Galvanized Steel Coil - Hansen Pole Buildings

Before Steel Coil Can Be Coated

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I think far too often we take for granted the many processes companies spend lots of time and resources (not to mention money) to give us products with features we come to take for granted.  Like making sure metal such as steel does not rust and corrode after years of use.  Before steel can even be painted, it goes through a series of steps to ensure the coating (painting) process is top of the line.  And not just for today, but for many years down the road.

Unprotected steel corrodes quickly as oxidation activity consumes the metal, but this process is preventable by protecting the steel from water and oxygen, thus interrupting the oxidizing action. Surface coatings such as paint are permeable to water and oxygen and eventually permit rusting. Hot-dip galvanizing, however alloys molten zinc to steel metallurgically and forms an impenetrable barrier to water and oxygen. The zinc coating, which is much more durable than painted coatings which often chip during assembly or exposure to the elements, then acts as a sacrificial anode protecting the steel from rust and corrosion, even if the surface has been damaged. Unpainted galvanized steel parts can last 25 years or longer without maintenance.

Galvanized steel coil is defined as a carbon steel sheet coated with zinc on both sides. Continuous hot dipping, or electro-galvanizing are the two processes used to produce both galvanized sheet steel and steel coil. Generally speaking, the hot dip process consists of passing the steel through a bath of molten zinc. The electro-galvanizing process consists of the application of zinc by electrolytic disposition. The result is a layer of zinc tightly adhering to the base metal through an iron-zinc bonding layer.

Continuous hot dipping is the process used in the application of zinc to steel coils which will later be roll formed into steel roofing and siding.

A zinc coating is one of the most effective and economical methods of protecting bare steel from a corroding environment. The zinc not only serves as a barrier between the steel and the environment, it will sacrifice itself to protect the underlying steel sheet. Sacrificial, or galvanic protection occurs when two dissimilar metals are in contact and coupled with water and oxygen. Zinc corrodes preferentially to the iron in steel. This protection prevents corrosion of the steel at areas not covered with zinc. Thus, the spread of corrosion from cut edges, drill holes, etc. is minimized.

Hot-dipped Galvanized products are manufactured to ASTM A-653 specifications, and are available in a variety of coating weights such as G-90, G-60, G-40, and G-30. With galvanization, the larger the “G” value, the thicker the zinc coating is. For related reading: https://www.hansenpolebuildings.com/blog//02/steel-siding-2/

Typical applications for Galvanized Steel Coil and Sheet products include exterior building products (like steel roofing and siding for pole buildings), ductwork, HVAC products, flashing, electrical boxes and other electrical products, roofing, doors, sashes, automotive parts, appliances, commercial and residential steel framing, truss plates (read more on truss plates here: https://www.hansenpolebuildings.com/blog//10/metal-connector-plates-have-teeth/ ), metal building purlins, and any other products requiring a corrosion resistant material.

Once the galvanized steel is protected, it moves on to the painting process – so stay tuned for tomorrow’s blog to learn the many magical steps of steel coil coating.

What is Galvanized Steel and How Is It Made?

Galvanized steel is a carbon flat rolled steel product that is covered in a zinc coating on its surface.  This coating increases a steel coil’s, slit coil’s, or sheet’s resistance to corrosion.  The most common method of galvanizing steel is the hot dip galvanized process.

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In the hot dipped galvanized process, base carbon steel coil is submerged in an acid bath to remove steel scale.  Once the steel is cleaned and its scale is removed, it is continually submerged in bath of molten zinc forming a metallurgical bond and protective coating at a controlled coating weight.  The coating weight immediately increases the corrosive resistance of the steel.

The zinc bath during the hot dipped galvanized process contains trace amounts of elements like aluminum.  The presence of these trace amounts optimize coating adhesion and improve the malleability of galvanized steel sheet, galvanized steel coil, and galvanized steel slit coil allowing the material to be formed into hundreds of products that we use every day. 

What Is Spangle On Galvanized Steel?

In previous steel making generations, galvanized steel sheet used to contain large, flowery crystalline patterns of zinc on the surface of the steel known as "spangle".  Spangle resembles large hexagonal snowflakes. Although today’s galvanized steel still contains spangle, modern steel mills produce galvanized steel with spangle that is virtually undetectable to the naked eye.  This is known as minimum spangle and zero spangle galvanized steel.

