Soft Temper (O) vs. Hard Temper (H18) Plain Aluminum Foil: Applications & Processing Differences

When purchasing plain aluminum foil (bare aluminum foil) in jumbo rolls, selecting the correct temper state is just as crucial as choosing the right alloy. The temper—such as Soft Temper (O) or Hard Temper (H18)—determines how the foil behaves during bending, stamping, lamination, and conversion.

Here is a breakdown of the key processing differences and applications between O temper and H18 aluminum foil.

1. Soft Temper (O Temper): Ultimate Flexibility & Dead-Fold

Annealed to a fully softened state, O temper foil has low tensile strength but high elongation and ductility.

Key Characteristics: Excellent dead-fold property (retains its shape after folding without springing back), low springback, and high formability.

Best Applications: Flexible packaging lamination, chocolate and butter wrappers, cable wrapping, and pharmaceutical pouch backing.

Caption: Fully annealed O temper plain aluminum foil offering superior dead-fold characteristics.

2. Hard Temper (H18): High Tensile Strength & Rigidity

H18 temper represents fully work-hardened aluminum foil, offering maximum tensile strength and structural rigidity.

Key Characteristics: High tensile strength, high springback, and resistance to stretching or tearing under high-speed tension.

Best Applications: Household foil rolls, semi-rigid food containers, lidding foils, battery current collectors, and industrial duct tape backing.

Caption: High-strength H18 plain aluminum foil engineered for rigid container manufacturing.

Processing Summary: Which One Should You Choose?

Choose Soft Temper (O) if your process involves complex folding, deep drawing, soft lamination, or contour wrapping.

Choose Hard Temper (H18) if your line requires high-speed unwinding, rigidity, household cutter box packaging, or container stamping.

Looking for Custom Temper Plain Aluminum Foil?

We supply factory-direct 1235, 8011, and 8079 plain aluminum foil rolls in both O and H18 tempers with Grade A degreasing. Contact our technical sales team today for free sample rolls and quotes!