Facebook Twitter YouTube

Unicoil Processing Banner

The Processing Flowchart

Process Lines

* Click process illustration to view actual image.

Color Coating Line Color Coating Line Hot Dip Galvanizing Line Push-Pull Pickling Line Cold Rolling Mill

*HS CODE - Harmonized System Code

The production process for metallic coated and organic coated steel starts with the pickling of hot-rolled coils in order to remove the iron oxide scale that is formed during hot rolling of steel. The product after pickling is known as HRPO ("hot-rolled pickled and oiled"). Hydrochloric acid is used for pickling, and the spent acid is regenerated in an acid regeneration plant. The cold-rolling mill reduces the thickness of the HRPO coils to the required thickness, with the percentage reduction usually being within the range of 50–90%. The product after cold rolling is known as cold-rolled, full-hard steel. The continuous hot-dip galvanizing line has an inline annealing furnace, with an atmosphere comprised of a mixture of nitrogen and hydrogen to avoid oxidation of the steel, followed by a molten zinc pot to galvanize the steel. The inline furnace softens the steel through an annealing process, while the molten zinc pot, along with an air wiping mechanism, controls the application and mass of zinc coated on the steel. The product after zinc coating is galvanized steel. The zinc coating provides corrosion resistance to the steel through barrier and sacrificial protection. Galvanized steel is available in different coating designations based on the zinc coating mass, and is available with regular spangle and mini-skin-passed spangle surfaces. While galvanized steel with a regular-spangle surface finds applications in many industries, including ducting, the product is not suitable for applications requiring painting. Mini-skin-passed spangle, which has a uniform surface texture, is the most suitable product for painting applications. The color coating line includes an online pretreatment section to clean the galvanized steel, followed by application of an organic primer coating and an organic finish coating, with each coating followed by curing in an oven, which finally yields prepainted galvanized steel. The primer coating provides the corrosion resistance and the finish coating provides the color and aesthetics. Prepainted galvanized steel is used in many applications in the construction industry, along with other applications such as home appliances, garage doors, and automotive parts.

The UNICOIL process lines are described briefly below.

Main Production Lines

Push-Pull Pickling Line (PPPL)

The turbo-pickling technology cleans the hot-rolled steel strip with hydrochloric acid and ensures the removal of scale prior to rolling the material. The strip edges are trimmed and prepared by an online side trimmer in accordance with the specific width requirements of the customer in the pickling line. The spent acid is regenerated in the acid regeneration plant and then reused, making the whole process environmental friendly.


Iron Oxide


Packed Iron Oxide


Hot Rolled Trimming


Packed HR Trimming

Bi Products

Cold Rolling Mill (CRM) - Full Hard

The cold-rolled reversing mill reduces the pickled and trimmed hot-rolled coils to a specified thickness, ranging from 2 mm right down to 0.20 mm. The work roll-shifting mechanism coupled with a selective roll coolant system guided through an auto shape meter ensures that the produce strip is perfectly flat. The auto gauge control system yields close thickness tolerances that match the international standards.

CR Pup Coils

Full Hard Cold-Rolled Pup Coils

Bi Products

Continuous Galvanizing Line (CGL)

The vertical nonox furnace technology in the galvanizing line uses natural gas to thermally clean the cold-rolled strip by creating a non-oxidizing atmosphere that volatilizes surface hydrocarbons on the strip. In the annealing section of the furnace a mixture of nitrogen and hydrogen gases protects the strip from oxidation as well as preparing the strip for zinc coating. Performing alkali cleaning before the furnace also assists in obtaining excellent zinc adherence.

An online X-ray coating weight gauge controls the accuracy and uniformity of the coating across the width and along the length of the strip, while the skin-pass mill and tension leveler ensure that the strip is flat prior to recoiling.

Zinc Dross

Zinc Top Dross

Zinc Dross

Zinc Top Dross Packed

Bi Products

Color Coating Line (CCL)

The seven-stage pretreatment process yields a clean galvanized strip with a conversion coating, which is followed by a two-coat, two-bake process to provide aesthetically superior prepainted galvanized steel with good metal-to-paint adhesion and uniform color, paint thickness, and surface finish. This produce is suitable for various applications including in construction, domestic appliances, garden fencing, and garage doors.

UNICOIL quality symbolizes the very best in the industry. UNICOIL has earned the status of market leader throughout the Middle East. Our products are now exported to Asia, Africa, Europe, and the USA.

Copyright © 2017 UNICOIL. All Rights are Reserved
Last Updated on Saturday June 24 of 2017