What Is a CCO Wear Plate? Chrome Carbide Overlay Explained

For industrial operations—from mining and construction to material handling and cement production—equipment wear is a costly, ongoing challenge. Unplanned downtime, frequent part replacements, and rising maintenance costs eat into profitability, especially in environments where machinery faces constant abrasion, impact, and high temperatures. Enter the CCO wear plate: a specialized solution designed to protect critical equipment and extend its service life. But what exactly is a CCO wear plate, and how does chrome carbide overlay (CCO) deliver unmatched wear resistance? This guide breaks down the basics, benefits, applications, and key details to help you decide if CCO wear plates are the right fit for your operation.

What Is a CCO Wear Plate?

A CCO wear plate—short for Chrome Carbide Overlay wear plate—is a bimetallic composite plate consisting of two key layers: a tough, ductile steel base and a hard, wear-resistant chrome carbide overlay layer. The two layers are fused together through advanced welding processes (such as submerged arc welding, open arc welding, or plasma transferred arc welding) to create a metallurgically bonded product that combines the best of both materials: the strength and impact resistance of the steel base, and the extreme abrasion resistance of the chrome carbide overlay.

Unlike traditional wear-resistant steels, CCO wear plates are engineered to withstand severe abrasion, fretting, cavitation, and particle erosion—even in high-temperature environments (up to 1100 °F) and moderate impact conditions. The chrome carbide overlay, which makes up the surface layer, is rich in chromium (25–35%) and carbon (3.5–5.0%), forming a microstructure of primary Cr₇C₃ carbides embedded in a carbide-austenite eutectic matrix. These carbides are what give CCO plates their exceptional hardness, typically ranging from 58–65 HRC (Rockwell Hardness Scale)—harder than most abrasives encountered in industrial settings.

How Is Chrome Carbide Overlay (CCO) Applied?

The chrome carbide overlay is applied to the steel base using specialized welding techniques, ensuring a strong, seamless bond that prevents delamination (separation of the layers) during use. The most common methods include:

• Submerged Arc Welding (SAW): Ideal for large-scale production, this method offers high deposition rates and consistent overlay thickness, with welding channels running along the length of the plate. It produces a uniform, high-quality overlay with minimal defects.
• Open Arc Welding: More flexible for small-scale projects or repairs, this method creates welding channels along the width of the plate and is suitable for custom sizes or on-site applications.
• Plasma Transferred Arc (PTA) Welding: Delivers a uniform overlay with low dilution, ensuring consistent hardness and wear resistance across the entire plate surface.

After welding, the overlay may undergo post-weld heat treatment (150–200 °C) to reduce residual stress and prevent cracking, followed by shot blasting or grinding to create a smooth, uniform surface that ensures consistent wear and material flow. A key feature of CCO overlays is the presence of properly spaced hairline cracks—these are a natural, beneficial phenomenon that propagate through the overlay but stop at the fusion line, preventing further damage to the plate.

Key Features & Benefits of CCO Wear Plates

CCO wear plates offer a range of advantages over traditional wear-resistant materials (such as AR400/AR500 steel, rubber liners, or ceramic tiles), making them a cost-effective solution for industrial applications. Here are the top benefits:

1. Exceptional Abrasion Resistance

With a hardness of 58–65 HRC and a microstructure rich in Cr₇C₃ carbides (making up over 35% of the overlay), CCO plates resist sliding abrasion, particle erosion, and fretting far better than standard steels. This translates to longer service life—often 2–3 times longer than traditional wear plates—reducing the frequency of replacements.

2. Balance of Hardness & Toughness

The bimetallic design is critical: the chrome carbide overlay provides extreme hardness, while the mild steel or low-alloy steel base (typically Q235, S355, or AR400) offers ductility and impact resistance. This balance means CCO plates can withstand moderate impact without cracking or breaking—unlike brittle materials like ceramics, which are prone to shattering under impact.

3. Cost-Effective & Low Maintenance

While CCO wear plates may have a higher upfront cost than standard steels, their extended service life and reduced maintenance needs make them more cost-effective over time. Fewer replacements mean less unplanned downtime, lower labor costs, and reduced inventory of spare parts—all of which boost operational efficiency and profitability.

4. Customizable for Specific Applications

CCO wear plates can be tailored to meet the unique needs of your operation. Overlay thickness (3–20 mm) and base thickness (6–50 mm) can be adjusted, and plates can be cut, welded, drilled, or formed (perpendicular to the weld pass direction) to fit specific equipment. Custom sizes, studs, or holes are also available upon request.

5. High-Temperature Resistance

CCO plates perform reliably in high-temperature environments (up to 1100 °F), making them suitable for applications like cement kilns, incinerators, and high-temperature chutes—where other wear materials may degrade quickly.

Common Applications of CCO Wear Plates

CCO wear plates are used across industries where equipment is exposed to severe abrasion and moderate impact. Some of the most common applications include:

• Mining: Crusher liners, hammer plates, hoppers, chutes, conveyor liners, haul truck bed liners, and feeder plates. CCO plates protect mining equipment from abrasive rocks, ore, and sand, extending service life and reducing downtime.
• Material Handling: Conveyor systems, skirt boards, chutes, and hoppers for transporting abrasive materials like coal, gravel, and aggregates. The smooth overlay ensures consistent material flow while resisting wear.
• Cement & Concrete: Kiln shells, preheater towers, chutes, and mill liners. CCO plates withstand the high temperatures and abrasive materials (clay, limestone) in cement production.
• Construction: Excavator buckets, bulldozer blades, and crusher components. The impact resistance and abrasion resistance of CCO plates make them ideal for heavy-duty construction applications.
• Power Generation: Boiler chutes, ash handling systems, and coal pulverizers. CCO plates protect equipment from abrasive ash and coal particles, reducing maintenance costs and improving reliability.

CCO Wear Plates vs. Traditional Wear Materials

To help you understand why CCO wear plates are a superior choice, here’s a quick comparison with common alternatives:

• AR400/AR500 Steel: Less hard (40–50 HRC) than CCO plates, so it wears faster in severe abrasion environments. Requires more frequent replacements and higher long-term costs.
• Ceramic Tiles: Hard but brittle—prone to cracking under impact. Difficult to install and repair, and less flexible for custom applications.
• Rubber Liners: Good for impact but poor in high-temperature environments and less resistant to sharp abrasives. Degrades quickly in harsh industrial settings.

How to Choose the Right CCO Wear Plate

When selecting a CCO wear plate for your application, consider the following factors:

1. Abrasion Severity: For severe abrasion (e.g., mining crushers), choose a thicker overlay (8–15 mm) with higher hardness (62–65 HRC). For light to moderate abrasion (e.g., conveyor chutes), a thinner overlay (3–6 mm) with 58–60 HRC is sufficient.
2. Impact Level: If your application involves moderate impact (e.g., hammer plates), opt for a ductile base material (like S355 or AR400) to absorb impact without cracking.
3. Temperature: For high-temperature applications (above 500 °F), ensure the CCO plate is rated for your operating temperature (up to 1100 °F) and has undergone proper heat treatment.
4. Customization Needs: Work with a supplier who can provide custom sizes, thicknesses, and fabrications (cutting, welding, drilling) to fit your specific equipment.