The Process of Galvanizing Steel: How It Works

Galvanized steel is used in just about every industry and every application, from computer casings to playground equipment, and from cars and aircraft to street furniture. At Sherwood Steel, we understand that it needs to be strong and durable. And considering its ubiquity, there’s no surprise that the process of galvanizing steel is meticulous and thorough.

The conventional method of galvanizing steel is through the hot dip process. But before that can occur, there are some necessary steps to prepare the steel.

Surface Preparation

The preparation of the steel surface is vital to galvanizing. Any faults or inadequacies on the material will become apparent because the zinc won’t react with the surface, leaving problem areas uncoated.

  • Degreasing is the first step of surface preparation for galvanizing steel. A mild acid bath or hot alkaline solution will remove organic contaminants like paint, grease, dirt, and oil from the metal’s surface.
  • A heated solution of hydrochloric acid then removes rust from the surface in a process called pickling. This can also be accomplished by abrasive cleaning.
  • Finally, a solution of zinc ammonia chloride removes any remaining oxides and creates a protective layer on the steel.

The Zinc Bath

The true step of the galvanizing process is when the material is immersed in a bath of molten zinc which has been heated to 815-850 degrees Fahrenheit. While immersed in the kettle, the zinc reacts with the iron in the steel, forming a bonded layer which will protect the material and make it durable.

Inspection

Once the steel has been cooled and dried, it needs to be inspected for quality. The thickness of the coating and condition of the surface are carefully scrutinized, and various physical tests are performed to determine adherence, appearance, and thickness are implemented to access its quality.
All this happens before it comes to Sherwood Steel’s Philadelphia-area facility, so you can be confident that our galvanized steel is of the highest quality and strength, and meets all industry standards for use.

For more information or to purchase galvanized steel from Sherwood Steel, call us at 215-309-8309 or visit http://www.sherwoodsteelinc.com/.