- Description
Overlay Plate: Wear Resistance Mechanism of Hardfaced Weld Layers
Overlay plate (also called hardfaced plate or weld overlay wear plate) is a composite steel product that achieves high wear resistance by depositing a hard alloy layer onto a steel base plate through welding. Its excellent performance does not come from the base steel, but from the metallurgical structure of the overlay layer.
The wear resistance mechanism is mainly based on the interaction between hard carbides, alloy matrix, and surface stress behavior.
1. Hard Carbide Reinforcement Mechanism
| Element / Phase | Function in Wear Resistance |
|---|---|
| Chromium carbides (Cr7C3, Cr23C6) | Primary hard phase resisting abrasion |
| Carbon (C) | Forms carbide structures with chromium |
| Iron-based matrix | Supports and holds carbides in place |
| Alloying elements (Nb, Mo, V) | Refines carbide distribution and improves stability |
The hard carbides act like “micro cutting tools” that resist scratching and cutting from abrasive particles.
2. Two-Phase Composite Wear Structure
The overlay layer is a dual-phase structure:
- Hard phase: Carbides (high hardness, resist wear)
- Tough matrix: Metal binder (absorbs impact and holds structure)
This combination provides both hardness and limited toughness, which is essential for industrial wear conditions.
3. Abrasive Wear Resistance Mechanism
| Wear Type | How Overlay Layer Works |
|---|---|
| Sliding abrasion | Carbides resist cutting and micro-scratching |
| Particle erosion | Hard surface reduces material loss from impact particles |
| Friction wear | Reduces surface deformation and groove formation |
4. Stress Distribution and Crack Behavior
During welding, controlled micro-cracks may form on the surface:
- They help release residual stress
- They prevent large-scale fracture
- They do not reduce wear performance
This stress-relief behavior helps maintain long-term stability under heavy wear conditions.
5. Bonding Strength Mechanism
Overlay plates are not mechanically attached—they are metallurgically bonded.
- Strong fusion between overlay and base plate
- No delamination under normal working conditions
- Improved load transfer capability
6. Why Overlay Plates Last Longer Than Ordinary Steel
| Factor | Effect on Service Life |
|---|---|
| High surface hardness | Reduces material loss rate |
| Carbide reinforcement | Prevents cutting wear |
| Composite structure | Balances wear resistance and toughness |
| Controlled alloy design | Improves stability in harsh conditions |
7. Teda Ganghua Overlay Plate Supply Capability
As a professional wear-resistant steel supplier, Teda Ganghua provides high-performance overlay plates with optimized carbide structures for mining, cement, steel, and power industries. We focus on improving wear resistance through controlled alloy design and stable welding processes.
We also support customized cutting, fabrication, and wear system engineering based on real working environments.
Explore our wear-resistant steel products here:
Chromium Carbide Overlay Plate
Conclusion
The wear resistance of overlay plates comes from hard carbide reinforcement, composite dual-phase structure, and metallurgical bonding. These mechanisms work together to significantly reduce material loss under abrasion, making overlay plates one of the most effective industrial wear solutions.
