Overview
ISO 9152:1998 - Aerospace - Bolts, with MJ threads, in titanium alloys, strength class 1 100 MPa - Procurement specification - is an ISO procurement and quality assurance standard that defines the characteristics, inspection, testing and supplier qualification requirements for MJ‑thread bolts made from titanium alloys for aerospace use. The standard is intended to be invoked by a definition document (drawing or specification) and complements related material and test standards referenced within.
Key topics and technical requirements
- Material & strength class: Bolts must be manufactured from the titanium alloy and strength class identified in the definition document; material compliance is verified by reference to the material standard.
- Manufacture and processing:
- Hot forging of bolt heads prior to heat treatment.
- Controlled heat treatment (blanks not heat‑treated more than twice).
- Threads formed by rolling after full heat treatment.
- Fillet between head and shank to be cold‑rolled after heat treatment and machining to remove machining marks; visual inspection at ×10–×20 magnification.
- Surface and coatings: Surface finish and coatings are to comply with the definition document and ISO 4288 surface‑texture rules; penetrant inspection per ISO 3452 where required.
- Mechanical tests:
- Tensile strength and double‑shear strength tests (see Tables referenced in the standard).
- Tension‑fatigue requirements: mean life ≥ 65 000 cycles; individual life ≥ 45 000 cycles and ≤ 130 000 cycles; test frequency ≤ 140 Hz; loads defined in the standard.
- Recess/driving feature torque test: driving feature must resist specified removal torque without cam‑out; test includes application of a defined end load (specified in the standard).
- Quality assurance and inspection:
- Manufacturer approval per ISO 9002 and retention of quality documentation for minimum 10 years.
- Qualification inspections (e.g., 25 bolts sampled by simple random sampling for each type/diameter).
- Production acceptance sampling plans referenced to ISO 2859‑1 and use of SPC methods (ISO/TR 13425, ISO 7966, ISO 7870, ISO 8258) where validated.
- Definitions and defect classification: Clear terms for production batch, inspection lot, critical/major/minor defects, and sampling plans.
Applications and users
- Who uses it: aerospace procurement engineers, fastener manufacturers and suppliers, quality assurance and certification authorities, design and structural engineers specifying fasteners for airframe assemblies.
- Practical use cases:
- Contractual procurement specification for titanium MJ‑thread bolts in aircraft and spacecraft structures.
- Supplier qualification and acceptance testing programs.
- Establishing inspection plans, control charts and SPC integration for production reliability.
Related standards
Keywords: ISO 9152:1998, aerospace bolts, MJ threads, titanium alloys, procurement specification, bolt qualification, tension fatigue, fastener quality control.