Overview
ISO 5857:2008 - "Aerospace - Bolts, with MJ threads, made of alloy steel, strength class 1 250 MPa - Procurement specification" defines the procurement, inspection and quality requirements for aerospace bolts with MJ threads manufactured from alloy steel and rated to strength class 1 250 MPa. It is a procurement specification meant to be invoked whenever referenced in a definition document (e.g., drawing or contract). The standard focuses on characteristics, manufacturing controls and quality assurance to ensure safe, repeatable performance in aerospace applications.
Key topics and technical requirements
- Scope and applicability: Applies to MJ-thread bolts used in aerospace construction; applies when referenced in a definition document.
- Material and strength: Bolts of alloy steel, strength class 1250 MPa; material conformity is verified per the definition document and material standards.
- Dimensions and threads: Dimensional and thread limits follow the definition document and related MJ thread standards; threads must be formed by single rolling after full heat treatment.
- Manufacturing controls:
- Forging (hot or cold) prior to heat treatment with uniform temperature control for hot forging.
- Heat treatment rules (limited number of cycles) and stress-relieving after grinding but before thread/fillet rolling.
- Fillet cold-rolling between head and shank to remove machining marks and produce specified cold work (visual and dimensional checks).
- Surface roughness and coatings per the definition document and ISO surface texture methods.
- Mechanical tests: Tensile strength and double-shear strength requirements (referenced test methods such as ISO 7961 and ISO 6892); test temperature is ambient unless otherwise stated.
- Quality assurance and inspection:
- Qualification inspection (e.g., 25 bolts by simple random sampling) and production acceptance inspections per lot.
- Sampling plans and acceptance criteria (AQL, LQ) consistent with ISO 2859-1.
- Option to use Statistical Process Control (SPC) in lieu of final sampling if validated and approved.
- Quality records retention for a minimum of 10 years.
Practical applications and users
ISO 5857:2008 is used by:
- Aerospace fastener manufacturers for production and process control.
- OEMs, suppliers and procurement teams specifying bolt requirements on drawings and contracts.
- Quality, inspection and certification authorities responsible for qualification and lot acceptance.
- Design and structural engineers who require verified mechanical performance data for fastening systems.
- Maintenance/repair organizations sourcing replacement fasteners to meet aerospace traceability and safety requirements.
Keywords: ISO 5857:2008, aerospace bolts, MJ threads, alloy steel bolts, strength class 1250 MPa, procurement specification, quality assurance, sampling plan, heat treatment, tensile strength, statistical process control (SPC).
Related standards
Normative references include: ISO 2859-1, ISO 4288, ISO 5855-2 (MJ threads limits), ISO 6507-1, ISO 6508-1, ISO 6892, ISO 7961, ISO 7966, ISO 7870-1, ISO 8258 and ISO/TR 13425.
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