oSIST prEN 3542:2022

Overview

The oSIST prEN 3542:2022 standard specifies requirements for aerospace-grade inserts featuring self-locking, helical coil screw threads with a tanged insertion drive. These inserts are manufactured from the heat-resistant nickel base alloy NI-PH2801 (Inconel X750), known for its superior mechanical properties at elevated temperatures. Designed primarily for aerospace applications, these inserts support thread locking and durability under demanding conditions, with a maximum test temperature rating of 550 °C.

Produced and maintained by CEN through the Aerospace and Defence Industries Association of Europe (ASD-STAN), oSIST prEN 3542:2022 updates and supersedes EN 3542:2018, reflecting the latest technical advancements and requirements in aerospace fastening technology.

Key Topics

• Insert Characteristics: The standard details configuration, dimensions, tolerances, and mass for inserts with MJ screw threads, ensuring consistent shape and performance.
• Material Specification: Inserts must be made from NI-PH2801, a nickel-chromium-based heat-resistant alloy compliant with EN 3018, guaranteeing excellent high-temperature resistance and mechanical strength.
• Self-locking Feature: The helical coil design includes an out-of-round zone to achieve self-locking without the use of additional locking elements, enhancing assembly reliability.
• Tanged Insertion Drive: Inserts feature a tang as part of the installation drive, facilitating secure placement and ease of installation.
• Marking and Designation: Compliance with EN 2424 for aerospace product marking ensures traceability and identification, using styles G and optionally F.
• Technical Specifications: The inserts conform to EN 2943 for technical requirements and EN 3044 for installation hole design.
• Quality Management: Manufacturers must operate under aerospace-approved quality management systems (e.g., EN 9100) and document qualification procedures as per EN 9133 or equivalent.

Applications

The oSIST prEN 3542:2022 standard applies to inserts used in critical aerospace components where high strength, heat resistance, and secure thread locking are essential. Typical applications include:

• Engine and airframe assemblies requiring maintenance-friendly yet robust threaded connections.
• High-temperature zones within aerospace components exposed to temperatures up to 550 °C.
• Structures where vibration and thermal cycling require self-locking threads to prevent loosening.
• Aerospace manufacturing and repair processes demanding standardized, certified fastening inserts.
• Components requiring heat-resistant nickel alloy inserts for enhanced durability and reliability.

By adhering to oSIST prEN 3542:2022, aerospace manufacturers and suppliers can ensure consistent quality and performance of critical fastening elements that meet rigorous safety and performance standards.

Related Standards

oSIST prEN 3542:2022 references and aligns with several key aerospace standards to ensure comprehensive application and conformity:

• EN 3018 – Defines the chemical and mechanical characteristics of the NI-PH2801 alloy used in insert manufacturing.
• EN 2943 – Technical specifications for inserts with MJ and M screw threads, critical for ensuring insert compatibility and function.
• EN 3044 – Provides guidelines for designing installation holes for self-locking, helical coil inserts.
• EN 2424 – Specifies aerospace marking standards for product traceability and compliance.
• EN 9100 – Aerospace quality management system requirements to ensure production reliability.
• ISO 5855-2 – Dimensioning limits for MJ threads, aiding in specification consistency for bolts and nuts used with these inserts.
• EN 9133 – Procedures for aerospace standard product qualification testing.

Summary

oSIST prEN 3542:2022 establishes a rigorous framework for the design, production, marking, and quality assurance of self-locking, helical coil aerospace inserts made from Inconel X750. This standard is essential for aerospace manufacturers seeking proven fastening solutions that withstand high temperatures and meet strict quality and safety requirements. Implementing oSIST prEN 3542:2022 supports reliability in critical aerospace assemblies, aligning with international best practices and ensuring compatibility across the aerospace supply chain.