Definition of Aluminum 6061-T651 | 3.3211 | 65028 | AlMg1SiCu
Aluminum 6061-T651 | 3.3211 | 65028 | AlMg1SiCu is a strong and lightweight aluminum alloy made mainly with magnesium and silicon, with a small amount of copper. The T651 condition helps reduce internal stress, so the material stays more stable during machining. It also offers good corrosion resistance, machinability, and weldability. It is widely used for CNC parts, frames, brackets, fittings, automotive components, aerospace parts, and general industrial products.
Properties of Aluminum 6061-T651 | 3.3211 | 65028 | AlMg1SiCu
| Property | Value |
|---|---|
| Mechanical Properties | |
| Ultimate tensile strength | 290 – 330 MPa |
| Yield strength | 250 – 270 MPa |
| Elongation at break | 8 – 11 % |
| Physical Properties | |
| Corrosion resistance | High |
| Magnetism | Non-magnetic |
| Weldability | High |
| Thermal Properties | |
| Maximum service temperature | 170 °C |
| Thermal conductivity | 167 – 170 W/(m⋅°C) |
| Post Treatments | |
| Post-Processing | Annealing & Cold working |
| Anodizing compatibility | Suitable |
| Common Applications | |
| Automotive Industry | Aerospace Industry |
| Marine Industry | Construction Industry |
| Sporting Goods | |
Why Aluminum 6061-T651 | 3.3211 | 65028 | AlMg1SiCu Matters in CNC Workshops
- Good machinability: Aluminum 6061-T651 works well with CNC milling, turning, drilling, and other precision machining processes.
- Better dimensional stability: The T651 treatment reduces internal stress, helping parts keep their shape when larger amounts of material are removed.
- Good strength and low weight: It provides useful strength without adding the heavy weight of steel, making it suitable for many mechanical parts.
- Good corrosion resistance: Aluminum 6061-T651 performs well in many indoor, outdoor, automotive, marine, and industrial environments.
Surface Finishes for Aluminum 6061-T651 | 3.3211 | 65028 | AlMg1SiCu
As-Machined
The default finish from CNC machining plastic stock (Delrin, nylon, HDPE, ABS). Visible linear tool path scallop marks across machined surfaces with a matte plastic sheen. No secondary operation suitable for functional components, jigs, fixtures, and internal parts where cosmetic appearance is secondary to dimensional accuracy.
Flame Polished
Quick post-fabrication process that passes a controlled flame over acrylic (PMMA) cut edges, melting the surface micro-layer to produce a crystal-clear, glossy, transparent edge. Fast and cost-effective for acrylic sheet edges produces optical clarity on cut borders without the labor of hand polishing. Ideal for display cases, signage, and acrylic enclosures.
Vapor Polished
Post-fabrication chemical process that exposes transparent plastic parts (acrylic, PC, PETG) to solvent vapor, melting and smoothing the surface micro-layer to dramatically improve optical clarity and gloss. Removes machining lines and produces crystal-clear transparent parts — essential for prototype lenses, light guides, display windows, fluidic chambers, and medical components requiring optical transparency.
Painted
Post-fabrication spray painting in any custom color (matte, satin, gloss, metallic) followed by screen printing or pad printing for logos, labels, buttons, and graphics. Applied over a primed plastic surface for uniform color and adhesion. Allows custom fabricated plastic parts to match production aesthetics widely used for control panels, instrument faces, enclosures, and marketing/showcase components requiring exact brand color and graphic printing.
Sanded
Post-fabrication sanding with progressively finer grit sandpaper (typically 240–600 grit) produces a uniform low-gloss matte non-reflective surface. Hides machining marks, scratches, and surface inconsistencies while providing a soft tactile feel. Used for HDPE, UHMW, and nylon components where a durable, non-glare, fingerprint-resistant matte appearance is desired for industrial and functional parts.
Heat Formed
Thermoforming process that heats plastic sheet (acrylic, polycarbonate, ABS) to its glass transition temperature and bends it over a form tool to create precise angles and curved shapes. Produces clean, smooth bend radii with consistent surface finish no tool marks at the bend. Used for display stands, guards, enclosures, signage, and custom fabricated parts requiring 3D formed shapes from flat sheet stock.
