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What is Powder Coating Steel & Why You Should Know?

Posted on: May 6th, 2019 by byersbushblog

Every type of metal has unique characteristics.  Those characteristics will affect how a powder coated finish responds to the surface of the metal.

The properties of the base metal and the surface characteristics of the finished metal will both impact its suitability for powder coating. Therefore, we need to know about each class of powder coating steel.


The surface characteristics are made up of oxides, hydrates, and salts that together form the metal’s composition.

There are contaminants, as well.  When you are dealing with steel, there may be contaminants such as surface carbons, dirt, bacteria, mildew, fungus, oils, lubricants, metal fines, non-metallic surface inclusions, rolled-in scale, large surface carbides, and corrosion products.

When you are working with zinc, you may encounter contaminants like oils, lubricants, dust, dirt, soil, corrosion products, and metal fines. Aluminum brings many of the same contaminants as zinc, with the addition of aluminum oxide.

Because there are so many different possible contaminants and many different types of metals, there is no single method of part preparation for powder coating that is suitable for every situation.

The method used for preparing a part for powder coating will vary based on the type of metal and the contaminants present.

Powder Coating Steel: Types of Steel to Coated

Steel is an alloy of carbon and iron. There are additional small amounts of other elements in steel, as well.  There are many different gauges of steel, each of which has different properties.


Hot & Cold Rolled Steel

Hot rolling is used to produce heavy gauges of steel.  Hot rolling is the first step in creating a steel slab.  The resulting surface has a layer of mill scale.  This scale often loosens during the manufacturing process.

For this reason, hot rolled steel that has not had the mill scale removed is not a good candidate for powder coating.  The coating does not adhere well.

The mill scale must be removed prior to coating using acid pickling or mechanical cleaning.  Welded areas on hot rolled steel must be removed through mechanical cleaning using a wire brush or sandblasting prior to coating.

Cold rolling steel produces thinner gauges of steel.  Cold rolled steel does not have mill scale and carbon dust on its surface like hot rolled steel, but it does have some oil that serves as a rust inhibitor.  It can be chemically cleaned to prepare it for powder coating.

High Strength Low Alloy Steels

High strength low alloy (HSLA) steels are an alloy blend that are used to obtain a better ratio of strength to weight.  They can usually be prepared using the same methods as carbon steels.

Surface oxidation can be removed by grit blasting.  When HSLA steel is blasted to white metal, some shadowing may occur.

This shadowing is not a problem, and powder coating can still be applied and achieve good adhesion.  However, some types of HSLA steel contain silicone.  The silicone can interfere with cleaning and coating.

Stainless Steel

Stainless steel does not contain many of the common surface contaminants as carbon steel.  Prior to coating, stainless steel should be cleaned to remove any dirt or surface oils it may have picked up while being handled.

Since stainless steel doesn’t react to environmental triggers like other metals, it usually does not have a protective coating.

It has a passive oxide layer that means that the chemicals that are used to clean carbon steel will not affect stainless steel.  Mechanical abrasion can be used to remove the oxide layer and create a rough surface that will adhere to powder coating.

Are you interested in having an item powder coated & apply powder coating steel?  Contact Byers Bush Powder Coating Inc.. We have been providing powder coating and sandblasting services in Toronto, Concord, Hamilton, Brampton, Oakville, Ontario for more than 40 years.

We are known for providing high-quality finishes and doing so with a quick turnaround time and excellent customer service. Our experienced and qualified team has the expertise that you need in order to achieve a perfect powder coated finish.

Before we coat your item, our team will inspect it.  They will check the condition of the item, and decide what needs to be done to prepare the item for powder coating.

Call Us Today

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