| 摘要 |
PURPOSE: A plasma spray coating method of hearth roll is provided to give superior thermal shock resistance to the hearth roll by forming a bond coat on the surface of the hearth roll and forming a top coat on the bond coat using plasma spray coating method, thereby increasing deposition efficiency and minimizing internal stress. CONSTITUTION: The plasma spray coating method of hearth roll is characterized in that a bond coat (12) is formed on the hearth roll (11) by spray-coating spraying powder having constituents of CoNiCrAlY on the surface of the hearth roll, and a top coat (13) is formed on the bond coat by spray-coating spraying powder in which Cr3C2-NiCr is mixed with CoNiCrAlY on the bond coat, wherein the bond coat is formed of a spraying material comprising 30 to 35 wt.% of Ni, 20 to 25 wt.% of Cr, 10 to 6 wt.% of Al, 1 to 0.1 wt.% of Y and a balance of Co, and wherein the top coat is formed of a spraying material in which a spraying material comprising 24.0 to 25.5 wt.% of Ni, 8.0 to 9.5 wt.% of C and a balance of Cr is mixed with a spraying material comprising 30 to 35 wt.% of Ni, 20 to 25 wt.% of Cr, 10 to 6 wt.% of Al, 1 to 0.1 wt.% of Y and a balance of Co. The plasma spray coating method of hearth roll comprises the processes of forming a bond coat (12) by spray-coating spraying powder of CoAl-Cr3C2 constituents on the surface of the hearth roll (11); forming a top coat (13) on the bond coat by spray-coating spraying powder of CoAl-Cr3C2Al2O3 constituents on the bond coat; and heating to fire the coated hearth roll at a temperature of 650±10 deg.C for 110 to 130 minutes.
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