The cause of scale forming in caustic soda aqueous evaporation, inefficiency of heat transfer and containing caustic in evaporative condensing liquid has been discussed.

By the end of 1979, We had produced the full scale forming die of the composite rotor blades of Y-2 type helicopter. The results of the NC machining show that this method is successful.

Ion exchange softening method is to use a certain scale forming ions in the ion exchanger, will be easy to generate the scale of calcium and magnesium ion in water, making water softening.