The main difference between 3003 H18 and 1100 aluminum lies in their alloy composition, resulting in a direct trade-off between structural strength and workability. 3003 H18 is a manganese-alloyed aluminum that is fully work-hardened, offering significantly higher strength and surface hardness but almost zero ductility. In contrast, 1100 aluminum is a commercially pure aluminum that offers very low strength but delivers excellent formability, superior corrosion resistance, and high electrical and thermal conductivity.
When purchasing aluminum for an industrial project, confusing a pure aluminum grade with a work-hardened alloy will lead to immediate manufacturing failures. If you stamp 3003 H18 into a deep container, it will fracture. If you use 1100 aluminum for a structural panel requiring rigidity, it will deform under minimal pressure.
This technical guide compares the mechanical properties, processing limits, electrical conductivity, and specific industrial applications of 3003 H18 and 1100 aluminum to ensure you specify the exact material your production line requires.
3003 Aluminum Sheet vs 1100 Aluminum Coil
Before analyzing the temper differences, we must look at the base chemistry. The chemical composition dictates the fundamental capabilities of the metal.
What is 1100 Aluminum?
1100 aluminum belongs to the 1xxx series. It is defined as commercially pure aluminum, containing a minimum of 99.0% aluminum. Because it lacks significant strengthening alloying elements like copper, magnesium, or manganese, it is extremely soft. However, this high purity grants it the highest electrical conductivity, thermal conductivity, and corrosion resistance among standard aluminum grades.
What is 3003 Aluminum?
3003 aluminum belongs to the 3xxx series. Its primary alloying element is manganese (roughly 1.0% to 1.5%). This small addition of manganese fundamentally changes the metal, making it approximately 20% stronger than 1100 pure aluminum even in its baseline state. It is the most widely used general-purpose anti-rust aluminum alloy.
Both 1100 and 3003 share one critical trait: they are non-heat-treatable. Their strength cannot be increased by placing them in an aging furnace. Their strength is dictated entirely by mechanical cold rolling.
Understanding the H18 Temper in 3003 H18 Aluminum Plate
When comparing these two metals, it is crucial to understand that we are comparing a fully hardened alloy (3003 H18) against what is typically used as a highly formable pure metal (1100).
The H18 designation attached to 3003 means it has been fully strain-hardened at the rolling mill. It is cold-rolled to its maximum commercial reduction without any thermal annealing to relieve internal stress. This pushes the strength and hardness of the 3003 alloy to its absolute physical limit, but it completely destroys the material's ductility. It becomes highly rigid and brittle.
Are you trying to determine if your product design requires the high conductivity of pure 1100 aluminum or the rigid strength of 3003 H18? Selecting the wrong material will result in costly scrap rates. Contact our engineering team today for a free technical evaluation and request samples to test on your own factory equipment.
Core Differences Overview
The table below outlines the fundamental operational differences between commercially pure aluminum and a fully hardened manganese alloy.
| Property | 1100 Aluminum (Pure Al) | 3003 H18 Aluminum (Al-Mn) |
| Alloy Type | Commercially Pure (≥99.0%) | Manganese Alloyed |
| Overall Strength | Very Low | Medium-High (for non-heat-treatable) |
| Hardness Level | Very Low | High |
| Ductility | Excellent | Very Low |
| Electrical/Thermal Conductivity | Excellent | Moderate |
| Formability | Excellent (Deep drawing) | Poor (Brittle, limited to flat use) |
Mechanical Properties Comparison of 3003 H18 and 1100 Aluminum
To program CNC press brakes or stamping dies, engineers need exact physical parameters. The table below compares 3003 in its hardest state (H18) against 1100 in its typical, highly formable state (O temper).
| Mechanical Property | 1100 Aluminum (O Temper) | 3003 H18 Aluminum (Full Hard) |
| Tensile Strength | 70 – 110 MPa | 140 – 180 MPa |
| Yield Strength | 30 – 50 MPa | 120 – 150 MPa |
| Hardness (Brinell) | ~ 20 – 30 HB | ~ 40 – 55 HB |
| Elongation | Very High (> 25%) | Very Low (~ 1% - 4%) |
Data Analysis for Manufacturing:
The difference in Yield Strength is staggering. 3003 H18 requires four to five times more mechanical force to permanently deform than 1100 aluminum. However, 1100 aluminum has an elongation rate exceeding 25%, allowing it to stretch deeply into complex die cavities without tearing. 3003 H18, with an elongation near zero, will snap immediately if subjected to the same stretching force.
Can 1100 Aluminum Be Bent?
Fabrication behavior dictates where these materials can be used on the factory floor.
Processing 1100 Aluminum Sheet
1100 aluminum is the ultimate material for heavy forming. It can be bent, folded, spun, and deep-drawn with minimal tooling pressure. It exhibits virtually no springback, meaning it holds the exact shape of the die. It will not crack along sharp bend radii.
