.~>90 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



had angular outlines. In the light from a carbon arc they appeared 

 bright pink in colour. As it was not possible to isolate sufficient of the 

 substance for analysis, various compounds of titanium were incorporated 

 with untreated rail steel, melted in a vacuum, until a substance was 

 found which gave inclusions having the same microscopic characteristics 

 as the pink spots. Titanium sulphide and carbide did not give pink 

 inclusions. Titanium nitride gave inclusions precisely similar to those 

 found in the rail steel, and the same result was obtained when the ex- 

 periment was repeated with special precautions to exclude alumina, thus 

 indicating that the pink inclusions were not alumina coloured with 

 titanium. The author concludes that the pink inclusions are titanium 

 nitride, possibly containing small amounts of iron or carbon, but no 

 alumina. 



Structure of Manganese Steel.* — In the course of an investigation 

 upon the magnetic and mechanical properties of steel containing 12 p.c. 

 manganese and 1'25 p.c. carbon, R. A. Hadfield and B. Hopkinson 

 have examined specimens microscopically. Quenched from 1000° C. 

 the alloy had a fine-grained polygonal structure, and was non-magnetic 

 and tough. On heating for some hours at 500° to 600° C, the material 

 became magnetic and brittle, and developed an acicular, martensite-like 

 structure. The changes occurring were more evident in specimens 

 which were polished and not etched. The alloy quenched from 1000° C. 

 showed no structure. After heating at 400° C. for six hours, and 

 polishing, the surface became covered with interlacing lines, apparently 

 the edges of plates of hard material. Further heating at about 400° C. 

 caused a growth in the amount of the hard constituent, which appeared 

 to form a stiff unyielding network enclosing grains of a more ductile 

 material. A steel containing 2 pic. carbon, 0*14 p.c. manganese, 

 quenched from 1200° C, consisted largely of austenite, which was 

 changed to martensite by heating for 75 hours to 200° C. 



Failures of Heavy Boiler Shell Plates. f — S. A. Houghton dis- 

 cusses the causes of a number of failures of mild-steel boiler plates. 

 Among the defects described and illustrated by photomicrographs are 

 carbonless bands, some of which were high in phosphorus content, local 

 deformation caused by hammering, blowholes, coarse crystallization, 

 and sulphide and silicate inclusions. 



Sulphides in Steel Ingots.} — J. O. Arnold and G. R. Bolsover 

 describe the microscopic forms of the sulphide inclusions found in a 

 number of experimental steel ingots containing different amounts of 

 sulphur and manganese, with about - 25 p.c. carbon. In ingots con- 

 taining less than " 1 p.c. manganese and about • 6 p.c. sulphur, pale 

 brown meshes of iron sulphide only were seen. AVith 0*4 to l'l p.c. 

 manganese, and • 4 to 0*6 p.c. sulphur, the specimens contained both 

 the pale brown iron sulphide and dove-grey manganese sulphide. An 



* Journ. Iron and Steel Inst., lxxxix. (1914, 1) pp. 106-37 (14 figs.). 

 t Journ. Iron and Steel Inst., lxxxix. (1914, 1) pp. 266-316 (31 figs.). | 

 % Journ. Iron and Steel Inst., lxxxix. (1914, 1) pp. 396-406 (7 figs.). 



