Colmonoy® 88 Material Information

About Colmonoy^® 88

Colmonoy^® 88 is a hard surfacing alloy patented under the Wall Colmonoy Corporation. This alloy consists of 3% Boron, 0.08% Carbon, 15% Chrome, 3% Iron, 4% Silicon, 17% Tungsten with a balance of Nickel. The combination of complex borides and carbide with the Ni-Cr-B matrix offers excellent hardness (59-64 Rockwell C) and extends the service life of parts exposed to high-temperature abrasion, erosion, corrosion, galling and fretting.

Selection Criteria for Colmonoy^® 88 Coatings

Colmonoy^® 88 has applications in many different industries and is present in multiple forms including bare rods, powders, ingots, castings, etc. For thermal spray coating applications a powder form is applied for both strength and hardness requirements at elevated temperatures. Colmonoy^® 88 also has excellent resistance to abrasion, erosion, corrosion, pitting, galling and fretting.

Properties of Colmonoy^® 88 Coatings

• Excellent hardness due to carbide and boride forming elements (59-64 Rockwell C)
• Retains reasonable hardness at higher temperatures
• Good Strength
• Excellent resistance to wear
• Good resistance to hot oxidation, sulfidation and erosion
• Protective oxide layer of chromium oxide on the surface
• Excellent resistance to pitting corrosion due to high Ni content
• High bonding strength
• Dense coating

Potential Coating Benefits

• Colmonoy^® 88 coatings enhance the service life of the product.
• Coatings are very effective for wear protection.
• Spray coating technology is efficient and reliable.
• Good defense against a wide variety of surface attacks and damages.
• Good combination of metallurgical and mechanical properties.
• No expected loss of hard phases during coating development.

Disadvantages

• Due to fusing operation parts have to be able to withstand high temperatures (1950° F) without degrading

Uses and Applications

• Commonly used in spray and fuse applications.
• Plastic-extrusion screws, plastic-injection screws and in twin-barrel extruders where wear resistance is required.
• Triplex and duplex pump plungers, frac-pump plungers and thermowells.
• Power plant grate bars, hot-cyclone separators, superheater tubes & panels and boiler tubes.
• Ball valves, pump casings and pump sleeves.
• Mixing rotors and end plates.
• Slurry-pipe elbows, coal-discharge chutes and centrifugal scrolls.
• Wire-drawing capstans.

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