Luggage hardware hardness of electrophoretic lattice frame -B

Fourth.hardness test methods and standards

Luggage hardware commonly used test methods

Pencil hardness test

According to GB/T 6739 standard of luggage hardware, use a pencil of known hardness to scratch at an angle of 45°, and take the highest hardness value without scratch as the result.

Vickers hardness (HV)

for thin coatings (<50μm), the hardness value is calculated by the diagonal length of the indentation.

Knoop hardness (HK)

more accurate hardness measurement of small areas, suitable for localised hardening treatments.

Luggage hardware standard references

Automotive industry standards ( GMW 14872) require electrophoretic coatings to have a pencil hardness of ≥3H and a scratch resistance (under 500g load) of ≤3mm scratch width. Industrial equipment standards may be more stringent, HV ≥ 200.

Fifth.hardness performance in practical applications

Scratch resistance

Hardness and scratch resistance are not linearly related. For example, a coating with HV300 may be scratch-free under a force of 5N, but a coating with HV250 may perform better with the addition of a lubricant (such as silicone oil).

Environmental Adaptability

High temperature and high humidity environments (such as 85°C/85%RH) may cause the coating to soften and the hardness to drop by 20-30%. Long-term hardness stability needs to be verified by ageing tests.

Sixth.recommendations and directions for optimisation

Process optimisation

Adjust the pH (5.5-6.5) and conductivity (1000-1500μS/cm) of the electrophoresis solution to improve the densification of the coating.

Adopt UV curing technology for the lattice layer, which can shorten the curing time to within 10 seconds and increase the hardness by 15%-20%.

Luggage hardware material Selection

For scenes requiring high hardness (outdoor signage), a combination of stainless steel substrate + epoxy electrophoresis + two-component polyurethane lattice frame is recommended.

For lightweight requirements, aluminium alloy substrate can replace part of the electrophoresis layer function by anodic oxidation pretreatment (hardness HV300-400).

Quality Control

Spot check coating thickness (using eddy current thickness gauge) and hardness per batch to ensure compliance with standards.

Establish a correlation database between hardness and weathering and chemical resistance to guide process adjustment.