2832.     ROBERTS, E. C.  Precementitic Carbides in Tempered Marensite.  Jour. Metals, vol. 188, 1950, Trans., p. 1210.

        The 3d stage of tempering quenched steel is the development of cementite from an intermediate, which makes its appearance in the 1st stage.  This is not a transition precipitate but a distinct entity with no coherence existing between the carbide and the matrix.  It forms faster in quenched martensite than does cementite, and its growth to larger particle size than early Fe3C must mean that the latter grows as a result of a competitive process.