coil coating process, AZZ

Coil Coating Process

Engineered for consistency, speed, and efficiency

The coil coating process is one of the most advanced and efficient methods for applying protective and decorative coatings to steel and aluminum coils before fabrication. Operating in a continuous, highly controlled environment, the process delivers exceptional consistency, durability, operational efficiency, and long-term product performance across a wide range of industries and applications.

Click the Image Hotspots to Learn About Our Process

coil coating process, AZZ

What is coil coating

The coil coating process handles metal coils up to 72 inches wide at speeds approaching 700 feet per minute. Both sides of the metal are cleaned, treated, primed, top-coated, and cured before being recoiled for shipment and downstream manufacturing. This continuous automated coil processing helps ensure precise coating application, improved quality control, enhanced corrosion resistance, and consistent appearance retention from start to finish.

Compared to traditional post-paint methods, coil coating provides significant cost, quality, and environmental advantages. The process reduces waste, improves paint utilization, streamlines manufacturing workflows, and supports greater production efficiency while delivering durable, high-performance finishes.

Coil coating is also recognized as one of the industry’s most sustainable finishing methods, operating as a closed loop system with more than 98% VOC capture and conversion to fuel. In European markets, the finished product is commonly referred to as “prepainted” or “precoated” metal.

coil coating process, AZZ

Entry End

Uncoiler

Metal coils, up to 60,000 pounds, are received and undergo visual inspection before moving to the uncoiler for unwinding.

Coil Stitch

At this stage, previous and next coil ends are mechanically joined, ensuring continuous feed in the coil coating line.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ

Entry Accumulator

The accumulator is a structure that adjusts up and down to store material, which makes continuous operation of the coil coating process possible. This accumulation will continue to feed the coil coating processes while the entry end has stopped for the stitching process. As much as 750 feet of metal can be collected.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ

Cleaning & Pretreating

The cleaning and pretreating section of the coil coating process focuses on preparing the metal for painting. During the cleaning stage, dirt, debris, and oils are removed from the metal strip. From there, the metal enters the pretreatment section and/or a chemical coater whereby chemicals are applied to facilitate paint adhesion and enhance corrosion resistance.

Dried-In-Place

In this stage a chemical that provides enhanced corrosion performance is applied. This treatment can be chrome free if required.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ

Prime Coat

During this stage, the strip enters the prime coat station whereby a primer is applied to the clean and treated metal. After the primer is applied, the metal strip travels through a thermal oven for curing. Primers are used to aid in paint adhesion, improve corrosion performance and enhance aesthetic and functional attributes of the topcoat.

S Wrap Coater

The S wrap coater design allows for primers and paints to be applied to the top and back side of the metal strip simultaneously in one continuous pass.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ

Topcoat

After the primer is applied and cured, then the metal strip enters the finish coat station where a topcoat is applied. Topcoats provide color, corrosion resistance, durability, flexibility and any other required physical properties. Like primers, the topcoat is cured using thermal cure ovens.

Oven

Coil coating ovens can range from 130 feet to 160 feet and will cure the coatings in 13 to 20 seconds.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ

Exit Accumulator

Like the Entry Accumulator, the Exit Accumulator adjusts up and down to store metal while the recoiler is unloading a completed coil.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ

Exit End (Recoiler)

Once the metal is cleaned, treated, and painted, the strip is rewound into a coil size prescribed by the customer. From there, the coil is removed from the line and packaged for shipment or additional processing.

coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ
coil coating process, AZZ