Aluminum Alloy Grades Guide: 1050 to 7075

Introduction

With dozens of aluminum alloy grades available across seven major series, selecting the right alloy for your application is one of the most important material decisions you'll make. Each series offers a distinct balance of strength, corrosion resistance, formability, weldability, and cost. This guide provides a systematic overview of the most common grades (1xxx through 7xxx) and practical selection criteria.

Understanding the 4-Digit System

The first digit identifies the primary alloying element:

Series	Primary Alloying Element	Key Characteristics
1xxx	≥ 99% Pure Aluminum	Excellent corrosion resistance, high electrical/thermal conductivity, low strength
2xxx	Copper	High strength, poor corrosion resistance, aerospace applications
3xxx	Manganese	Moderate strength, good workability, beverage cans, roofing
4xxx	Silicon	Low melting point, welding filler alloys, brazing sheet
5xxx	Magnesium	Good strength, excellent corrosion resistance, marine grade
6xxx	Magnesium + Silicon	Heat-treatable, good strength, extrudability, versatile
7xxx	Zinc	Highest strength, aerospace and defense, stress corrosion risk

Series Overview and Common Grades

1xxx Series (Pure Aluminum)

Minimum 99% aluminum content. Common grades: 1050, 1060, 1100

• Strengths: Outstanding corrosion resistance, high thermal and electrical conductivity (~62% IACS for 1350), excellent reflectivity
• Limitations: Low strength (tensile ~70-110 MPa in annealed condition)
• Applications: Electrical bus bars, heat exchangers, chemical equipment, decorative trim, nameplates
• Available tempers: O, H14, H18, H24

5xxx Series (Al-Mg — Marine Grade)

Common grades: 5052, 5083, 5086, 5754

• Strengths: Excellent corrosion resistance (especially in marine environments), good weldability, moderate-to-high strength
• Limitations: Not heat-treatable, strain hardening only. 5083 is one of the strongest non-heat-treatable alloys
• Applications: Boat hulls and superstructures, pressure vessels, cryogenic tanks, automotive panels, architectural roofing
• 5083 tensile strength: 270-350 MPa in H116/H321 temper

6xxx Series (Al-Mg-Si — The Workhorse)

Common grades: 6061, 6063, 6082

• Strengths: Heat-treatable, good strength-to-weight ratio, excellent extrudability, good corrosion resistance and weldability. The most versatile series
• Limitations: Lower strength than 2xxx or 7xxx series
• 6061-T6 tensile strength: ~310 MPa — the most commonly specified alloy for structural applications
• 6063: Preferred for architectural extrusions due to superior surface finish
• Applications: Structural framing, pipe and tubing, automotive components, bicycle frames, bridges, rail cars, furniture

7xxx Series (Al-Zn — Aerospace Grade)

Common grades: 7050, 7075, 7475

• Strengths: Highest strength aluminum alloys available. 7075-T6 tensile strength: ~570 MPa — approaching some steels
• Limitations: Lower corrosion resistance (requires cladding or coating), more difficult to weld, susceptible to stress corrosion cracking in certain tempers
• Applications: Aircraft structural components, aerospace tooling, rock climbing equipment, automotive racing, defense equipment
• 7075 availability: Plate, sheet, bar, and tube in T6, T651, and T73 tempers

Understanding Tempers

The temper designation indicates how the alloy was processed:

Temper	Meaning	Typical Use
O	Annealed (softest)	Deep drawing, maximum formability
H14	Strain-hardened (quarter hard)	General sheet metal work, bending
H18	Strain-hardened (full hard)	Minimum formability, maximum strength from work hardening
T4	Solution heat-treated + natural aging	Good formability after heat treatment
T6	Solution heat-treated + artificial aging	Maximum strength for heat-treatable alloys
T651	T6 + stress relieved by stretching	Plate and bar — reduced distortion during machining

Selection Guide by Application

Application	Recommended Grade	Rationale
Marine / Boat building	5083 / 5086	Excellent seawater corrosion resistance
Structural / Framing	6061-T6 / 6082-T6	Good strength, weldability, extrudability
Aerospace structures	7075-T6 / 7050-T7451	Highest strength-to-weight ratio
Architectural extrusions	6063-T5 / T6	Superior surface finish, anodizing quality
Heat exchangers	1050 / 1100	High thermal conductivity, formability
Pressure vessels	5083 / 6061	Good weldability, certified properties
Automotive body panels	5052 / 5182 / 6016	Formability + strength after paint bake
Electrical components	1050 / 1350	High electrical conductivity

Conclusion

Selecting the right aluminum alloy requires balancing strength, corrosion resistance, formability, weldability, and cost. For most industrial and structural applications, 6061-T6 offers the best all-around performance. For marine environments, choose 5083. For maximum strength, 7075-T6 is the benchmark. Always specify the correct temper for your manufacturing process — a T6 temper may be too brittle for extensive forming, while an O temper may be too soft for structural use.