Galvanized Processing Point


Galvanized Processing Point

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A. ENTRY SECTION

Entry Section

Dual 15 tones capacity pay-off reels provide a continuous supply of cold rolled strip to the line. Trailing and leading ends of feed coils are joined by a narrow lap seam welder and a horizontal looper provides sufficient strip storage to enable the process section of the line to continue running at up to 70 m/min. while this joining is carried out.


B. FURNACE SECTION

Furnace Section

In addition to heat treatment to produce the required mechanical properties of the base steel, the furnace section burns off the residual rolling oil from the cold rolling process. A controlled furnace atmosphere and an extension of the furnace which penetrates below the surface of the molten zinc in the galvanizing pot ensure that the strip surface is perfectly clean and free from oxides or contamination on entry to the molten zinc. This condition is essential to the obtaining of a tightly adherent galvanized coating.


C. COATING SECTION

Coating Section

The galvanizing bath containing high purity zinc (99.7%) is added carefully with controlled quantities of lead and aluminum. After exiting from bath, the galvanized strip goes through a fully closed loop system for controlling zinc coating thickness. The galvanized strip first vertically passes through a pin hole detector which gauges the coating of the zinc on the strip and the feedback this information to the computer. The computer then regulates the desired zinc coating thickness through a set of air knives. These air knives not only regulate the zinc coating thickness with high precision, they also make sure the zinc is coated or distributed evenly on each side of the galvanized strip.


D. POST COATING SECTION

Post Coating Section

To solidify the galvanized coating and to reduce the temperature of the strip to that necessary for tension leveling, the strip progress trough a series of air cooling ducts and a water mist spray.


E. TENSION LEVELING and CHROMATE SECTION

Tension Leveling and Chromate Section

Depending on whether the end application material is tension leveled to ensure that the finished product meets all requirements of flatness and finish. Finally a chemical treatment is applied which provides protection to the trip surface against storage skin.


F. EXIT SECTION

Exit Section

Finished product is recoiled into customer specified coil weight. Usually, coil weight range from 2 MT to 5 MT.