Application Case of Araldite AW146/HV957 Epoxy Structural Adhesive in Rail Transit & Honeycomb Panel Bonding

Many domestic rail transit equipment manufacturers need to bond and assemble aluminum honeycomb sandwich panels for side panels, roof panels and floor panels of subways, intercity trains and passenger trains. The bonded substrates include aluminum alloy sheets, PVC foams and PET foams. During operation, the vehicle is constantly subjected to vibration, dynamic load and temperature fluctuation. The bonded structure is required to have long-term weather resistance and anti-aging performance. Traditional adhesives are prone to debonding, cracking and strength degradation, failing to meet the service life requirement of more than 10 years for rail vehicles.

• Universal bonding performance: It can firmly bond dissimilar materials such as aluminum alloy, PVC and PET foam simultaneously, simplifying the production process without using multiple types of adhesives.
• Resistance to dynamic load and vibration: The tough glue layer effectively offsets continuous vibration and impact generated during train operation, preventing fatigue failure of the adhesive.
• Temperature resistance and anti-aging performance: The cured adhesive maintains stable mechanical properties within the temperature range from -60°C to 100°C. Its lap shear strength barely decreases after damp heat and tropical weathering tests, adapting to alternating high and low temperature inside carriages.
• Process adaptability: It cures completely at room temperature without high-temperature baking, so the foam core materials will not be damaged. The long pot life supports multi-station assembly on production lines.

1. Surface pretreatment: Remove oil stains and dust on aluminum alloy surfaces thoroughly with acetone. Conduct sand blasting to improve surface roughness, and perform secondary degreasing after sand blasting to ensure clean and dry bonding surfaces. Low-quality cleaning agents such as gasoline and paint thinners are prohibited.
2. Glue mixing & application: Mix the resin and hardener strictly at the weight ratio of 100:80 and stir until uniform color. Apply the mixed adhesive evenly on bonding surfaces with a scraper, and control the glue line thickness between 0.05 mm and 0.10 mm.
3. Assembly & curing: Assemble workpieces and apply uniform pressure immediately after gluing. At 23°C, the adhesive reaches the minimum usable shear strength in 7 hours, and the lap shear strength exceeds 10 N/mm² in 10 hours. Curing at 40°C for 16 hours can rapidly achieve standard mechanical properties, matching the turnover rhythm of production lines.

After the implementation of this solution, the lap shear strength of bonded sandwich panels for carriages remains stable. No debonding or warping occurs during long-term road tests, vibration tests and temperature cycling tests. The adhesive resists erosion from gasoline, lubricating oil and clean water, performing well in humid environment and daily cleaning of carriages. Up to now, this bonding solution has been steadily applied to multiple urban rail trains, with production efficiency and service life fully meeting design standards.

Aluminum honeycomb composite panels and galvanized steel composite panels are widely used in high-grade curtain walls and interior decoration projects. Mass bonding and forming are required for these panels. The applied adhesive needs high bonding strength, excellent outdoor weather resistance and anti-yellowing performance, and it shall be suitable for both factory prefabrication and on-site construction.

• Araldite AW146/HV957 provides outstanding bonding performance for metal substrates including aluminum alloy, stainless steel, galvanized steel, copper and brass. After sand blasting treatment, the metal lap shear strength reaches a high level.
• The cured adhesive resists immersion in water, xylene, lubricating oil and 10% dilute acetic acid. The bonding strength has slight attenuation after being soaked in normal temperature water and 60°C hot water for 90 days. It shows excellent anti-aging performance after tropical weathering tests, and no obvious failure occurs during long-term outdoor service, which is ideal for building curtain walls.
• The sealed product has a shelf life of up to 6 years at room temperature, reducing inventory cost for building material manufacturers. The paste adhesive has low sagging resistance, so it will not flow down during construction on vertical and top surfaces. Uniform glue lines can be guaranteed whether using automatic gluing equipment in factories or manual operation on construction sites, effectively reducing defective products.