Aluminum-based solder 4343

Classification: 4343

International Designations:

AA 4343 (Aluminum Association standard, USA)
ISO 4343 (AlSi7.5) (International Organization for Standardization)
Chinese Standard: GB4A13 (LT13)
Other National Standards:
- JIS A4343 (Japanese Industrial Standard)
- UNS A94343 (Unified Numbering System, USA)

Product Features:

Low Melting Point & High Fluidity
- Melting point: 577-582°C, narrow solidification range, excellent fluidity for filling complex joints, reducing porosity and crack defects.
- Higher silicon content (6.8%-8.2%) compared to 4043 aluminum alloy (Si 4.5%-6.0%), further enhancing feeding capacity and suppressing weld cracks.
Corrosion Resistance & High-Temperature Stability
- Aluminum-silicon alloy matrix resists oxidation and seawater corrosion, suitable for marine engineering and chemical equipment.
- Softening temperature up to 900°C under high temperatures, maintaining stable mechanical properties.
Process Adaptability
- Processable into sheets, welding wire, powder, etc., compatible with brazing, induction welding, laser sintering, and other techniques.
- Commonly used as a cladding layer for composite brazing sheets (e.g., LQ2 brazing alloy sheets) with cladding thickness of 0.07-0.16 mm.
Welding Compatibility
- Suitable for furnace brazing and flame brazing; requires flux (e.g., QJ206, QJ201) to optimize wettability and joint strength.

Applications:

Aerospace & Defense
- Manufacturing of aircraft engine turbine components, structural components of Shenzhou spacecraft, and large aircraft composite brazing sheets, withstanding high-temperature and high-pressure environments.
Automotive & Refrigeration Industry
- Brazing for automotive radiators and HVAC pipelines to ensure sealing and thermal efficiency; precision joining of refrigeration compressor parts to reduce leakage risks.
Electronics & Precision Instruments
- Heat sink substrate welding for high-power electronic components (e.g., IGBT modules), improving thermal management.
- Brazing for precision optical instrument brackets and aerospace fixtures, balancing lightweight design and strength.
Energy & Chemical Equipment
- High-temperature brazing for nuclear power plant cooling pipelines and chemical reactors, resisting corrosive media and thermal cycling stresses.
Composite Brazing Sheet Manufacturing
- Used as cladding material for LQ2 brazing sheets (base material: 3A21 aluminum alloy), widely applied in composite structure joining for ships, power equipment, etc.