"Non-Fused Materials. Various non-fused materials have been used for
cavitation damage repairs. These include:
cavitation damage repairs. These include:
Epoxies
Ceramics
Metal spraying
Neoprene
Urethane
Ceramics
Metal spraying
Neoprene
Urethane
"The application of these materials is far from an exact science and the success
of this method of cavitation repair has generally not been good. The most
commonly used materials are:
of this method of cavitation repair has generally not been good. The most
commonly used materials are:
Belzona Ceramic Compound - Belzona R followed by an overcoat of
Belzona S
Belzona S
Devcon - either Plastic Steel Putty, Stainless Steel Putty, or Wear
Resistance Putty
Resistance Putty
"Plant owners may have other materials with which they have had success.
"Specific recommendations for application of non-fused materials must be obtained
from the material supplier and these should be closely followed. The major difficulty
with non-fused materials for cavitation pitting repair is achieving a satisfactory bond
to the parent material. In this regard, general recommendations are as follows:
from the material supplier and these should be closely followed. The major difficulty
with non-fused materials for cavitation pitting repair is achieving a satisfactory bond
to the parent material. In this regard, general recommendations are as follows:
Ensure surface to which the material is to be applied is properly cleaned.
This usually involves blast cleaning, followed by solvent cleaning as
necessary.
This usually involves blast cleaning, followed by solvent cleaning as
necessary.
Maintain temperature and humidity levels in the turbine area within
recommended limits.
recommended limits.
A rough surface is best for bonding of non-fused material to the parent
metal; therefore, roughening the area with a grinding wheel is usually
beneficial.
metal; therefore, roughening the area with a grinding wheel is usually
beneficial.
Allow sufficient cure time after the material has been applied, prior to
rewatering of the unit.
rewatering of the unit.
"The recommendations for final surface profile are as presented for weld repairs.
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