EN 3542:2018

Overview

EN 3542:2018 is a European standard developed by CEN specifying the characteristics of self-locking helical coil screw thread inserts made from heat-resistant nickel base alloy NI-PH2801, commonly known as Inconel X750. These inserts are designed primarily for aerospace applications, where high-performance and resistance to extreme temperatures are critical. The inserts conform to MJ screw thread dimensions and include tanged insertion drive features for secure installation. The standard ensures reliability in demanding environments with a maximum test temperature of 550 °C.

Key Topics

• Material Specification
  EN 3542:2018 mandates the use of NI-PH2801 (Inconel X750), a nickel-based alloy renowned for its high temperature resistance and mechanical strength, meeting aerospace industry requirements. The material is cold-drawn and identified by a distinct yellow color without chlorine-based constituents.

• Thread Configuration and Dimensions
  The document details the insert design, including dimensions, tolerances, masses, number of coils, and locking features. It specifies thread sizes according to MJ standards (e.g., MJ4×0.7, MJ5×0.8), with precise measurements to ensure compatibility and performance in aerospace assemblies.

• Self-Locking Features
  The inserts utilize out-of-round coil forms and tangs that provide self-locking capabilities, preventing loosening under vibration or thermal cycling typical in aerospace services.

• Installation and Marking
  Installation procedures refer to related standards EN 2945 and EN 3044, ensuring proper fitting and function in aerospace components. The inserts are marked as per EN 2424 to guarantee traceability and compliance.

• Test Conditions
  Inserts must withstand tests at temperatures up to 550 °C, confirming their suitability for high-temperature aerospace applications.

Applications

EN 3542:2018 screw thread inserts are particularly designed for aerospace industry use, where:

• High temperature resistance is required, such as in turbine engines, airframe components, and avionics housings.
• Vibration and mechanical stress resistance are critical to maintaining secure fastening over operational lifetimes.
• Lightweight and corrosion-resistant fastening solutions enhance performance and extend component life.
• Aerospace manufacturers and suppliers integrate these inserts in assemblies requiring durable, high-performance screw thread repairs or reinforcements.
• Maintenance and overhaul operations utilize these inserts for thread repair in engines and structural aerospace parts.

Related Standards

EN 3542:2018 references several key aerospace and thread insert standards that support comprehensive design, application, and quality assurance including:

• EN 2943: Technical specifications for self-locking helical coil inserts.
• EN 2945: Assembly and installation procedures for screw thread inserts.
• EN 3018: Specification for heat-resisting alloy NI-PH2801 wire used in insert manufacturing.
• EN 3044: Design standard for installation holes tailored for self-locking helical coil inserts.
• EN 2424: Marking requirements for aerospace products to ensure identification and traceability.
• ISO 5855-2: Defines limit dimensions for MJ threads used in bolts and nuts, ensuring thread conformity.

Summary

EN 3542:2018 defines the requirements for self-locking, helical coil screw thread inserts made from high-grade nickel base alloy NI-PH2801 (Inconel X750) for aerospace applications demanding exceptional heat resistance and mechanical reliability. Compliance with this standard ensures optimal performance in aerospace construction, maintenance, and repair environments, supporting safety, durability, and regulatory adherence. Employing EN 3542:2018 inserts facilitates secure fastening solutions able to withstand harsh aerospace operational conditions.