JOU RN AL 



OF THE 



NEW-YORK MICROSCOPICAL SOCIETY, 



Vol. VIII. JULY, 189;^. No. 3. 



STRUCTURE IN STEEL. 



ANNUAL ADDRESS OF THE PRESIDENT, P. H. DUDLEY. 

 (Read January si/i, i8gi.) 



Steel being an inorganic compound, the fact is overlooked that 

 when molten the enormous forces of crystallization are only held 

 in check by the intense heat, and, as the steel cools, more or less 

 structure is produced. 



Conditions which would affect the fineness or coarseness of tex- 

 ture in rail steel were given in my previous paper upon the same 



Explaiiattou of Plate 32. 



Fig. 1 is from the e.Kterior surface of a 50 carbon Bessemer rail ingot. The xyhite 

 lines enclosing the mineral aggregates, in this case, indicate more strongly the poly- 

 hedral than the columnar structure of the mgot. — Fia. 2 is from a .03 nickel armor 

 plate ingot. The polygonal structure is large, from one twentieth to one-tenth of an 

 inch in diameter. The juaction of three polygons i.^ shown near the centre of the figure. 

 The carbide of iron (?) is distributed in thin larainse, a small amownt of the charcoal, 

 work, and heat treatment rendering the steel homogeneous and exceedingly tough.— 

 Fig. 3 is from fluid, compressed, open-hearth steel, after the first hydraulic forging. 

 The carbide of iron is well distributed, though it has not reached the homogeneous con- 

 dition it will have after further forging and heat treatment.— Figs. 4, 5, and 6 are from a 

 .26 carbon Bessemer steel rail, from the Boston & Albany Railroad, after ten years' 

 service. Fig. 6 shows the structure in the head of the rail, the polygons being nearly 

 as coarse as in the structure of Fig. 1. The whitje lines show the distribution of the 

 carbide of iron, while the interior portions of the aggregates are much softer (?), and 

 break down near the upper surface of the rails, from the load of the passing wheels, as 

 shown in Fig. 4, and then flow off to bhe side of the rail, as showTi in Fig. 5, large pieces 

 eventually becoming detached. The structure of the surface of the rail is broken down 

 for one-twentieth of an inch in depth, the rail having lost three fourths of an inch in 

 height in ten years' service. The metal in flowing soon reaches its percentage of eloH- 

 gation, and cracks, or shears from the metal underneath. (See Figs. 4, 5.)— Fig. T is 

 from a rail made in 1866, and was in service over twenty years, under heavy traffic. The 

 structure is very fine, and the loads upon the wheels have affected the metal but little 

 over one-hundredth of an inch in depth from the surface.— Fig. 8 is from a .CO carbon 

 rail head, the structure hardly traceable, fine, and dense. 



