Overview - ISO 8168:2016 (Aerospace bolts, MJ threads, heat- and corrosion‑resisting steel, strength class 1 100 MPa)
ISO 8168:2016 is an ISO procurement specification for aerospace bolts with MJ threads made from heat- and corrosion-resisting steel of strength class 1 100 MPa. The standard defines characteristics, quality‑assurance requirements and test methods for bolts intended for aerospace construction and is applicable whenever referenced in a definition document (for example, an OEM drawing or in‑house standard).
Key topics and technical requirements
- Material and mechanical properties
- Material conformity required as specified in the definition document; tensile and double‑shear strength tests referenced (ISO 7961, ISO 6892‑1).
- Strength class specified as 1 100 MPa.
- Manufacturing processes
- Bolt heads formed by hot or cold forging; hot forging equipment must maintain a constant temperature below 1 090 °C.
- Forged blanks heat‑treated (no more than two heat‑treatment cycles) and threads formed by rolling after full heat treatment.
- Surface finishing, coatings and roughness to meet the definition document and ISO 4288 surface texture rules.
- Quality assurance and inspection
- Definition of batch and inspection lot, sampling plans and defect classifications (critical, major, minor).
- Qualification inspection: typically 25 bolts selected by simple random sampling for each type and diameter unless reduced by equivalence justification.
- Production acceptance inspections on each lot, with procedures for rejected lots and re‑inspection (including double sample size for affected attributes).
- Requirement to retain quality documentation for a minimum of 10 years.
- Statistical process control (SPC)
- Option to substitute final lot sampling when SPC is validated and approved (ISO/TR 13425 and ISO 7870 series guidance).
- Non‑destructive and destructive tests
- Penetrant testing (ISO 3452‑1), surface inspection and specified destructive tests (tensile, shear) with allowances for when bolts cannot be directly tested (use of test bars).
Practical applications and users
ISO 8168:2016 is intended for:
- Aerospace OEMs and suppliers specifying or procuring MJ‑thread bolts in high‑strength, corrosion‑resisting steels.
- Fastener manufacturers who must meet aerospace procurement and inspection criteria.
- Quality, procurement and engineering teams responsible for component specification, inspection plans and supplier qualification.
- Certification and compliance auditors assessing fastener conformity to aerospace standards.
Related standards (referenced)
Keywords: ISO 8168:2016, aerospace bolts, MJ threads, heat and corrosion resisting steel, strength class 1 100 MPa, fastener procurement, bolt quality assurance, aerospace fasteners.