Color steel plate different quality problems arising from the characteristics and causes

1. Bad hardness

Characteristics: use the drawing pencil to scratch the surface of the coating with force, and leave a scratch on the surface after erasing.

Reason for occurrence:

①, furnace temperature is low, coating curing is not sufficient.

②, improper heating conditions

③, the coating thickness is thicker than specified

2. Spots

Characteristics: foreign matter or dust mixed from the outside in the coating after part or all of the surface with rice-like protrusion occurs

Reason

①, the paint is mixed with other types of paint or other companies.

②, foreign matter mixed in the paint.

(iii) Poor washing during pre-treatment.

3. Bending bad

Characteristics: When the steel is bent 180 degrees, the coating on the processed part is cracked and the coating is peeled off.

Reason:

①, the amount of pre-treatment mastery is too much.

②, the coating thickness is too thick.

Excessive baking.

(4) The manufacturer of the lower coating is different from that of the upper coating, or the thinner is used improperly.

4. Bump

Characteristics: Due to the impact of the steel strip by the outside, the surface of the plate protrudes or depressions, some have a certain spacing, and some do not occur

Reason:

①, foreign matter mixed in the roller when painting.

(②) Tie marks on thin plate products during strapping.

③, external impact when rewinding.

5. Bubble at the side

Characteristics: Both sides are stained with paint, after drying, bubbles occur.

Reason: the original material has a burr stained with paint, the two sides appear gap

6. Orange peel

Characteristics: the surface coating has been dried like orange peel as rough, uneven

Occurrence of reasons:

①, the wet film is too thick.

②, the viscosity of the coating is high.

7. Poor solvent resistance

Characteristics: Butyl ketone wiping point-like paint loss occurs

Reason:

①, the baking temperature does not meet the requirements

②, curing problems with the paint

③, pre-treatment cleaning is not clean