Saldatura sovrapposta al carburo di cromo

Chromium carbide overlay welding is a hardfacing process used to create extremely wear-resistant steel plates and components. By welding a chromium-rich alloy layer onto a steel base plate, a surface with elevata durezza, resistenza all'abrasione, e lunga durata is formed.
This technology is widely used in minerario, cemento, centrali elettriche, acciaierie, e sistemi di movimentazione di materiali sfusi.

Structure of Chromium Carbide Overlay Plate

A chromium carbide overlay plate is a composite welding steel made of two layers:

The overlay contains carburi di cromo (Cr₇C₃ and Cr₂₃C₆), which are responsible for its exceptional hardness.

Chromium Carbide Overlay Welding Process

1. Preparazione della piastra di base

The carbon steel base plate is cleaned to remove:

• Rust

• Olio

• Scale

Questo garantisce strong metallurgical bonding durante la saldatura.

2. Hardfacing Alloy Welding

A special chromium carbide welding wire or flux-cored wire is used.
The overlay is deposited by automated welding processes such as:

• Saldatura ad arco con filo animato (FCAW)

• Saldatura ad arco sommerso (SEGA)

• Saldatura ad arco aperto (OAW)

These processes allow precise control of alloy composition and layer thickness.

3. Formation of Carbide Microstructure

Durante la saldatura:

• Molten alloy solidifies on the base steel

• Chromium carbides crystallize inside the overlay layer

• These hard carbides are embedded in a tough alloy matrix

This creates a surface hardness of HRC 55–65.

4. Stress Relief Crack Pattern

After cooling, a network of fine, evenly spaced cracks appears in the overlay.
These cracks:

• Release thermal stress

• Prevent large structural cracking

• Do not affect wear resistance

Questo è un designed feature, not a defect.

5. Cutting and Forming

The finished overlay plate is cut using:

• Taglio al plasma

• Taglio laser

• Water-jet cutting

It can then be formed into:

• Wear liners

• Chute plates

• Bending segments

• Pipes and conveyor components

Why Chromium Carbide Overlay Welding Is Used

This welding process provides:

• Extremely high abrasion resistance

• Strong metallurgical bonding

• Customizable overlay thickness

• Lower cost than solid wear-resistant alloy steel

• Easy repair by re-welding

Applicazioni tipiche

Chromium carbide overlay plates are used in:

• Attrezzature per miniere e cave

• Scivoli e tramogge per impianti di cemento

• Sistemi di movimentazione del carbone

• Power plant ash conveyors

• Steel mill material handling

Questi ambienti coinvolgono severe sliding abrasion, impatto, and particle erosion.