1100 Aluminum Sheet Tempers:O, H14, H16, H18, H24

1100 pure aluminum sheet is the most widely used pure aluminum sheet in industrial applications. With an aluminum content of ≥99.00%, it offers excellent corrosion resistance, thermal and electrical conductivity, plasticity, and weldability. It is highly cost-effective and widely used in industries such as architectural decoration, chemical anti-corrosion, electrical heat dissipation, and sheet metal fabrication.

1100 pure aluminum cannot be strengthened by heat treatment; its mechanical properties are determined entirely by cold work hardening and annealing processes. The five common tempers on the market are O, H14, H16, H18, and H24, which differ significantly in hardness, plasticity, and workability.

I. Basic Understanding

The O temper represents the fully annealed, soft state—the material's original condition—offering the highest plasticity and lowest hardness. The H series represents cold work-hardened states; higher numerical values indicate a greater degree of cold working, resulting in higher hardness and strength but reduced plasticity and ductility.

The H1 series undergoes pure cold work hardening without annealing. The H2 series represents a semi-hardened state achieved through partial annealing after cold working; it balances strength and toughness, resists cracking, and is well-suited for sheet metal processing. The general performance trends are: Hardness H18 > H16 > H14 > H24 > O; Plasticity O > H24 > H14 > H16 > H18.

II. Five Common Tempers

1. 1100-O Temper

This is a soft aluminum sheet produced via high-temperature full annealing. It features uniform, stable internal grain structures and is free from processing stresses. It offers excellent ductility, effectively eliminating cracking issues during bending or stretching, and provides the best formability among 1100 aluminum tempers.

1100 0 aluminum sheet exhibits stable mechanical properties—tensile strength of 75–105 MPa, yield strength ≥25 MPa, and elongation of 20%–35%—making it suitable for complex, irregular shaping processes.

It is primarily used for deep-forming applications requiring high plasticity, such as deep-drawn cookware, thin-walled irregular parts, aluminum foil for food packaging, flexible aluminum tubing, curved decorative components, and deep-drawn storage tank liners. Its drawbacks are insufficient strength and rigidity, making it unsuitable for use as load-bearing structural components.

2. 1100-H14

Aluminum 1100 h14 is the most common and classic general-purpose temper for 1100 aluminum sheet. Produced via moderate cold-rolling without annealing, it is classified as a standard "half-hard" temper.

This temper offers an ideal balance between strength and ductility; it is sufficiently rigid to resist deformation while allowing for smooth execution of standard processes such as bending, leveling, and cutting. It offers high processing tolerance and carries almost no risk of cracking. Mechanical properties (reference): Tensile strength 95–125 MPa, yield strength ≥75 MPa, elongation 3%–10%.

It is a mainstream choice in the construction, hardware, and advertising industries. It is frequently used for thermal insulation jacketing, curtain wall backing panels, equipment covers, advertising signage, standard bent sheet metal parts, and electrical appliance liners, offering excellent cost-effectiveness.

3. 1100-H16

H16 involves a higher degree of cold working than H14, placing it in the "medium-hard" category. The sheet exhibits significantly higher rigidity and deformation resistance, along with superior surface flatness, making it less prone to warping or distortion after processing. Compared to H14, its ductility is reduced; it supports only simple bending and is unsuitable for complex deep-drawing processes.

Mechanical properties (reference): Tensile strength 130–165 MPa, yield strength ≥115 MPa, elongation 3%–6%. It is primarily suited for applications requiring high flatness and rigidity, such as decorative panels for precision equipment, radiator substrates, formed sheet metal parts, wear-resistant outdoor decorative panels, and simple structural guards.

4. 1100-H18

H18 represents the highest level of cold-work hardening for 1100 aluminum sheet. Processed via intensive cold rolling, it achieves peak hardness and strength for this alloy grade. The sheet is highly rigid and stable, resisting deformation under load; however, its ductility is extremely poor. It possesses virtually no capacity for bending or deep drawing, and forced processing is likely to cause cracking.

Mechanical properties (reference): Tensile strength ≥150 MPa, yield strength ≥145 MPa, elongation only 2%–5%. Suitable only for applications that do not require secondary forming and prioritize rigidity and wear resistance—such as mechanical mounting plates, rigid aluminum shims, sign backings, heat sink fins, and wear-resistant liners—and which require only simple processing like cutting or punching.

5. 1100-H24

The H24 temper utilizes a process combining "strain hardening" and "partial controlled annealing," resulting in a high-quality semi-hard state superior to H14. Compared to the purely strain-hardened H14, H24 offers lower internal stress, greater toughness, and better crack resistance; it exhibits uniform spring-back during bending and higher forming precision while maintaining good strength, making it the preferred choice for precision sheet metal work.

Key difference: H14 offers better cost-effectiveness and is suitable for standard processing; H24 offers more stable performance and is suited for high-precision, demanding bending and forming processes. It is primarily used in high-end applications such as precision sheet metal parts, architectural bent profiles, electrical enclosures, protective guards for precision equipment, and complex, multi-bend components.