A STUDY OF THE MICROSTRUCTURE AND PROPERTIES OF CONTINUOUS-CASTING RARE-EARTH DUCTILE IRON PIPES

Continuous casting procedures are simpler than centrifugal casting. Co ntinuous casting rare earth ductile iron can be obtained by adding REM gSiFe. This paper researches the effect of elements on structures and properties of rare earth ductile iron pipes. Methods for improving the properties of rare earth ductile iron pipes are discussed. The streng th and elongation of the pipe are 515-485 MPa and 2.5-2.7% without hea t treatment or 440-425 MPa and 7-16% with heat treatment. The microstr ucture of the matrix of continuous casting rare earth ductile iron pip es are ferrite or pearlite or ferrite plus pearlite. In China, continu ous casting rare earth ductile iron pipes have been produced successfu lly. and used in different fields.