EN 3940:1998

Overview

EN 3940:1998 is a European standard developed by CEN that defines the requirements for the nickel base alloy NI-B46001 (NiCo20Si5B3) used as a filler metal in brazing applications, specifically in the aerospace industry. This standard details the specifications for the filler metal supplied in tape form, ensuring consistency, quality, and performance suitability for critical aerospace manufacturing processes. The material plays a crucial role in joining high-temperature resistant components where strong, reliable joints are mandatory.

Key Topics

• Material Composition: The standard covers the nickel base alloy NI-B46001 (NiCo20Si5B3), characterized by its nickel-cobalt-silicon-boron composition, optimized for superior brazing performance.
• Filler Metal Form: The alloy is supplied as tape, facilitating easy handling and precise application during brazing operations.
• Aerospace Application Requirements: EN 3940 specifies the chemical, mechanical, and physical properties necessary to meet stringent aerospace industry demands.
• Quality Controls: The standard sets benchmarks for material uniformity, alloy purity, and tape dimensions to ensure consistent brazing results.
• Terminology and Symbols: Clear definitions and standardized symbols ensure universal understanding and application across manufacturers and engineers.

Applications

EN 3940:1998 nickel base alloy filler metal tape is vital for aerospace component manufacturing, particularly where high-strength, heat-resistant brazed joints are required. Typical applications include:

• Turbine Engine Assembly: Joining nickel-based superalloy parts in gas turbines, where high temperature and corrosion resistance are essential.
• Aerospace Structural Components: Fabrication of critical frameworks that require precise brazed connections minimizing joint weaknesses.
• Heat Exchangers and Exhaust Systems: Ensuring durable joints in components exposed to thermal cycling and oxidative environments.
• Precision Repair and Maintenance: Use in refurbishing complex aerospace parts requiring metallurgically sound brazed repairs.

Utilizing standardized filler metals like NI-B46001 tape reduces the risk of brazing defects, improves joint integrity, and enhances overall aircraft safety and performance.

Related Standards

For comprehensive aerospace brazing process control and material compatibility, EN 3940:1998 is often referenced alongside:

• EN 12797 – Aerospace series: brazing filler metals – Properties and specifications for various alloy types.
• EN 13670 – Aerospace series: brazing procedures and qualification methods to ensure joints meet aerospace tolerances.
• AS9100 – Quality management systems for aerospace industry suppliers that emphasize compliance with material standards.
• ISO 17672 – Brazing – Filler metals – Classification and specifications, guiding global material standard harmonization.

These complementary standards help aerospace manufacturers maintain consistent brazing quality and adhere to international best practices.

Keywords: EN 3940:1998, nickel base alloy NI-B46001, filler metal for brazing, brazing tape, aerospace brazing standard, NiCo20Si5B3, aerospace manufacturing materials, high-temperature brazing alloy, CEN aerospace standards