The basic concept of color coated plate:on the  continuous  unit  to  cold-rolled   strip  steel, galvanized strip steel (electric galvanizing and  hot  dip  galvanizing)as  the  substrate,after surface pretreatment(degreasing and chemical treatment),using  the roll coating method, coated with one or more layers of liquid paint, baking and cooling the resulting sheet is the   coated steel plate. The basic concept of color coated plate:on  the continuous unit to cold-rolled strip steel,  galvanized strip steel (electric galvanizing and  hot  dip  galvanizing)as  the  substrate,after  surface pretreatment (degreasing and chemical treatment),using the roll coating method, coated with one or more layers of liquid paint, baking  and  cooling  the  resulting  sheet  is  the coated  steelplate.Because the coating can have a variety of different colors,it is customary to call the coated steel plate color coated steel plate. Coated  steel  plate  has  light  weight,beautiful appearance and good corrosion resistance,and can be directly processed,it provides a new type of raw material  for the  construction  industry,shipbuilding industry,vehicle manufacturing industry,furniture industry,electrical  industry,etc,has  played a good effect of replacing wood with steel,eficient construction,energy saving,pollution prevention and so on.The use of galvanized steel plate for the color coated steel plate,in addition to zinc protec- tion,the organic coating on the zinc layer plays a covering isolation role,can prevent the steel plate rust,the service life is longer than the  galvanized steel plate,according to reports,the service life of the coated steel plate is 50%longer than the galvanized steel plate.However,in different regions and different parts of use,using the same amount of galvanized,the same paint,the same coating thickness of the color coated plate,its service life willbe very dfferent. For example,in industrialareasor coastalareas,due to the action of sulfur dioxide gas or salt in the air,the corosion rate is accelerated,and the service life is ffect- ed.In the rainy season,the coating is soaked by rain fora long time,or  in the parts where the temperature difference between day and night is too large and easy to dew,it will be corroded faster,and the service life will be reduced.