A Ni-Cr-Mo alloy, Alloy N06022 which contains 22wt.%Cr and 13wt.%Mo was investigated to evaluate the alloy's hot corrosion resistance, especially focused on its use for superheater tubes in waste- to-energy plants. Hot corrosion tests were performed at 550°C using a synthetic ash which contained equivalent amounts of NaCI, KC1 and NazSO 4. The results indicated Alloy N06022 had the desirable corrosion resistance for use as a superheater tube. To suppress the volume of the relatively expensive Alloy N06022,a Alloy N06022/Type 304 clad tube was proposed. The clad tube was produced by the helical rolling method and consisted of a Alloy N06022 outer tube and a Type 304 inner tube. Optical microscopy revealed a normal wrought microstructure was obtained. Moreover the interface between the outer and inner tube had desirable
strength. Hence, it was concluded that a Alloy N06022/Type 304 clad tube is an attractive component for superheater tube applications.
Keyword: Ni-Cr-Mo alloy, hot corrosion, waste-to-energy, clad tube, boiler tubing, waste incinerator, corrosion-resitant material