Production manner null of the boiler heat exchanger tube and the boiler heat exchanger tube which is superior in the inside of pipe surface deposit adhesion

摘要

PROBLEM TO BE SOLVED: To provide thermal spraying technology of suppressing the formation of deposits caused by boiler water generated at the part of the inside face of a boiler heat exchanger tube and the conversion of a tube material into oxidized scale caused by superheated steam and to provide sprayed coating film. ;SOLUTION: On the external heating surface to be contacted with a combustion gas in a boiler heat exchanger tube, porous sprayed coating film 32 is formed by using metal-alloy having oxidation resistance and high temp. corrosion-resistance more excellent than those of a heat exchanger tube material, oxide ceramic and oxide cermat, and the insides of the opening pores 33 of the porous sprayed coating film are impregnated and coated with solid inorganic sintered fine particles 35 consisting essentially of vanadium compounds and sulfur compounds, which is solidified at a high m.p., so that thermal shielding function is imparted thereto to prevent the excessive thermal flow rate to the heat exchanger tube.;COPYRIGHT: (C)1998,JPO