A common but disappearing misconception about large spangle galvanized steel is that it has better corrosion resistance than min spangle/zero spangle.  This is not the case.  Minimum spangle and zero spangle galvanized steel’s smoother surface and smaller spangle form a better corrosive resistance coating.

What Are Coating Weights?

The aforementioned zinc coating weights of galvanized steel are controlled by steel mills during the production cycle and vary depending on customer requirements and the ultimate end use of the product.  These coating weights are directly proportionate to the expected service life of the steel.

Zinc coating weights are measured in ounces per square foot and range from G90 to G60, G40, and G30 galvanized steel.  G90 galvanized steel has a longer service life than G60, G40, and G30 galvanized steel, because G90 galvanized steel has a heavier coating weight of zinc applied to it at 0.90 oz/ft^2 as opposed to G60 galvanized steel at .060 ox/ft^2 and so on.

Galvanized Steel In Everyday Use

The advantages of using galvanized steel are its relatively lower cost compared to products like stainless steel, its long life span, low maintenance, and it can be quickly produced. As a resuly, galvanized steel is used in thousands of products around us that we see and use every day. 

Hot dipped galvanized steel is used in industries such as HVAC, construction, roofing, appliances, container, waste, and the automobile business to name a few.  For example, in the HVAC business, galvanized steel sheet, coil, and slit coil (like 5.394” wide) are used to manufacture duct and spiral duct. Galvanized steel can either be pre-painted, post painted, or bare.  

Camden Yards Steel Galvanized Steel Stock

Camden Yards Steel carries a wide variety of galvanized steel products including but not limited to the following:

Galvanized Steel Sheet A653 CS TYPE B - 3x8, 3x10, 4x8, 4x10, 4x12, 5x8, 5x10, 5x12 and Custom Lengths (please inquire)

Gauge     Decimal     Width   Width   Width   Coating Weight
28 Gauge  . min   36"     48"     -       G30, G40, G60, G90
26 Gauge  . min   36"     48"     60"     G30, G40, G60, G90
24 Gauge  . min   36"     48"     60"     G30, G40, G60, G90
22 Gauge  . min   -       48"     60"     G30, G40, G60, G90
20 Gauge  . min   -       48"     60"     G30, G40, G60, G90
18 Gauge  . min   -       48"     60"     G30, G40, G60, G90
16 Gauge  . min   -       48"     60"     G30, G40, G60, G90
14 Gauge  . min   -       48"     60"     G30, G40, G60, G90
12 Gauge  . min   -       48"     60"     G30, G40, G60, G90
11 Gauge  . min   -       48"     60"     G30, G40, G60, G90
10 Gauge  .129 min    -       48"     60"     G30, G40, G60, G90

Galvanized Steel Coil A653 CS TYPE B - 5 ft, 4 ft, and 3 ft 20" ID 10,000# Max and 5,000# Max Galvanized Coil

Gauge     Decimal     Width   Width   Width   Coating Weight
26 Gauge  . min   36"     48"     60"     G30, G40, G60, G90
24 Gauge  . min   36"     48"     60"     G30, G40, G60, G90
22 Gauge  . min   -       48"     60"     G30, G40, G60, G90
20 Gauge  . min   -       48"     60"     G30, G40, G60, G90
18 Gauge  . min   -       48"     60"     G30, G40, G60, G90
16 Gauge  . min   -       48"     60"     G30, G40, G60, G90

Galvanized Steel Slit Coil A653 CS TYPE B - 5.394" Slit Coil for Spiral Duct & Custom Widths (please inquire)

Gauge     Decimal     Width     Coating Weight
28 Gauge  . min   5.394"    G30, G40, G60, G90
26 Gauge  . min   5.394"    G30, G40, G60, G90
24 Gauge  . min   5.394"    G30, G40, G60, G90
22 Gauge  . min   5.394"    G30, G40, G60, G90
20 Gauge  . min   5.394"    G30, G40, G60, G90
18 Gauge  . min   5.394"    G30, G40, G60, G90
16 Gauge  . min   5.394"    G30, G40, G60, G90

Please call Camden Yards Steel today with any of your galvanized steel sheet, galvanized steel coil, galvanized steel blanks, or galvanized steel slit coil needs any time at 856-342-.  As always, thanks for stopping by!