Processing 3003 H18 Aluminum Coil
3003 H18 cannot be formed. It is meant to remain flat. If you attempt a 90-degree fold on a press brake, the material will fracture along the bend line. It is suitable only for high-speed, shallow blanking where structural rigidity in a thin gauge is required.
Conductivity and Corrosion Resistance
These two properties are where 1100 pure aluminum outperforms almost all other aluminum alloys.
Electrical and Thermal Conductivity
Because 1100 aluminum is 99.0% pure, there are very few alloying elements to interfere with the flow of electrons or thermal energy. It offers excellent electrical and thermal conductivity. 3003 H18, due to the addition of manganese and its highly compressed grain structure, has significantly lower conductivity. If you are manufacturing heat sinks, radiators, or electrical busbars, 1100 is the mandatory choice.
Corrosion Resistance
Pure aluminum (1100) naturally forms a dense, uninterrupted aluminum oxide layer, giving it the best corrosion resistance among all aluminum grades, especially against chemical attacks. 3003 also has excellent corrosion resistance, but it is marginally lower than 1100 due to the alloyed manganese. Both are highly suitable for outdoor atmospheric exposure.
3003 H18 vs 1100 Aluminum
Understanding how these materials fail when misapplied is critical for procurement.
Case Study 1: The Transformer Winding Failure
An electrical equipment manufacturer attempted to substitute 1100 aluminum strips with 3003 H14 (a softer version of 3003) to increase the physical strength of their transformer windings. While the material wound successfully, the electrical resistance of the 3003 alloy caused the transformer to overheat and fail during standard load testing. The manganese addition interrupted the electrical flow. They immediately reverted to using 1100 aluminum coil. The pure aluminum provided the necessary electrical conductivity to keep the transformer operating within safe temperature limits.
Case Study 2: The Pharmaceutical Closure Problem
A packaging facility was stamping aluminum caps for pharmaceutical vials. They initially sourced 1100 aluminum because it was cheap and easy to punch. However, during the capping process, where a machine crimps the aluminum over the glass vial, the 1100 aluminum was so soft that the caps crushed and failed to create a sterile seal. They switched their specification to 3003 H18 aluminum coil. The full-hard temper provided the exact rigidity needed for the thin 0.2mm gauge sheet to hold its shape and seal the vial securely without crushing.
Industrial Applications
Based on their mechanical limitations and advantages, these materials serve entirely separate markets.
Typical Uses of 1100 Aluminum Sheet and Coil
- Electrical busbars and conductors
- Heat exchangers, fins, and radiators
- Deep-drawn chemical equipment and storage tanks
- Kitchenware and spun metal reflectors
- Architectural flashing and decorative trim
Typical Uses of 3003 H18 Aluminum Plate and Coil
- Bottle caps, ROPP closures, and vial seals
- Rigid, thin packaging materials
- Flat stamped components requiring high surface hardness
- Corrugated roofing sheets (where no sharp bending occurs)
Cost and Procurement Selection Guide
Cost Comparison: 1100 aluminum is generally less expensive to produce than 3003 because it requires no alloying additions and less extensive rolling to achieve standard tempers.
How to make the final procurement decision:
Choose 1100 Aluminum if:
- You are manufacturing electrical components or heat transfer equipment.
- Your design requires deep drawing, metal spinning, or sharp bending.
- You need the absolute highest level of chemical corrosion resistance.
- Structural strength is not a primary requirement for the finished part.
Choose 3003 H18 Aluminum if:
- You need high surface hardness and rigidity in a very thin gauge.
- Your product is essentially flat and will not undergo forming or bending.
- You require a higher yield strength to prevent denting or crushing in packaging applications.
Your Certified Supplier for 3003 and 1100 Aluminum Products
Specifying the correct alloy grade and temper is the foundation of a successful manufacturing run. Supplying your press brake operators with rigid 3003 H18 when they need the deep-drawing capability of 1100 will completely halt your production line.
We operate as a global industrial supplier, processing high-quality aluminum products strictly to ASTM B209 and EN 485 standards. Whether you need the high electrical conductivity of 1100 aluminum sheet for heat exchangers, or the rigid, high-hardness characteristics of 3003 H18 aluminum coil for closures, we possess the massive inventory to fulfill your requirements. We provide comprehensive custom processing, including precision cut-to-length services, custom width slitting, and mixed-alloy container loading to optimize your supply chain logistics.
Ready to eliminate material specification errors and lower your raw material costs? We maintain heavy stock of both 1100 pure aluminum and 3003 H18 manganese alloy ready for immediate global shipment. Send us your required specifications, thicknesses, and end-use application today. Our export sales engineers will provide a highly competitive, factory-direct quotation along with full Mill Test Certificates (MTC) within hours. Contact us now.
