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6061 aluminum is one of the most versatile and widely used aluminum alloys in the world. Known for its excellent strength-to-weight ratio, good corrosion resistance, weldability, and machinability, it's a popular choice across diverse industries, from structural components and automotive parts to marine fittings and general fabrication. 6061 aluminum round bar is a common form of this alloy, prized for its ease of machining into various shapes and components.
When purchasing 6061 aluminum round bar, understanding the available sizes is crucial for proper material selection and project planning. This guide outlines the typical range of diameters and lengths, as well as common considerations.
1. Standard Diameter Ranges
6061 aluminum round bar is readily available in a vast array of diameters to suit nearly any application. These are generally measured in inches (for North American markets) or millimeters (for metric markets).
1.1 Imperial Diameters (Inches)
In imperial measurements, round bar diameters typically range from very small to quite large.
- Small Diameters: Commonly start at 0.125 inches (1/8") and go up incrementally.
- Common Increments:
- Fractional: 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 5/8", 3/4", 7/8", 1"
- Further Increments: 1.125", 1.25", 1.375", 1.5", 1.625", 1.75", 1.875", 2"
- Medium Diameters: Continue upward in increments of 1/4" or 1/2" (e.g., 2.25", 2.5", 2.75", 3", 3.5", 4", 4.5", 5").
- Large Diameters: Available up to 12 inches or even larger from specialized suppliers, often in 1" or 2" increments (e.g., 6", 7", 8", 10", 12").
It's important to note that while many specific fractional and decimal sizes exist, common "stock" sizes are often preferred for availability and cost-efficiency.
1.2 Metric Diameters (Millimeters)
For metric specifications, diameters are typically expressed in millimeters.
- Small Diameters: Often start at 3 mm or 5 mm.
- Common Increments: 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm.
- Medium to Large Diameters: Continue upward in increments of 5 mm, 10 mm, or 20 mm (e.g., 60 mm, 70 mm, 80 mm, 100 mm, 120 mm, 150 mm).
- Largest Sizes: Can go up to 300 mm or more, depending on the supplier and manufacturing capabilities.
2. Standard Lengths
Just like diameters, 6061 aluminum round bar is sold in standard lengths, which can often be custom cut to specific requirements.
2.1 Standard Stock Lengths
- North America: Common stock lengths are 12 feet (144 inches) and 20 feet (240 inches).
- Metric Regions: Standard lengths are typically 3 meters (3000 mm), 4 meters (4000 mm), and 6 meters (6000 mm).
- Smaller Lengths: Many suppliers also offer "drops" or shorter standard lengths like 6 feet (72 inches) or 2 feet (24 inches) for smaller projects, or they will provide custom cutting services.
3. Temper
While not a size, the temper of 6061 aluminum round bar significantly affects its mechanical properties and thus its suitability for different applications. The most common tempers available are:
- 6061-T6: This is the most prevalent temper, offering excellent strength, hardness, and machinability. It has been solution heat-treated and artificially aged.
- 6061-T651: Similar to T6, but with a specific stress-relief stretching process applied after heat treatment, which minimizes distortion during machining. This is particularly relevant for larger diameter bars.
- 6061-O: Annealed condition, offering maximum ductility and formability, but with significantly lower strength. Less common for round bar but available.
4. Tolerances
It's crucial to be aware of manufacturing tolerances, especially for precision applications. Rolled or extruded round bars will have a specified diameter tolerance (e.g., +/- 0.005 inches), which can vary with diameter. For very tight tolerances, precision ground or drawn bars might be required, though 6061 round bar is typically an extruded product.
5. Where to Purchase
6061 aluminum round bar can be sourced from:
- Metal Supply Houses: Large distributors specializing in various metals.
- Online Metal Retailers: Many websites offer a wide range of sizes and often provide custom cutting services.
- Local Fabricators/Machine Shops: May stock common sizes or be able to order for you.
Conclusion
The extensive range of 6061 aluminum round bar sizes ensures that this versatile alloy can be adapted to countless applications. From tiny pins and shafts to large structural supports, understanding the available diameters, lengths, and tempers is key to selecting the right material for your next project. Always confirm specific dimensions and tolerances with your supplier, especially for critical applications.
