Thermal Spray / Hard Surfacing

Thermal coatings are a highly cost-effective way to add superior performance qualities to calender rolls. The hard surfacing process involves heating a material in powder form to a semi-molten state. The material is propelled using a high velocity combustion process to deposit it, creating a surface structure on a given substrate, in this case, the calender roll face.

SHW uses the High Pressure/High Velocity Oxygen Fuel (HP/HVOF) process, which has been proven to be the best for spraying high-density, high hardness, and high bond strength carbides and metallic materials. All materials sprayed with HP/HVOF are in neutral-to-compressive stresses. The coating grips the surface resulting in extremely high bond strength. We have this state-of-the-art process right in our one-stop roll service manufacturing facility.
Hard surfacing will provide up to 300% longer intervals between grinds and a potential for a hardness of HV1100 Vickers which is nearly twice that of chilled iron! Hard surface coatings are customized to your mill. The coating formulation and application processes are tailored to the precise operational needs of the roll. The most popular coatings used are:

• Tungsten Carbide Cobalt (83% Tungsten Carbide, 17% Cobalt)
• Chrome Carbide Nickel Chrome (75% Chrome Carbide, 25% Nickel Chrome)
• Tungsten Carbide Chrome Nickel (73% Tungsten Carbide, 27% Chrome Nickel)

The benefits of such a process include:

• Superior Wear and Abrasion Resistance
• Corrosion Prevention
• Increased Calender Up-Time
• Improved Paper Quality and Finish
• Improved Regrind Cycles
• Longer Lasting Roll Profiles
• Surface Finishes up to 2 Ra
• We have sprayed hundreds of rolls with no mechanical bond failure