The BrazeCoat process can be applied in two ways. The
BrazeCoat-M Process results in a thicker wear resistant coating, while the BrazeCoat-S process results in a
thin, smooth coating. Both are processed in Lund’s hydrogen atmosphere
furnace, and both result in coatings of extremely high tungsten carbide content by weight.
With the BrazeCoat-M
Process, flexible mats, consisting
of carbide powders and filler metal powders (e.g. NiCrBSi), bonded by a polymer binder, are cut into the appropriate shape
and placed onto the substrate. After preparation the assembly is heat treated in a furnace process at approx. 1100 °C
under the protective hydrogen atmosphere. The carbide layer is infiltrated by the molten filler metal and in the same operation
brazed to the substrate. In the BrazeCoat-M process the thickness of the resulting layers can be adjusted between 0.7 mm (0.028
in.) and 3 mm (0.12 in.) or even more. The final layer is conforms
to the contour of the part.
Typical applications for BrazeCoat M-layers can be found
where heavy abrasive wear or even a combination of abrasive and corrosive wear appears. Slurry pump housings, mixer blades
and extruder parts, all coated by the BrazeCoat-M process have resulted in significantly longer component lifetime under actual service conditions.
With the
BrazeCoat-S Process the surfaces of components are protected against severe wear by
spray depositing a carbide/hard facing alloy suspension, which is then heat
treated in the hydrogen atmosphere furnace. The thickness of the resulting layers can be adjusted between 0.05 mm (0.002
in.) and 0.5 mm (0.02 in.).
The coatings are well bonded and show a porosity of less than 1%. The surface as
coated is very smooth, and for most applications final machining is not necessary. Due to the high carbide content
of the coating layer, hardness values of over 65 HRC are obtained. Wear tests, under laboratory conditions as with components
under service conditions in the field, showed improved resistance against abrasive wear over nitrided, borided or thermally
sprayed layers.
The BrazeCoat-S Process has been applied successfully
to protect fan blower disks, housings and mill rotors, hydraulic cylinders or plungers and piston rods in hydraulic and
pneumatic application, where a severe wear attack is combined with the requirement for narrow tolerances.