4047 Aluminum Brazing Sheet: The Performance Benchmark in High-Silicon Aluminum-Based Filler Metals

In the aluminum and aluminum alloy welding material system, the 4047 aluminum brazing sheet stands out as a core material for high-end welding applications such as heat exchanger manufacturing and precision component joining, thanks to its high silicon content and excellent brazing adaptability. Its unique combination of properties not only meets stringent process requirements but also drives welding technology advancements across multiple industries, making it an indispensable high-quality aluminum-based filler metal in the industrial sector.

I. High-Silicon-Dominated Chemical Composition: The Core Code of Performance

The exceptional performance of the 4047 aluminum brazing sheet stems from its precisely designed chemical composition, with high silicon content being its most notable feature. The sheet is based on aluminum (Al) as the remainder, with silicon (Si) content as high as 11.0%–13.0%, a high proportion that is key to achieving excellent fluidity and a low melting point. At the same time, the content of impurity elements is strictly controlled: iron (Fe) ≤0.8%, copper (Cu) ≤0.30%, manganese (Mn) ≤0.15%, magnesium (Mg) ≤0.05%, zinc (Zn) ≤0.10%, other single impurity elements ≤0.05%, and total impurities ≤0.15%. This high-silicon-centric composition system ensures process stability during welding while providing a foundation for the density and corrosion resistance of the weld seam.

II. Irreplaceable Performance Characteristics: Advantages for High-Demand Scenarios

(I) Exceptional Brazing Process Performance

As a typical high-silicon aluminum-silicon alloy filler metal, the 4047 aluminum brazing sheet demonstrates top-tier brazing adaptability. Its melting point is as low as 580–620°C, significantly lower than that of ordinary aluminum alloy base materials, enabling welding without excessive heat deformation of the base material. This makes it particularly suitable for joining thin-walled parts and precision structures. During welding, the molten pool exhibits excellent fluidity, fully filling complex gaps and narrow joints. When used with low-temperature aluminum brazing powder, it effectively reduces defects such as porosity and lack of fusion. Compared to medium-silicon filler metals like 4004, it solidifies more quickly, performing especially well in gas-shielded welding and Nocolok brazing processes. The resulting weld seam is smooth and dense, requiring minimal post-weld finishing.

(II) Balanced Mechanical and Corrosion Resistance Properties

The welded joints of the 4047 aluminum brazing sheet exhibit good mechanical stability. Although the high silicon content slightly reduces material plasticity, it is sufficient to meet the load requirements of components such as heat exchangers. The weld strength is highly compatible with commonly used core materials like 3003 and 3004. In terms of corrosion resistance, the weld structure formed by this sheet is uniform, capable of resisting erosion from coolants, air, and other media. When used with anti-corrosion cladding layers like 7072, it significantly extends the service life of aluminum components. Additionally, the welded joints offer excellent thermal conductivity, a critical feature in heat exchange equipment such as radiators and condensers, ensuring efficient heat transfer without obstruction from the weld seam.

III. Flexible and Diverse Specifications: Precision Adaptation to Production Needs

The 4047 aluminum brazing sheet is designed with specifications that fully consider the production differences across various industries, offering highly flexible options.

(I) Thickness Specifications: Comprehensive Coverage from Precision to Conventional

Standard thicknesses include 0.10mm, 0.15mm, 0.20mm, and 0.30mm. These thin specifications are particularly suitable for the cladding layer of heat exchanger composite foils, enabling precise brazing of multilayer composite materials. For the welding needs of large equipment, thicker specifications ranging from 0.50mm to 2.0mm are available to meet the requirements for multilayer welding of thick-walled aluminum parts. Some manufacturers support custom production within the range of 0.08mm to 3.0mm, adapting to various welding scenarios from microelectronics to industrial equipment.

(II) Width Specifications: Efficiency Assurance for Mass Production

Width specifications cover standard sizes such as 100mm, 150mm, 200mm, 300mm, and 600mm. Wide-width products can be directly used in the production of large composite panels, reducing the number of splices and improving production efficiency. For small component welding and repair scenarios, narrow-width slit products are available to minimize material waste. Manufacturers can provide continuous supply of custom widths based on customer coil processing needs, meeting the feeding requirements of automated welding production lines.

IV. Focus on Core Areas: Key Material for Heat Exchange and Composite Materials

(I) Automotive and Industrial Heat Exchanger Manufacturing

The 4047 aluminum brazing sheet is a core material for brazed heat exchangers, widely used in the production of automotive air conditioners, radiators, oil coolers, heaters, and other equipment. In these products, 4047 typically serves as the cladding alloy, combined with core materials like 3003 to form multilayer structures. After brazing, it achieves both efficient heat exchange and structural stability. The 4047 brazing sheet is also extensively used in the repair of traditional aluminum radiators, favored by the repair market for its low cost and reliable performance.

(II) Composite Materials and Precision Component Joining

In aluminum alloy composite material production, the 4047 aluminum brazing sheet serves as the cladding layer, combined with core materials through lamination and rolling to form 2–5 layer composite plates, strips, and foils. These composite materials are widely used in specialized heat exchange devices such as hand dryers and air separation equipment. Additionally, its precise welding performance makes it important for joining heat sinks in electronic devices and small precision aluminum components, enabling reliable connections in confined spaces without affecting component functionality.

V. Development Prospects Driven by Technological Upgrades

With the rapid development of automotive lightweighting and the new energy industry, the 4047 aluminum brazing sheet is facing new opportunities. Its future development will focus on three main directions: First, process optimization, using advanced technologies like vacuum melting to reduce impurity content, further enhancing weld purity and corrosion resistance to meet the higher demands of new energy vehicle coolant systems. Second, product iteration, developing derivative alloys with lower melting points and higher toughness to address the plasticity limitations of high-silicon materials and expand into high-end fields such as aerospace. Third, green production, adopting waste recycling and regeneration technologies to reduce production costs and carbon emissions while maintaining performance stability, aligning with global trends in low-carbon manufacturing. With its irreplaceable brazing advantages, the 4047 aluminum brazing sheet will continue to hold a core position in the advancement of heat exchange technology.