Carbide Coatings for Exhaust Fans with HVAF
Kermetico HVAF equipment provides an effective way to protect exhaust fan impellers from abrasive wear. Kermetico HVAF thermal spray systems deposit ductile, high-bond wolfram carbide coatings as hard as 1,600+ HV300 and as thick as 3mm (0.120”). The gas impermeable HVAF coatings are superior to any other surfacing technology in dry or wet abrasion protection of exhausters.
The Abrasive Wear of Centrifugal Impellers
Centrifugal fans provide air for industrial processes like coal and lignite-fired power plants, cement, metal or woodchip manufacturing. Particles present in the air stream wear the fan surfaces.
This wear is induced both by very fine particles, for example, fumes, as well as by large particulate matter such as wood chips. Fan impeller blades are the most severely attacked components. Once they are worn-out, the resulting geometrical alteration can lead to dramatic efficiency drops. Furthermore, balance problems appear, affecting the service life of the ancillary equipment.
The resulting change in operational conditions increases energy and maintenance costs and leads to unplanned plant downtimes.
Advanced wear protection of equipment, as a preventative maintenance measure, reduces overall costs and diminishes the risk of unscheduled outages of exhaust equipment.
Thermal spray coating of a fan reduces severe wear, increases the fan productivity and prolongs intervals between planned repair cycles.
Kermetico HVAF tungsten carbide coatings are created for extreme abrasion, erosion and corrosion conditions where the abrasion resistance of regular steel or conventional abrasion-resistant coatings does not meet the need. The abrasion resistance of the Kermetico HVAF (tungsten) carbide is a hundred times better than that of regular steel, and many times better than weld overlays.
Kermetico HVAF and HVOF carbide abrasion resistant coatings lengthen the fan’s operational life and significantly reduce the wearing of the impeller and other fan components, which could lead to additional outages and premature repairs.
Surface Treatment to Protect Centrifugal Equipment from Corrosion and Wear
Carbide coatings deposited by using different high velocity technologies (HVOF, HVAF and Detonation), are extremely wear-resistant. Industry uses tungsten carbide in combination with cobalt, nickel or cobalt-chrome matrices preferably. The erosion and corrosion behavior of wolfram carbide coatings is a key element for the assessment of the coating application.
We use our Kermetico HVAF equipment to deposit tungsten carbide coatings that are wear resistant and tough enough to be effective at all angles of impingement.
We recommend WC-CoCr-bound powders because they exhibit the highest wear resistance coupled with adequate corrosion resistance in any environment except very high pH environments or hydrofluoric acid. Only 100 microns of our WCCoCr coating is gas-tight, protecting a base metal of a fan from corrosive agents as a barrier layer.
A Kermetico HVAF Ultra-Quality WC-CoCr Coating, Hardness 1,600 HV300
Kermetico's Multi-Purpose HVAF AK7 and AK5 are recommended for exhaust fans.
