EN 3961:2001

Overview

EN 3961:2001 is a European standard that specifies the requirements for the aerospace-grade gold base alloy AU-B40001 used as filler metal for brazing in the form of rolled foil. Developed under the auspices of the European Committee for Standardization (CEN), this standard addresses critical criteria for material composition, production, mechanical properties, and quality assurance tailored to the high-performance and safety demands of aerospace applications. As part of the aerospace metallic materials series, EN 3961 ensures consistent quality and compatibility of brazing filler metals essential for joining components made from nickel base alloys and other high-strength materials.

Key Topics

• Gold Base Alloy AU-B40001
  Defines the chemical composition with key alloying elements such as nickel, aluminum, platinum, titanium, and zirconium, ensuring optimal mechanical and thermal properties for aerospace brazing operations.

• Filler Metal for Brazing
  Specifies the use of this alloy exclusively as filler metal to join aerospace components, focusing on its ability to create strong, reliable joints with high shear strength and resistance to thermal stresses.

• Rolled Foil Form
  Details manufacturing processes including cold rolling and cleaning to produce the filler metal as thin foil, enhancing ease of use and precise application control during brazing.

• Material and Mechanical Specifications
  Includes stringent requirements for chemical composition, melting methods, delivery conditions (as manufactured or annealed), thickness limits, proof stress, tensile strength, elongation, hardness, shear strength, and other mechanical characteristics critical to aerospace safety and reliability.

• Quality and Inspection
  Encompasses dimensional inspections, batch uniformity checks, thermal analyses (eutectic temperature at 950 °C), wettability (fusion test), and marking inspections, all performed according to related standards such as EN 3875 and EN 2043 to ensure conformity and traceability.

Applications

EN 3961:2001 gold base alloy brazing foil is predominantly utilized in joining nickel base alloys and other non-ferrous aerospace materials where:

• High joint strength and corrosion resistance are mandatory for structural integrity under extreme aerodynamic and environmental conditions.
• Thermal stability is essential, especially in high-temperature zones of engines, turbines, and airframe components.
• Precision brazing applications require thin filler material with controlled metallurgy for consistent bonding.
• Aerospace manufacturing and maintenance workflows demand standardized filler metals to streamline assembly, repair, and overhaul processes in compliance with industry regulations.

Using EN 3961 compliant filler metal foil guarantees superior brazed joint quality, reduces risk of component failure, and supports lifecycle durability of aerospace equipment.

Related Standards

EN 3961 refers to and harmonizes with the following key aerospace material standards for comprehensive compliance:

• EN 2043 – Metallic materials general requirements for semi-finished product qualification (excluding forgings and castings).
• EN 3875 – Technical specification for metallic filler metal for brazing, detailing chemical and mechanical characterization.
• EN 4258 – Overview of standardization organization and linkages between different EN aerospace material standards.
• EN 4500-6 – Rules for drafting and presenting material standards, specifically tailored for filler metals used in brazing.

Together, these standards create an integrated framework ensuring that filler metals like AU-B40001 meet exacting performance criteria demanded by aerospace industry applications, promoting both safety and efficiency in manufacturing and repair.

Keywords: EN 3961, aerospace standard, gold base alloy, AU-B40001, filler metal, brazing, rolled foil, nickel base alloys, aerospace materials, material specifications, quality assurance, thermal stability, mechanical properties, EN 3875, EN 2043, EN 4258.