In order to improve the service life of 20 G high pressure boiler tube

the melting-solidified layer of Inconel625

Mo-free Inconel625 and Alloy686 nickel-base alloy powder was prepared on the surface of 20 G steel plate by laser melting solidification. Effects of nickel-based alloys on microstructure

hardness

tensile strength and high temperature corrosion resistance of laser melting-solidified layer at 550 ℃ were investigated. The results indicate that the grain size of Inconel625 is inclined to concentrate to <001> direction

followed by the grain of Mo-free Inconel625. The grain size of Alloy686 is partial inclined to<101> direction

however

the primary direction is <001> direction with homogeneous grain.The hardness

tensile strength and corrosion resistance of Alloy686 are optimal

while the plastic toughness is the worst

where the elongation is only 10.8%. After overall consideration

melting-solidified layer of Inconel625 is most suitable for the corrosion resistant layer of boiler tube.