied to the nut or bolt to introduce or to increase the axial load in the assembly
3.16
unseating torque
the untightening torque to be applied to the nut or bolt to reduce or remove the axial load in the assembly
3.17
breakaway torque
the torque required to start unscrewing the nut or bolt with respect to the associated part, with the nut locking device still fully engaged on the bolt, but after the axial load in the assembly has been removed by unscrewing half a turn followed by a halt in rotational movement
3.18
wrench feature torque
the torque to be applied to the wrenching feature of the nut
4 Quality assurance
4.1 Qualification EN 9133
Qualification Inspections and tests (requirements, methods, numbers of nuts) are specified in Table 1. They shall be carried out on:
each type and diameter of nut:
— 46 nuts selected from a single inspection lot by simple random sampling.
The test programme may possibly be reduced, or the qualification of a nut be granted without inspection or testing. Any such decision shall be based on the results obtained on similar types and diameters of nuts provided that the design and manufacturing conditions are identical.
Table 2 indicates the allocation of nut samples for the inspections and tests.BS EN 3752-2004 pdf download.