How does cold rolling process affect the quality of hot-dip galvanizing products?
(1) the cold rolling process shall strictly control the plate shape process conditions, and any plate shape defects will lead to uneven coating.
(2) the content of oil in the rolling emulsion should be strictly controlled in the cold rolling process.Because, with the increase of oil content in the rolling emulsion, the super high oil content may not be removed in the preheating furnace, and affect the decrease of zinc layer adhesion.
(3) the winding tension of the cold rolling plate shall be strictly controlled in the cold rolling process.Because the size of winding tension has a direct impact on the hot galvanizing process.
A. Too little tension in coiling, easy to collapse coiling.
B. too much winding tension can cause the inner ring of the strip to wrinkle.
What are the quality conditions of hot-dip galvanized sheet?
(1) the original plate tape must be tied neatly, and the tower roll and loose roll are not allowed to enter the work line.
(2) the width and thickness tolerances shall be met.
(3) the steel plate shall not have red rust on its surface.Therefore, the raw material placement field must be kept dry. If serious rust is found on the surface, remove the red rust before galvanizing.
(4) the edge of the strip should be smooth and free of cracks.
(5) the strip shall have sufficient coil weight to ensure the continuity of hot galvanizing operation.
(6) the surface of the original plate shall be clean.For the cold rolling mill, the cleaning degree of the surface mainly depends on the contamination degree of the rolling emulsion.
(7) the original plate shall be flat to ensure the normal operation of the strip in the operation of the unit.The original plate with defects such as wave shape, wave edge and sickle bend shall be rejected for galvanizing.