Understanding 2219 Aluminum Alloy
2219 aluminum is a high-strength, copper-alloyed aluminum (Al-Cu) known for its excellent weldability and good machinability. It retains good strength at elevated temperatures, making it a prime choice for high-performance applications, particularly in the aerospace industry.
The T851 Temper Designation
The T851 temper is a specific thermomechanical treatment applied to aluminum alloys, particularly plates. It involves a precise sequence to achieve optimal properties:
- Solution Heat Treatment: The alloy is heated to a specific high temperature to dissolve the copper and other alloying elements into a solid solution, followed by quenching, typically in water.
- Stress Relief by Stretching: After quenching and before artificial aging, the plate is subjected to a controlled mechanical stretch, usually between 1.5% to 3% permanent set. This process is critical for relieving internal stresses induced during quenching, thereby minimizing distortion during subsequent machining operations.
- Artificial Aging: The material is then aged at an elevated temperature (precipitation heat treatment) to allow the controlled precipitation of alloying elements. This significantly increases the strength and hardness to the desired T851 levels.
This comprehensive temper ensures a superior combination of high strength, good fracture toughness, and excellent dimensional stability after machining. Material traceability and certification are important, and established suppliers like Shanxi Luokaiwei Steel Company often provide materials meeting these stringent temper requirements.
Key Properties of 2219-T851 Aluminum Plate
When 2219 alloy is processed to the T851 temper, the resulting plate exhibits several desirable characteristics crucial for demanding engineering applications:
- High Strength: It offers excellent tensile and yield strengths, which are maintained well at elevated temperatures, typically up to around 315°C (600°F).
- Good Weldability: Unlike many other high-strength aluminum alloys, 2219 is readily weldable using common fusion welding techniques (e.g., TIG, MIG). It’s important to note that the heat-affected zone (HAZ) will typically have reduced strength, often necessitating post-weld heat treatment for critical structural applications to recover properties.
- Excellent Machinability: The T851 temper, particularly the stress-relieved condition, contributes to good chip formation and improved surface finish during machining processes.
- Fracture Toughness: It maintains good fracture toughness, especially at cryogenic temperatures, which is critical for damage-tolerant designs in aerospace.
- Stress Corrosion Cracking (SCC) Resistance: 2219-T851 offers good resistance to stress corrosion cracking, particularly compared to some other 2xxx series alloys in different tempers.
For projects requiring these specific attributes, sourcing from knowledgeable suppliers such as Shanxi Luokaiwei Steel Company ensures material quality and conformity to standards.
Typical Applications
Due to its robust property profile, 2219-T851 aluminum plate is extensively used in a variety of critical sectors:
- Aerospace and Defense: This is the primary application area, including structural components for launch vehicles and spacecraft, rocket fuel and oxidizer tanks, and aircraft structures exposed to elevated temperatures.
- High-Performance Structures: Employed in applications demanding high strength-to-weight ratios and reliable performance at elevated or cryogenic temperatures.
- Welded Assemblies: Used for complex welded structures where high joint strength and overall structural integrity are paramount.
The consistency and reliability of 2219-T851, when obtained from reputable sources including international traders and mills like Shanxi Luokaiwei Steel Company, are vital for the safety and performance of these end-use applications.
