Cs-Flux: Ushering in a new era of high-magnesium aluminum alloy brazing

As the aluminum alloy brazing industry continues to pursue thinner tubes and fins as well as higher heat transfer performance, the development of high-strength aluminum alloys has become a mainstream trend, which directly drives the growing demand for higher magnesium (Mg) content. Nevertheless, the performance limitations of traditional potassium fluoroaluminate brazing fluxes have long made the brazing of high-magnesium aluminum alloys a major industry bottleneck. Zhejiang Xinrui Brazing Technology Co., Ltd. has launched Cs-Flux aluminum brazing flux to address this challenge.

Thanks to its excellent strength-to-weight ratio, high-magnesium aluminum alloy has become an indispensable core material in new energy vehicles and refrigeration & air conditioning industries.

In the thermal management systems of new energy vehicles, high-magnesium aluminum alloys are widely used in core components such as radiators, condensers, evaporators, intercoolers and battery cooling plates. The battery cooling plates are closely attached to power batteries. High-strength aluminum alloys are adopted to realize lightweight design and precise temperature control, so as to ensure battery safety and extend service life. According to industry forecasts, the global market size of electric vehicle thermal management solutions is expected to reach 80.87 billion US dollars by 2032, with a compound annual growth rate of 14.6% from 2026 to 2032. (Source: Global Info Research (GIR), Global Research Report on Thermal Management for Electric and Hybrid Vehicles – Overall Market Size, Major Enterprises, Regions, Products and Application Segments, released in March 2026.) Meanwhile, as one of the lightest structural metals, magnesium alloys see rapidly growing application in automobiles. The average usage of magnesium alloys per vehicle is projected to reach 45 kilograms by 2030. Aluminum and magnesium alloys have become two ideal materials for automotive lightweighting.

High-magnesium aluminum alloys also serve as essential materials in refrigeration and air conditioning equipment. Featuring high thermal conductivity and uniform heat transfer, they effectively improve the operating efficiency of evaporators and condensers, and reduce the load and energy consumption of compressors. In addition, the material maintains good toughness without low-temperature brittleness at an ultra-low temperature of -40℃. With a density of only 2.68 g/cm³, it is roughly two-thirds lighter than steel, which can greatly cut down the overall weight of refrigeration equipment.

However, both application scenarios impose higher requirements on the brazing performance of aluminum alloys. These high-strength aluminum alloys require elevated magnesium content to guarantee performance, and the drawbacks of traditional brazing fluxes have become a critical technical bottleneck restricting industrial development.

Traditional potassium fluoroaluminate brazing fluxes face great difficulties when brazing aluminum alloys with magnesium content over 0.3%, and are barely applicable when the magnesium content exceeds 0.5%. This severely limits the performance upgrading of heat exchangers and other related products.

As an innovative composite flux composed of potassium fluoroaluminate and Cs-Al-F compounds, Cs-Flux retains core advantages including non-corrosiveness and excellent applicability for aluminum-to-aluminum brazing, while achieving a groundbreaking breakthrough: its tolerance to magnesium in base metals is significantly enhanced. It can reliably braze aluminum alloys with magnesium content up to 0.6% and even 0.8%, removing the main obstacles for the large-scale application of high-strength aluminum alloys in new energy vehicles and refrigeration & air conditioning sectors.

More importantly, Cs-Flux delivers outstanding brazing quality while enabling lower consumption per unit. It helps enterprises cut procurement costs and material waste, reduces flux residue, and improves the cleanliness and reliability of finished products.

With high tolerance to high-magnesium aluminum alloys, lower consumption and cost advantages, as well as superior brazed joint quality, Cs-Flux is an ideal solution for the new energy vehicle and refrigeration & air conditioning industries to break design constraints and strengthen product competitiveness. Zhejiang Xinrui Brazing Technology Co., Ltd. always takes technological innovation as its core driving force. The launch of Cs-Flux is another solid effort to meet the industry’s demands for lightweight design and high-performance brazing.