Lb chromium plating co1/13/2024 ![]() Kermetico HVAF WC-Co Coating Properties Featureīond strength of a tungsten carbide coating to carbon steel It also reduces the production cost due to higher spray rates achieved and use of air instead of pure oxygen.Ī distinguishing feature of the Kermetico HVAF process is that spray particles are heated but preferably not fused during spraying. With the HVAF combustion temperature below 2,000 oC (3,632☏), the surface temperature of Co-, Ni- and Fe-alloy particles usually remain near their melting point.ĭepositing WC-Co coatings by the Kermetico HVAF spraying process eliminates WC coating embrittlement and improves its hardness and density. Kermetico High-Velocity Air Fuel (HVAF) systems use gas fuel and compressed air for combustion at substantially lower temperatures and produce higher velocities than HVOF coating systems. This results in coating embrittlement and subsequent reduction of its service lifetime in conditions of abrasive and erosive wear. The decomposition of WC-Co coatings is directly related to a high combustion temperature, usually more than 3,000 oC (5,432☏), as well as the presence of oxygen in HVOF combustion products. These tungsten carbide coatings af steel can be used for abrasion-resistant coatings in dry, non-corrosive environments.Īlthough HVOF technology is frequently used for WC coating applications noticeable material oxidation and WC decomposition still occur during HVOF deposition. We recommend chromium carbide coatings for higher temperature applications.Ĭoatings that contain tungsten carbide protect substrates from the negative effects of fretting, abrasive grains, particle erosion and dynamic contact with hard surfaces. The tungsten carbide WC-12Co coatings are resistant to sliding wear, impact, abrasion and fretting at temperatures up to 510☌ (950 ☏), preferably in non-corrosive media. WC-12Co thermal spray coatings are usually harder compared to coatings of WC-17Co as a result of higher tungsten carbide levels in the coating. The Properties of HVAF WC-Co Tungsten Carbide Coatings on Steel Powders are available where cobalt is replaced with nickel. HVAF and HVOF Tungsten carbide coatings are sprayed with WC-Co agglomerated and sintered powder Nominal composition Low-Stress AbrasionĪbrasive wear occurs when hard particles are compressed with normal pressure against the surface of a metal, causing material removal.Tungsten Carbide WC-Co 88/12 Feedstock Properties (13.6 kg) using a 9 inch (229 mm) diameter rubber wheel and dry sand. Tested for 6000 revolutions at a load of 30 lb. The test allows comparison of wear-resistant materials by their volume loss in cubic millimeters, with materials of higher wear resistance showing lower volume loss. ![]() The ASTM G65 test simulates sliding abrasion conditions under moderate pressure, using dry sand metered between a rubber wheel and a block coupon of the material being evaluated. The wear rate is significantly reduced by hard micro constituents within the surface microstructure (embedded carbides for example). Low stress abrasion rates are directly proportional to the sliding distance and the load on the particles or protuberances. The operating forces must be low enough to prevent crushing the abradant. The low stress qualifier means that the abradant is imposed on the surface with relatively low normal forces. Grinding with a surface grinder can be a controlled form of low stress abrasion. Surfaces subjected to low stress abrasion show that material has been removed by hard, sharp particles or other hard, sharp surfaces plowing material out in the furrows.
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