How to Choose Color of Pre-painted Steel?

Choosing the color of pre-painted steel sheet mainly depends on the matching with the surroundings, use purposes, and your own preferences. But considering the heat reflection ability, weather resistance, and other factors, the light-colored pre-painted steel is more recommended.

Reflectivity of Different Colors

The reflectivity of different colors is different. Generally, the higher the reflectivity of light, the less heat is absorbed, so the lower the temperature. The experimental data shows that the temperature of the white color coated steel surface is 10 degrees lower than that of the blue ones and 19 degrees lower than that of the black ones. So if the local climate is hot, light-color steel sheets are better for roofing or wall panels.

Below is a table showing the reflectivity of different colors.

Colors	Reflectivity	Reflection effect
White	84%	Great
Milky white	70.4%	Good
Light red	69.4%	Good
Beige	64.3%	Good
Light green	54.1%	Good
Light blue	45.5%	Medium
Brown	23.6%	Poor
Black	2.9%	Very poor

For color-coated steel sheets, the thermal expansion rate of the coating and the steel sheet is different. In particular, the linear expansion coefficients of the metal substrate and the organic coating are quite different. When the temperature changes, expansion or contraction stress will occur at the interface between the substrate and the coating. If they are not properly released, the coating will crack.

Color Retention

The exposure tests (8 years of exposure to the sun in Hainan Province) of the same paint and different colors show that the light color paint has less discoloration. The following table shows the exposure test results of different colors.

Colors	Original gloss	Current gloss	Color difference	Original thickness	Current thickness	Degree of chalking
White	35%	3%	1.49	24μm	20μm	Level 2
Red	45%	3%	2.48	24μm	20μm	Level 2
Light yellow	26%	2%	1.26	24μm	17μm	Level 2
Green	41%	2%	3.43	24μm	17μm	Level 2
Blue	41%	2%	4.95	24μm	17μm	Level 2

There will be color differences if you use prepainted steel sheets from different manufacturers or batches in the same construction projects. The color may look the same or similar during construction, but there will be serious color differences after several years. Therefore, it is strongly recommended to order the same batch for the same project at one time. Different batches even from the same supplier may use different paints, which will increase the possibility of color difference.

Coating Gloss

The choice of coating gloss is mainly according to the use purposes. For example, medium and low gloss color coated steel is mainly for construction uses; while high gloss color-coated steel is mainly for home appliance uses. 

Conclusion

The color of pre-painted steel can be customized according to the RAL color card. Generally, the different colors have little difference in price. Also, you can choose different finishes, such as matte, gloss, embossed, etc. You can choose based on the architectural style, use purpose, and your preference. In addition, Wanzhi Steel offers printed pattern steel products, such as wood grain, brick grain, camouflage pattern, grass, flower, etc. to better meet your needs. Please note that you need to pay more attention to the base metal, paint types, paint thickness, etc. when selecting color coated steel. If you have any problems, please talk with us.