Piatto rivestito

UN Piatto rivestito is a type of composite steel plate that combines a tough base metal with a wear-resistant overlay.
Mentre carburo di cromo (Cr₇C₃ / Cr₃C₂) is the most commonly used overlay material, modern industrial applications require a variety of wear-resistant alloys depending on abrasion type, condizioni di impatto, temperatura, e corrosione.

This article explores alternative materials suitable for producing high-performance wear-resistant clad plates.

1. Carburo di tungsteno (wc)

Rivestimento in carburo di tungsteno fornisce durezza estrema and is ideal for high-abrasion environments.

• Durezza: 68–75HRC (≈1500–1800 HV)

• Meccanismo di usura: Grain fracture and erosion-resistant binder

• Best For: Slurry handling, dragaggio, drilling tools, sand-laden conveyors

• Pros: Maximum abrasion resistance, long wear life

• Cons: Brittle under heavy impact, higher cost

2. Carburo di niobio (NbC)

Niobium carbide is used in complex carbide overlays to improve toughness while maintaining hardness.

• Durezza: 60–68HRC

• Meccanismo di usura: Abrasion-resistant carbide particles embedded in steel matrix

• Best For: Benne da miniera, frantoi, cement screw conveyors

• Pros: Eccellente resistenza agli urti, resists cracking under heavy load

• Cons: Slightly lower abrasion resistance than pure tungsten carbide

3. Vanadium Carbide (V.C)

Vanadium carbide creates fine, dense carbides that improve surface wear resistance.

• Durezza: 58–64 HRC

• Meccanismo di usura: Micro-abrasion resistance, fine carbide distribution

• Best For: Viti per cemento, sand handling equipment, general conveyors

• Pros: Balanced wear and toughness, reduces micro-cracking

• Cons: Moderate hardness compared to WC

4. Molybdenum-Alloyed Carbides (Cr–Mo–C or MoC)

Adding molibdeno migliora resistenza al calore and reduces oxidation of the overlay.

• Durezza: 55–62 HRC

• Meccanismo di usura: Sliding abrasion at elevated temperatures

• Best For: Clinker hoppers, high-temperature industrial processes

• Pros: Stable hardness under heat, good wear resistance

• Cons: Slightly lower hardness than pure Cr carbide

5. Complex Multi-Alloy Carbides

Modern wear-resistant clad plates often combine Cr, N.B, V, Mo, W carbides in a single overlay to achieve:

• High abrasion and impact resistance

• Thermal stability (fino a 850 °C)

• Corrosion resistance in harsh environments

Example Composition: Fe–Cr–Nb–V–Mo–C

• Durezza: 60–68HRC

• Applicazioni: Estrazione, cement clinker handling, frantoi, scivoli di trasferimento, trasportatori pesanti

6. Alternative Wear-Resistant Alloys

Apart from carbides, some clad plates use:

7. Choosing the Right Material

When selecting an overlay material for a clad plate, considerare:

1. Tipo di usura – sliding abrasion, impatto, slurry erosion

2. Operating temperature – high-temperature service favors Mo or Cr–Mo alloys

3. Corrosion conditions – Ni-based or stainless overlays

4. Cost vs performance – WC offers maximum wear life but higher cost; complex Cr–Nb–V alloys balance wear and toughness

8. Riepilogo