Laser Cladding of Tungsten Carbide | Advantages | Challenges

Importance of Tungsten Carbides

In applications like mining, and many marine applications, the tools are subjected to a very high amount of abrasion. For this, the tools must be very hard and must have high abrasion resistance. Carbides are suitable for this application as they have high abrasion resistance and are very hard. However, the problem with carbides is that they are very brittle. When subjected to high pressure, they can easily break.

For this, there is a solution. The tools are made up of base materials like high carbon steels, mild steels, etc. They are ductile, malleable and also much cheaper than carbides. These tools are made up of MS/ SS / High Carbon steels, and then given a coating of carbides like tungsten carbide.

Advantages of Laser Cladding of Tungsten Carbides:

• Hardness, high abrasion resistance and wear resistance of carbides
• Higher toughness of the base metal
• Solution is economical depending on the base material

Challenges of Laser Cladding of Tungsten Carbides:

Giving carbide layer to base metals also has some challenges.

• The carbide coating may undergo cracks.
• In marine applications, the salt water may penetrate the cracks in the carbide layer and come in contact with base material, and cause corrosion of base material reducing the life of the tool.

BUFFER LAYER

For this, a buffer layer of soft material like nickel (0.5 to 1 mm thickness)  is cladded over base material, and then the carbide layer is cladded over the buffer layer. This reduces the probability of cracks, and in marine applications, even though the corrosive salty sea water penetrates through cracks in the carbide layer, the buffer layer of nickel being corrosion resistant protects the base material from corrosion, thus increasing the life of the tool.

Tungsten Carbide Coating : The Tungsten carbide particles are mixed in a metal matrix consisting of Ni-Cr-B-Si (Nickel, chromium, boron, silicate) in powder form in a predefined ratio of weight. This powder mixture is then deposited on the customer part where hard facing is required.

Laser cladding technology offers a very robust , automated, low heat input process for cladding Tungsten carbide overlays.

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