Galvanized Steel Coil

Galvanized Steel Coil is used cold rolled steel coil as substrates by a continuous hot-dip process. This method tightly adheres the coating to the steel with an iron-zinc alloy bonding layer formed by a diffusion process while the heated steel strip is in contact with the molten zinc. One of the drawbacks of Galvanized is that if the Zinc coating is scratched off the steel, the Steel is left unprotected, and is subject to failure. It has excellent corrosion resistance, paintability, and workability due to zinc’s characteristics. 

Specification

Galvanized Coating Layer

· Anti-Finger printing ,Chromated, Oiled/ non-oiled

· Zn Plating Layer (20-120g/sm)

· Cold Rolled Steel Sheet

Surface Structure

Spangled galvanized steel sheet is the spangle obtained by the condensation of the zinc coating under normal conditions after galvanizing. It is mainly used in buildings and other places where there is little direct contact with the human body.

Galvanized steel sheets without spangles are mainly produced through a special production process to control the lead in the zinc pot to a certain level, or after the strip steel is out of the galvanized pot, it undergoes special treatment to control the spangles to less than a certain level. Mainly used in home appliance housing 

Hot Dipped Galvanized Steel Coil Production

The manufacturing of galvanized steel coil&sheet with good weather resistance, primarily used in construction.

Galvanized steel coils production process:

1. Uncoiler

2. Welder

3. Entry Looper

4. Pre-treatment

5. Annealing Furnace

6. Zinc Pot

7. Cooling Tower

8. Water Quench Tank

9. Skin Pass

10. Tension Leveler

11. Passivation Coater

12. Exit Looper

13. Recoiler

The production and processing of galvanized steel coils can be divided into three steps: first, the entire coil is pickled to remove rust and dirt, so that the surface of the galvanized steel strip can achieve a bright and clean effect; after pickling, pass ammonium chloride or zinc chloride It is cleaned in an aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to the hot-dip plating tank for the galvanizing process; after the galvanizing process is completed, it can be put into storage and packaged.

Surface treatment of galvanized steel coil

Chromate treatment of galvanized steel coils is also called passivation treatment. Through passivation treatment, the surface structure and gloss of the galvanized layer can be improved, the corrosion resistance and service life of the galvanized layer can be improved, and the bonding force of the coating and the base metal can be improved.

The purpose of oiling galvanized steel coils is a protective layer is formed on the surface of the steel coil to prevent the surface from rusting.

Types of zinc coating of galvanized steel coil

Hot-dip galvanized coils are divided into pure zinc coating and zinc-iron alloy coating according to the coating. Their common point is that the zinc content of the zinc solution in the zinc pot is the same. The difference is that the zinc-iron alloy adds an alloying process.

pure zinc coating

In the hot-dip galvanizing production line, the pre-treated steel strip is immersed in the molten zinc bath to obtain the coating. The zinc content in the molten zinc solution should not be less than 99%.

zinc-iron alloy

A zinc-iron alloy layer is formed on the entire coating through an alloying treatment process, and the iron content in the alloy coating is usually 8-15%. During the alloying process, the galvanized steel coil is heated to 550-560°C in an alloying furnace in 5-10 seconds, so as to convert all the pure zinc layer into iron-zinc alloy. Its weldability, coating performance, heat resistance, and corrosion resistance are better than ordinary galvanized sheets.

For example:

EN 10346 DX51D+Z is pure zinc;

EN 10346 DX51D+ZF is zinc-iron alloy coating.

American ASTM A653 standard Galvanized Steel Sheet & Coil

· Commercial Steel (CS Types A, B, and C)

Commercial Steel is a low-carbon cold-formed steel, such as galvanized steel roof forming

· Forming Steel (FS Types A and B)

Requires higher drawability than Commercial Steel, such as for lamp cover forming

· Deep Drawing Steel (DDS)

· Extra Deep Drawing Steel (EDDS)

· Structural Steel (SS) – (33,37,40,50,80)

· High Strength Low Alloy Steel (HSLAS)

European EN 10346 standard galvanized steel coil

Low carbon steel for cold forming (DX51D – DX54D)

· DX51D is equivalent to Commercial Steel, curved and profiled

· DX52D is equivalent to Forming Steel

· DX53D is equivalent to Deep Drawing Steel

· DX54D is equivalent to Extra Deep Drawing Steel

Structural Steels (S220GD – S350GD)

S220GD,S250GD,S280GD,S320GD,S350GD

Use structural steel for high load-bearing capacity, with a yield strength of 220-350

Galvanized steel coil Uses

Galvanized steel coil has a wide range of applications, and its advantage is that it has a long anti-corrosion period. It is mainly used for home appliances, office panels, roof sheets, automotive panels, construction and substrate of prepainted steel coils.

Car board

The use of automotive plates must first be stamped and formed, and the steel plate is stamped into the required shape and size of the part.

Then spot welding, as an important welding method for thin plate connection, has a wide range of applications in the manufacturing industry, especially in the automotive industry.

Galvanized roof sheet

The performance requirements of galvanized roof panels mainly include the mechanical properties of the material (tensile strength, yield strength, elongation), coating performance (coating type, coating thickness and coating adhesion)

Home appliance office board

Including air conditioners, washing machines, refrigerators, photocopiers, etc., household galvanized sheets are mainly used for general forming applications and stamping.

Substrate

Another use of galvanized steel coils is to be used as the substrate of prepainted steel coils. prepainted steel coils have polyethylene coatings than galvanized coils and are more durable.