EN 3753:2010

Overview

EN 3753:2010 is a European standard developed by CEN that specifies the requirements for aerospace-grade self-locking anchor nuts. These nuts are characterized by a 60° corner design with a counterbore and are made from alloy steel. To enhance durability and corrosion resistance, the nuts are cadmium plated and lubricated with molybdenum disulfide (MoS2). They are classified for a tensile strength of 1100 MPa at ambient temperature and can withstand temperatures up to 235 °C without performance degradation.

This standard is essential for the aerospace industry, ensuring consistent quality and performance of fixed anchor nuts with self-locking features suitable for high-stress and high-temperature environments.

Key Features

• Self-locking mechanism: Achieved by forming the upper portion of the nut out-of-round, ensuring secure fastening without the need for additional locking components.
• Material and coating: Constructed from alloy steel with a cadmium plating for corrosion protection and MoS2 lubrication to reduce friction.
• Design: Features a 60° corner angle with a counterbore to fit aerospace bolt assemblies precisely.
• Classification: Rated at 1100 MPa tensile strength and temperature resistance up to 235 °C.
• Dimensional accuracy: Complies with aerospace tolerances for form, position, and thread dimensions according to ISO 8788 and ISO 5855-2.
• Surface treatment: Cadmium plating depth of at least 5 µm on contact surfaces, complying with EN 2133 and EN 2491 standards for coatings and lubrication.

Applications

EN 3753:2010 fixed anchor nuts are specifically designed for aerospace applications where reliability, safety, and performance under mechanical stress are critical. Typical applications include:

• Aircraft structural assembly requiring secure, vibration-resistant fastening solutions.
• Aerospace component manufacturing where temperature-resistant and lubricated locknuts prevent loosening.
• Maintenance and repair of aircraft where standardized nuts allow for consistent replacement parts.
• Use in environments with stringent corrosion and temperature resistance requirements.

By adhering to EN 3753:2010, manufacturers and engineers can ensure compatibility with aerospace-grade bolts and assembly procedures, contributing to the integrity and longevity of aerospace hardware.

Related Standards

This standard interfaces with several other aerospace and quality management standards to guarantee product performance and traceability:

• EN 2133: Cadmium plating of steels for aerospace applications.
• EN 2424: Marking requirements for aerospace products.
• EN 2491: Coating methods for molybdenum disulfide dry lubricants.
• EN 2542 & EN 2543: Material specifications for alloy steels used in prevailing torque nuts.
• ISO 5855-2 & ISO 5858: Aerospace thread and nut dimensional standards.
• ISO 8788: Tolerances of form and position for aerospace nuts.
• EN 9100 & EN 9133: Quality management systems and qualification procedures specific to aerospace standard parts.
• TR 3791: Technical report on materials for self-locking nuts and inserts suitable for temperatures up to 425 °C.

Practical Value

Compliance with EN 3753:2010 ensures aerospace anchor nuts:

• Maintain mechanical integrity under high loads and elevated temperatures.
• Prevent unwanted loosening through a reliable self-locking design.
• Offer corrosion resistance due to cadmium plating, extending service life in harsh environments.
• Meet stringent aerospace quality and safety requirements, enhancing overall aircraft reliability.
• Support efficient manufacturing and quality control processes with detailed specifications for dimensions, materials, and surface treatments.

Adopting this standard benefits aerospace manufacturers, suppliers, and maintenance organizations by providing a harmonized benchmark for fixed anchor nuts, fostering international interoperability and quality assurance in aerospace hardware components.