| 摘要 |
PURPOSE:To enhance the corrosion resistance of carbon steel or low Cr steel at high temp. by diffusing Cr in the steel by cementation by a powder packing method using powder contg. Ni and Cr in a prescribed ratio. CONSTITUTION:Powder contg. Ni and Cr in Ni/Cr=1-15 is mixed with Al2O3 powder and NH4Cl powder. Carbon steel or Cr steel contg. <=25% Cr is embedded in the mixed powder. While feeding gaseous H2, the powder is heated to a high temp. such as 1,100-1,200 deg.C to diffuse Cr in the steel by cementation. The resulting steel has corrosion resistance at high temp. and is suitable for a boiler tube. |
