What Processing Are The Commonly Used Tempers H14, H16 And O of Color Coated Aluminum Strips Suitable for Respectively?

Abstract

Color coated aluminum strips integrate aluminum substrate ductility and polymer coating weather resistance, which are widely adopted in architectural decoration, household appliance manufacturing and advertising sign production. Substrate temper directly determines bending, stamping and deep drawing processing performance, and improper temper matching will cause coating cracking, substrate fracture and residual deformation. This article systematically elaborates the mechanical characteristics and targeted processing scenarios of three mainstream tempers (O, H14, H16) for color coated aluminum strips, and summarizes practical temper selection principles for downstream manufacturers.

1. Definition of Aluminum Strip Temper Markings

According to the Aluminum Association international marking standards, temper codes describe cold working and annealing treatment of aluminum substrates before color coating. The color coating process (PE/PVDF roller coating) will not change the inherent mechanical properties of the aluminum substrate. Core definitions of the three common tempers are listed as follows:

• O temper: Fully annealed soft temper. The substrate undergoes high-temperature homogenization annealing after cold rolling, with zero residual cold work stress, the lowest hardness and the highest elongation among mainstream tempers.

• H14 temper: Quarter-hard strain-hardened temper. No post-cold rolling annealing; the substrate completes 25% cold rolling deformation, achieving balanced strength and ductility.

• H16 temper: Half-hard strain-hardened temper. No post-cold rolling annealing; the substrate completes 37.5% cold rolling deformation, with higher tensile strength and lower ductility than H14.

For conventional 1050 and 3003 series color coated aluminum strips, the elongation rate decreases sequentially: O>H14>H16, while tensile strength increases sequentially: O<H14<H16.

2. Processing Application of O Temper Color Coated Aluminum Strips

2.1 Core Mechanical Advantages

O temper substrates have an elongation rate of 18%-25% and ultra-low yield strength. The internal crystal structure is fully relaxed without residual stress. Most critically, the soft substrate can undergo large plastic deformation without damaging the organic color coating. It avoids transverse coating cracks which frequently occur in hard tempers during deep forming.

2.2 Suitable Processing Types and End Uses

O temper is exclusively applied to severe secondary forming processes requiring multi-directional stretching. First, it matches deep drawing processing for curved household appliance components, including refrigerator inner liner decorative baffles, air conditioner curved surface side panels and microwave oven outer casings. These parts require 90-degree repeated folding and arc deep drawing with bending radius less than 0.5 times strip thickness, which cannot be realized by H-series hard tempers. Second, it adapts to hyperbolic bending for architectural special-shaped decorations, such as curved curtain wall aluminum veneers and arc ceiling trim strips used in shopping mall atriums. Third, it is suitable for embossing and compound rolling processing for interior decorative aluminum strips, as soft substrates ensure uniform coating distribution after surface texture deformation.

2.3 Processing Limitations

O temper strips suffer from poor rigidity and are prone to local denting under external impact. They cannot be used for exposed structural parts without reinforcing ribs, and will undergo irreversible creep deformation under long-term wind load.

3. Processing Application of H14 Temper Color Coated Aluminum Strips

3.1 Core Mechanical Advantages

H14 temper has a tensile strength of 190-230 MPa and elongation of 10%-15%. It retains sufficient ductility for conventional cold bending while improving anti-deformation rigidity by nearly 60% compared with O temper. It is the most versatile balanced temper for color coated aluminum strips, with excellent coating bonding stability after single-angle bending.

3.2 Suitable Processing Types and End Uses

H14 targets moderate single-time cold bending and shallow stamping processes with no repeated secondary forming. In architectural processing, it dominates linear exterior wall baffles, rainwater gutter bending forming and indoor integrated ceiling panels. These products only need one-time 90-degree right-angle bending with bending radius 1-1.5 times strip thickness, with no subsequent stretching. In advertising manufacturing, it is used for light box fascia and roadside billboard edge folding, requiring flat surface rigidity to prevent mid-span sagging. In household appliances, it applies to flat back panels of washing machines and non-curved decorative frames. Besides, H14 is the preferred temper for roll-forming continuous production, matching high-speed slitting and longitudinal bending assembly line processing.

3.3 Processing Limitations

Repeated folding or deep arc stretching will cause micro-cracks on the color coating surface. It cannot replace O temper for hyperbolic forming scenarios.

4. Processing Application of H16 Temper Color Coated Aluminum Strips

4.1 Core Mechanical Advantages

H16 half-hard temper has a tensile strength of 230-270 MPa and elongation reduced to 7%-11%. Its surface flatness and wind pressure resistance are significantly enhanced, with minimal elastic rebound after low-angle bending. The substrate has strong anti-scratch and anti-dent performance, adapting to harsh outdoor service environments.

4.2 Suitable Processing Types and End Uses

H16 is designed for minimal forming processing and structural load-bearing scenarios, only supporting gentle single-angle bending (bending radius ≥2 times strip thickness). The largest application is exterior building enclosure components: roof color coated aluminum tiles, external wall wind-resistant decorative panels and tunnel internal anti-corrosion aluminum liners. These components bear sustained wind pressure and temperature alternating stress, and require long-term flatness without deformation. Second, it is used for logistics equipment decorative cover plates and outdoor electrical box shells, which need impact resistance and rarely require post-coating forming. Third, it fits precision slitting without bending: thin color coated aluminum strips for cable shielding wrapping, where flatness and dimensional stability are core indicators rather than formability.

4.3 Processing Limitations

Any small-radius bending will lead to simultaneous fracture of substrate and color coating. H16 strips are not allowed for any deep drawing or multi-angle folding processing.

5. Comparative Selection Guide for Practical Production

6. Conclusion

The selection of color coated aluminum strip temper follows a clear formability-rigidity trade-off logic. O temper serves all large-deformation secondary forming processes with low structural load requirements; H14 acts as a universal option balancing forming efficiency and surface rigidity for conventional architectural and household appliance bending; H16 prioritizes structural stability and outdoor durability for components with negligible post-coating forming. Downstream processors should confirm bending times, bending radius and service load before temper selection to eliminate coating failure and substrate deformation risks.