Aluminum 3103

Aluminum 3103 is a corrosion-resistant, moderately strong alloy ideal for CNC machining of components in HVAC, construction, and food processing industries where formability, durability, and surface finish are crucial.

Introduction to Aluminum 3103

Aluminum 3103 is a non-heat-treatable aluminum-manganese alloy known for its excellent corrosion resistance, moderate strength, and good formability. As part of the 3xxx series, it is often used in architectural panels, food-grade containers, and chemical processing systems where long-term resistance to atmospheric or chemical corrosion is required.

Thanks to its easy forming and clean machinability, Aluminum 3103 is frequently selected for CNC machining of panels, brackets, housings, and piping components in the construction, food, and HVAC industries.

Chemical, Physical, and Mechanical Properties of Aluminum 3103

Chemical Composition (Typical)

Element	Composition Range (wt.%)	Key Role
Aluminum (Al)	Balance	Base metal for lightweight, corrosion-resistant applications
Manganese (Mn)	0.9–1.5	Increases strength and improves corrosion resistance
Iron (Fe)	≤0.70	Residual element
Silicon (Si)	≤0.60	Residual element
Copper (Cu)	≤0.10	Residual element
Zinc (Zn)	≤0.10	Residual element
Others	≤0.15 (total)	Trace elements

Physical Properties

Property	Value (Typical)	Test Standard/Condition
Density	2.73 g/cm³	ASTM B311
Melting Point	635–655°C	ASTM E299
Thermal Conductivity	160 W/m·K at 25°C	ASTM E1952
Electrical Conductivity	38% IACS at 20°C	ASTM B193
Coefficient of Expansion	23.6 µm/m·°C	ASTM E228
Specific Heat Capacity	900 J/kg·K	ASTM E1269
Elastic Modulus	70 GPa	ASTM E111

Mechanical Properties (H14 Temper)

Property	Value (Typical)	Test Standard
Tensile Strength	180–200 MPa	ASTM E8/E8M
Yield Strength (0.2%)	160 MPa	ASTM E8/E8M
Elongation	≥10%	ASTM E8/E8M
Hardness	50–60 HB	ASTM E10
Fatigue Strength	80 MPa	ASTM E466
Impact Resistance	High	ASTM E23

Key Characteristics of Aluminum 3103

Excellent Corrosion Resistance: Performs exceptionally in atmospheric, industrial, and mildly chemical environments, making it ideal for piping, ducting, and cladding in HVAC and food facilities.

Moderate Strength with Good Workability: Offers higher strength than pure aluminum (like 1050) without compromising on formability—suitable for CNC machined parts with both structural and aesthetic requirements.

Superior Weldability: Supports TIG/MIG and resistance welding with minimal cracking. It is ideal for fabrications that require post-weld dimensional accuracy.

Non-Heat Treatable Alloy: Strengthening is achieved through cold working to tempers like H14, H16, or H18. Properties remain stable during thermal cycling.

Environmentally Friendly: Fully recyclable with minimal performance loss, widely adopted in sustainable design and green manufacturing initiatives.

CNC Machining Challenges and Solutions for Aluminum 3103

Machining Challenges

Soft Surface: Prone to scratching or galling if not handled and clamped properly.
Built-Up Edge (BUE): Material adhesion may reduce cutting-edge sharpness and surface finish.
Moderate Thermal Conductivity: This may require coolant optimization to maintain tight tolerances.

Optimized Machining Strategies

Tool Selection

Parameter	Recommendation	Rationale
Tool Material	Uncoated carbide or TiN-coated tools	Minimizes sticking and maintains tool sharpness
Geometry	Large rake angle, polished edges	Facilitates clean chip formation
Cutting Speed	200–400 m/min	Balances surface finish and productivity
Feed Rate	0.10–0.25 mm/rev	Supports fine tolerances and smooth edges
Coolant	Dry or mist coolant	Reduces friction without affecting surface finish

Aluminum 3103 Cutting Parameters (ISO 513 Compliance)

Operation	Speed (m/min)	Feed (mm/rev)	Depth of Cut (mm)	Coolant Pressure (bar)
Roughing	200–300	0.15–0.25	2.0–4.0	Dry or mist
Finishing	300–400	0.05–0.10	0.2–1.0	Mist or light flood

Surface Treatment for Aluminum 3103 CNC Parts

Anodizing: Accepts Type II and hard coat anodizing; ideal for improving the surface hardness and corrosion resistance. Coating thickness 5–25 µm typical.
Powder Coating: Provides 60–100 µm thick finishes with strong adhesion and UV resistance for architectural and consumer parts.
Electropolishing: Enhances Ra down to ≤0.2 µm for cleanroom and aesthetic finishes.
Passivation: Used to remove contaminants and improve post-machining corrosion performance.
Brushing: Produces satin finishes of Ra 0.8–1.6 µm on panels, covers, and consumer interfaces.
Alodine Coating: Enhances conductivity and corrosion resistance for aerospace and electronics housings.
UV Coating: Transparent film (5–15 µm) offers additional environmental protection for visible or branded parts.
Lacquer Coating: Used for clear, glossy protection in signage and architectural panels.