Does the aluminum alloy guardrail on your balcony shake? Is the newly replaced aluminum alloy window with thermal break tightly closed? Behind these daily observations lies the profound knowledge of the national standards for aluminum profiles. From architectural doors and Windows to industrial frames, the quality of aluminium profiles is directly related to safety and durability. Today, we will break down the key indicators in the national standards in plain language and teach you to avoid purchasing traps.
1. Material: Recognize these two "ID cards"
Just as food has a composition table, the "genes" of aluminum profiles are determined by GB/T 3190-2008 "Chemical Composition of Wrought Aluminum and Aluminum Alloys". This national standard clearly stipulates the chemical composition requirements for raw materials and serves as the first checkpoint to prevent inferior aluminum materials from entering the market.
The most common aluminum profiles in daily life can be divided into two major camps: building profiles mostly use 6061 and 6063 grades of alloys. Among them, industrial profiles in the 6063-T5 state need to reach a Vickers hardness of ≥8HW (about 56HB), and no marks can be left when scratched by a fingernail to be qualified. When making a purchase, you can ask the merchant to show the material certificate and verify the alloy grade and hardness index.
Product standards must be even more vigilant: architectural profiles must comply with GB 5237-2008, while industrial profiles should follow GB/T 6892-2006. The former adds corrosion resistance requirements for scenarios such as doors, Windows and curtain walls, while the latter focuses more on mechanical properties. Don't let merchants pass off industrial profiles as construction-specific materials.
Ii. Is thicker wall thickness always better? The national standard gives you the standard answer
"Boss, give me the thickest aluminium material!" This kind of purchasing misunderstanding should be corrected. The national standard's regulations on wall thickness are full of hidden mysteries:
The nominal wall thickness of architectural window profiles should be no less than 1.2mm, but there are certain requirements in actual measurement - the solid part should not be less than 1.05mm, and the hollow cavity part should be no less than 0.97mm. The requirements for door profiles are stricter. The actual wall thickness of the main load-bearing parts must be ≥2.0mm. When measuring with a caliper, several more points should be measured.
Although there is no uniform minimum wall thickness requirement for industrial profiles, it is by no means the thinner the more cost-effective. It is recommended that the load-bearing frame be made of profiles with a wall thickness of ≥3mm, and be designed with reinforcing ribs to achieve both weight reduction and strength. Remember: The wall thickness that conforms to the design load is the optimal solution.
The tolerance grade directly affects the installation effect. GB 5237-2008 classifies architectural profiles into three grades: the common grade allows a wall thickness error of ±0.15mm, the high-precision grade tightens it to ±0.10mm, and the ultra-high-precision grade is only ±0.07mm. When installing, if the window is not closed tightly and the frame is skewed, it is very likely that the fault is caused by excessive tolerance.
Three, these hidden indicators determine the service life
Aluminum profiles with insufficient hardness are like calcium-deficient bones. Press the surface of the profile lightly with a Vickers hardness tester. If the reading of 6063-T5 profile is lower than 8HW, be vigilant. Such materials are prone to deformation and affect the sealing performance of doors and Windows.
There are also tricks to length tolerance. The standard profile is 6.02 meters long (with sufficient cutting allowance), and the custom longest can reach 7.5 meters, but the cutting error must be ≤0.5mm. The complaints from installation workers about "dimensions not matching" are often caused by substandard cutting accuracy.
Production management standards are equally important. Manufacturers that have passed ISO 9001 certification are more reliable. Full-process quality control can prevent performance differences in the same batch of profiles. When verifying the certification certificate, pay attention to the validity period and whether the certification scope includes the production of aluminum profiles.
Iv. Guidelines for Material Selection and Acceptance in Different Scenarios
For door and window projects, do not be frugal with materials: Prioritize high-precision and above profiles. Use a micrometer to measure the wall thickness (with a focus on checking the joints). Returns must be made if the twist exceeds 1.0mm/m. It is recommended that high-rise buildings be upgraded to ultra-high precision grade to ensure better wind pressure resistance performance.
For industrial scenarios, customization is available on demand: The straightness of the assembly line frame is highly valued, and the bending degree must be ≤1.0mm/m to ensure the installation accuracy of the equipment. Load-bearing structures need to undergo load tests; it is not enough to just look at the wall thickness.
When accepting, prepare a three-piece set: a Vickers hardness tester to measure hardness, a digital micrometer to measure wall thickness, and a laser level to check straightness. Key data should be photographed and archived. The inspection records should be kept for at least two years so that there is evidence to rely on when problems occur.
National standards are the bottom line of quality rather than the upper limit. When choosing aluminium profiles, for ordinary household doors and Windows, do not choose less than high-precision grade. For special scenarios (such as coastal areas and chemical plants), an additional salt spray resistance test report should be required. Remember: Qualified aluminium profiles can not only withstand ten years of wind and rain, but also safeguard safety in unexpected situations. Next time you choose aluminum materials, follow this national standard guide and you won't go wrong!
