Acciaio con riporto duro
IL hardfacing layer in hardfacing steel is produced through controlled overlay welding, using methods such as SEGA, FCAW, SMAW, or PTA.
By combining a hard, wear-resistant overlay con a base in acciaio resistente, hardfacing steel delivers maximum protection in extreme wear and impact environments, rendendolo ideale per minerario, cemento, energia, e applicazioni di movimentazione dei materiali.
- Descrizione
Hardfacing steel refers to steel components that have been coated with a hard, strato resistente all'usura through overlay welding.
IL hardfacing layer dramatically increases the abrasione, impatto, and erosion resistance of industrial parts, extending service life in minerario, cemento, energia, e applicazioni di movimentazione dei materiali.
Hardfacing Layer Structure
A typical hardfaced steel component has two main layers:
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Overlay Layer (Strato di rivestimento duro)
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Made of high-alloy steel, carburo di cromo, or cobalt-based alloys.
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Durezza: 50–65 HRC depending on the material.
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Funzione: Protects against sliding, impatto, and erosive wear.
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Strato di acciaio di base
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Generalmente mild steel (Q235), AR/NM wear steel, or structural steel.
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Provides tenacità, resistenza agli urti, e supporto strutturale.
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Hardfacing Welding Processes
Several welding techniques are used to deposit the hardfacing layer:
| Processo | Descrizione | Vantaggi |
|---|---|---|
| Saldatura ad arco sommerso (SEGA) | Large-scale welding with chromium carbide or hardfacing wires | High deposition rate, uniform layer thickness |
| Saldatura ad arco con filo animato (FCAW) | Uses flux-cored wires with hard particles | Flexible, suitable for medium and small parts |
| Saldatura ad arco di metallo schermato (SMAW) | Manual welding with hardfacing rods | Simple, ideal for repairs or field work |
| Plasma Transferred Arc (PTA) | High-energy plasma weld deposits powder overlay | Durezza molto elevata, minimal dilution, Eccellente resistenza all'usura |
Key Considerations in Hardfacing
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Spessore della sovrapposizione
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Typically 3–20 mm depending on wear conditions.
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Multi-pass welding may be used to build up the desired thickness.
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Preheating & Interpass Temperature
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Thick steel components may require preheating (150–250°C) per evitare rotture.
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Interpass temperature control ensures uniform hardness and minimal residual stress.
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Dilution Control
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Maintaining low dilution (≤10–15%) between the overlay and base steel is critical to preserve hardness.
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Trattamento Termico Post Saldatura
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Stress relief at 150–200°C may be applied.
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Riduce residual stresses and ensures dimensional stability.
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Surface Finishing
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Grinding or shot blasting removes weld spatter and uneven surfaces.
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Garantisce consistent wear resistance and smooth operation.
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Typical Applications of Hardfacing Steel
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Estrazione: Fodere del frantoio, bucket edges, hammer plates
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Cemento & Concrete: Slurry chutes, pale del miscelatore, screw conveyors
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Power Plants: Coal chutes, ash handling equipment
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Riciclaggio & Gestione del materiale: Trituratori, impact surfaces, fodere per trasportatori
Advantages of Hardfacing Layer
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Extreme Wear Resistance: Protects equipment from sliding and impact abrasion
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Extended Service Life: Reduces downtime and maintenance costs
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Customized Overlay: Thickness and alloy composition tailored to operating conditions
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Resistenza all'impatto: Steel base absorbs shocks while the overlay resists wear
