MICROSTRUCTURE OF IRON-NICKEL ALLOY PRODUCED BY CENTRIFUGAL-SHS PROCESS

The microstructure and composition distribution of the iron-nickel alloy lined layer in a composite steel pipe produced by centrifugal-SHS process were investigated. The results showed that a martensitic transition region has been found between the iron-nickel layer and carbon steel matrix. A composition gradient of alloying elements exists in the iron-nickel alloy layer in the radial direction of the composite pipe. The alloying element contents in the lined layer are higher near the inner surface than near the outside surface. The intermetallic compounds AlNi₃ and AlNi precipitate in the iron-nickel alloy.