GALVANIZED steel , prepainted steel performance test

1.The testing standards

Pre paint steel sheet and steel strip test methods” (GBT l344B-2006)

Coating aging performance evaluation according to ” Paint and varnish coating aging rating method” (GB / T 1766-1995)


2.The testing conclusion

Testing Hwafone’s pre paint steel sampling immediately, and comparing this with major factories in Shandong by using same specifications and same color. By contrast test, the various performance indicators demonstrate Hwafone’s pre paint steel is identical or showing significant performance advantages.

Hwafone’s product quality will be further improved by optimizing production management process and strengthening the supervision of the main raw materials.


3.Pre-painted steel performance testing including visual inspection, physical performance testing and ageing resistance and Corrosion resistance test

1, visual inspection including color testing and glossiness test

2, physical performance testing include coating thickness measurement, hardness testing (pencil hardness, scratch hardness), flexibility testing (impact, the shaft bends, T bend, cup drawing, stretch), adhesion test (scratch test), degree of curing test (glass transition test, solvent resistance test, the dry heat test), other performance testing (Pressure spot test, baking test, stain resistance test, chemical resistance test, the abrasion test, Drop test, the coefficient of friction test);

3, ageing resistant, corrosion resistant test including natural aging test (atmospheric exposure test), salt spray test, humidity test, Xenon lamp aging test, UV lamp aging test etc.


4.visual inspection items

Color deviation test

This is using a portable colorimeter online to test color deviation for each pre painted coil. Testing spectral tristimulus values for reference sample and test sample by colorimeter, the color differences can be quantitatively determined. As pre painted steel is generally used outdoors, so the determination of its color, the colorimeter of light is generally use simulation of the midday sun of D65 light.

The original sample is generally provided by the customer, or customer confirmed pre-painted steel.

salt spray test







Comparing the results

The sample quality inspection report:

The finished product sample:galvanized steel sheet 0.45mm primer:5±1um top coat:12±1um back coat:12±1um


Test Item RESULTS Test standard
Paint appearance Flat and smooth GB/T+1725-2007
pencil hardness ≥ 3H GB/T13448-2006
Gloss/60° 45±5 GB/T13448-2006
impact 9J No peeling GB/T13448-2006
bending test 3T No peeling GB/T13448-2006
MEK ≥ 100 times GB/T13448-2006
salt spray test(500h) rusting≤ 2mm,blister 0 JIS K 5600-4-3
ultraviolet aging QUV A (1000h) Δ E ≤ 4 Δ GR ≥ 50% pulverization:No.0 Than No.0 GB/T 1766-1995