3668.     WESTGREN, A., AND LINGH, A. E.  [Crystal Structure of Iron and Steel.]  Ztschr. physik. Chem., vol. 98, 1921, pp. 181-210; Chem. Abs., vol. 15, 1921, p. 3812.

        Deals with an X-ray spectrographic investigation of the crystal structure of Fe and steel.  The results of Hull (abs. 1516) that the atoms of pure Fe at ordinary temperature (a-Fe) are arranged on a centered cubic lattice, have been confirmed.  At 800°-830° that is, within the so-called β-Fe interval, the atoms are grouped in the same way as in a-Fe.  Since allotropy of crystalline solids is synonymous with polymorphism, β-Fe cannot be regarded as a special modification of Fe.  In both austenite and pure Fe, which is stable at 1,000°, the crystals have a plane-centered cubic lattice.  This is also characteristic of γ-Fe, and constitutes a fundamental difference between a- and γ-Fe.  In martensite the Fe appears in the form of the a modification.  This is likewise the case in rapid-drawn steel of ordinary composition that has been hardened at 1,275°.