ISO 5858:1999 download.Aerospace — Nuts, self-locking, with maximum operating temperature less than or equal to 425 °C — Procurement specification.
ISO 5858 specifies the required characteristics for metric self-locking nuts, with MJ threads, for use in aerospace construction at a maximum temperature less than or equal to 425 °C.
It is applicable to nuts as defined above, provided that reference is made to ISO 5858 In the relevant definition document.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of ISO 5858. For dated references, subsequent amendments to. or revisions of, any of these publications do not apply. However, parties to agreements based on ISO 5858 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 691:1997, Assembly tools for screws and nuts — Wrench and socket openings — Tolerances for general use. ISO 1463:1982, Metallic and oxide coatings — Measurement of coating thickness — Microscopical method.
ISO 2859-1:1999, Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance quality limit (AOL) for lot-by-lot inspection.
ISO 3452:1984, Non-destructive testing — Penetrant inspection — General princØles.
ISO 3887:1976, Steel, non-alloy and low-alloy— Determination of depth of decarburization.
ISO 4288:1996, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Rules and procedures for the assessment of surface texture.
ISO 5855-2:1999, Aerospace — MJ threads — Part 2: Limit dimensions for bolts and nuts. ISO 7403:1998, Aerospace — Spline drives — Wrenching configuration — Metric series.
ISO 7481:), Aerospace — Self-locking nuts with maximum operating temperature less than or equal to 425 °C — Test methods.
ISO 7870:1993, Control charts — General guide and introduction.
ISO 8258:1991. Shewhart control charts.
ISO 8788:—. Aerospace — Nuts, metric — Tolerances of Mm and posritori
ISO 9002:1994. Quality systenis — Model br qualIty assurance in production. installation and servicing.
ISO 9227:1990. Corrosion tests in artificial atmospheres — Salt spray tests.
ISO(TR 13425:1995, Guide for the selection of statistical methods lI, slandarclzaftov, and specification.
3 Terms and definitions
For the purposes of ISO 5858, the following Ierms and definitions apply.
3.1
definition document
document speofying all the requirements for nuts, I.e.:
— metaurgical.
— geometrical and dWnenseonal:
— functional (strength and tempelalure classes)
NOTE The dellnitlon document may be an International Standard, a national standard, or an in’house standard or &awing
3.2
finished nut
nut ready lot use. Inclusive of any possible treatments and/or surface coatings, as specthed in the definition document
3,3
batch
definite Janti1y 01 some commodity manufactured or produced under conditions which are presumed to be Lmiform
NOTE For the purposes of a”ws Intena1ional Standard. a belch l a quanidy of tinished nuts, of the same type and same dbameler. proiced from a materIal obtaeied from the same melt. manufactured In the course of the same productIon cycle. following the same manufacturing route and having undergone all the relevant heat treatments and surtace treatments
3.4
crack
rupture in the material which may extend in any direction and which may be lnlercrystaltlne or transcrystalline in character
seam
open surface detect resulting from extension of the metal
3.6
lap
folding over of unwelded metal that can arise when the material is formed (&aw.ng or In the finished product (pressing or forging)
3.15
seft-locking torque
torque to be applied to the nut or bolt to maintain Its movement of rotation in relation to the associated part, the assembly being under no axial load and the nut-locking system being oonletely engaged with the boll (two pitches minimum protrusion, induding the end chamfer)
3.16
seating torque
tightening torque to be applied to the nut or bolt to introduce or to Increase the axial load in the assembly
3.17
unseatIng torque
untighlening torque to be applied to the nut or bolt to reduce or remove the axial load in the assembly
3.18
breakaway torque
torque required to start unscrewing the nut or bolt with respect to the associated part, with the nut-locking device stiU hilly engaged on the bolt, but after the axial load in the assembly has been removed by unscrewing haM a turn followed by a halt in rotational movement
3.19
Wrench torque
tightening and untigtitening torques which the driving feature of the rail has to withstand repeatedly without any permanent deformation whicii would prevent the appropriate wrench from being used or predude re-use of the nut
4 Quality assurance
4.1 General
4.1.1 Manulaclurer’s approval
The manufacturer shaM conform to the quality assurance and approval procechjres defined by ISO 9002.
The purpose of these procedures is to ensure that a manufacturer has a quality system and the capability for continuous production of nuts complying with the specified quality requirements.
Approval of the manufacturer shall be granted by the Certification Authorities, or their appointed representative, who may be the prime contractor.
4.1.2 QualifIcation of nuts
The purpose of qualification inspections and tests of nuts is to check that the design and manufacturing conditions for a nut allow it to satisfy the requirements of this International Standard.
Qualification of the nuts shall be granted by the Certr[ioatlon Authorities in the purchasers country, or their appointed representative, who may be the prime contractor.
4.1.3 ProductIon acceptance of nuts
The purpose of production acceptance Inspection and tests of a nut Is to check, as simply as possible, using a method which is inexpensive but the most representative of the actual conditions of use, with the uncertainty inherent In statistical sarepling. that the nuts satisfy the requirements of ISO 5858.
Production acceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility. The manufacturer is responsible for the quality of the nuts manufadured
4.2 QualIfication inspectton and test conditions
Ouahficaaon inspections arid tests frequirements, methods, numbers of nuts) are specified In Table 1. They shall be carried Out on:
— each type and diameter of nul:
— 100 nuts selected from a single batch by simple random saispng.
The test programme may possibly be reduced, or qualification of a nut granted, without inspection or testing: any such decasion shall be based on the results obtained on similar types and diameters of nuts provided that the design and manufacturing conditions are identical.
The inspections and tests shall be repeated on any nut if the splier or the rnanutactunng conditions have changed.
Qualification inspections and tests are summarized in Table 2.
4.3 Production acceptance Inspection and test conditions
Production acceptance inspections and tests (reqLsrements, methods, numbers of nuts) are specified in Table 1. They shall be carried out on each batch. Nuts from the batch to be tested shall be selected by simple random sampling.
Each nut may be subjected to several inspections or tests
The nuts to be subjected to destructive inspections or tests may be those on which non-destructive inspections or tests have been carried out.
It a more stringent inspection is deemed necessary, as or part of the qualification inspections and tests may be performed dunng the production acceptance inspections and testing. In this case, the number of nuts submitted is the same as that submitted for cjaJillcation inspections and tests.
Batches declared unacceptable after the production acceptance Inspections and tests shall be submitted for reinspection or testing only after all the defective units have been removed andior defects have been corrected. In this case, the attrlixite(s) which caused the rejection shall be verified using a sample of twice the normal size with the same number of defective items acceptable.
Production acceptance inspections and tests are summarized In Table 2.
4.4 Use of “statistical process control (SPC)”
Where a characteristic Is obtained by a coniroled statistical process, the manufacturer has the poembility. in order to declare conformity of the characteristic, of refraining from the final systematic sampling provided for In ISO 5858. If he is capable of formally ustifying this choice by using ISOTR 13425 and the standards quoted In It as a basis.
This justification will include the toilowwig phases:
— analysis of the product’s key characteristics:
— analysis of the rislis for cacti implemented process;
— determination of the parameters andJor characteristics to be respected under SPC:
— determination of the capabilities of each process:
— drawing up an inspection plan and integration in the manufackwing process:
— drawing up of routes and control charts (ISO 7966, ISO 7870. ISO 8258).