Barrett — On the Physical Properties of Manganese Steel. 361 



truth, and after a considerable expenditure of time and capital, dis- 

 covered that by adding the ordinary ferro-manganese of commerce to iron 

 or steel in sucb proportions as to produce in the steel or decarbonized iron 

 under treatment a percentage of manganese varying from 7 to 20 per 

 cent., that the most beneficial results could be obtained. Such per- 

 centage is regulated according to the purpose for "which the steel is 

 required. For instance, to produce a steel suitable for armour-plates 

 and other purposes, as we mentioned last week, they add about 10 per 

 cent, of rich ferro-manganese, containing, say , 80 per cent, of manga- 

 nese, thus obtaining a steel containing about 10 per cent, of manganese. 

 For railway purposes they add about 1 1 per cent. ; for steel toys and 

 tools, about 12 per cent. They pour this ferro-manganese into the 

 molten steel under treatment, thoroughly incorporating it therewith, and 

 then run it into ingot or other suitable moulds, and allow it to cool, after 

 which it is ready for use, as it requires neither tempering, rolling, 

 forging, nor hardening. This treatment of steel in suitable proportions, 

 according to requirements, appears to be novel, and renders the steel so 

 manufactured harder, stronger, denser, and tougher than most steel now 

 manufactured, even when forged and rolled. This steel may, however, 

 be forged and rolled in the ordinary manner. For casting it has the 

 advantage that it possesses greater freedom from honeycombs and similar 

 defects ; but the most peculiar property is its great toughness, combined 

 with extreme hardness. It is through this that the hitherto indispen- 

 sable processes of rolling, forging, hammering, hardening, and tempering 

 may be dispensed with, thus effecting for many articles an enormous 

 •economy in time, labour, and expense. In casting its fluidity enables 

 fine steel castings to be made without misrunning, and approaching in 

 smoothness iron castings. 



" Amongst the samples of the steel placed on the table at the meeting 

 of the Mechanical Engineers was a sample test bar containing 12 per 

 cent, manganese, bent double when cold, though hard enough for turning 

 iron ; a sample from same ingot shows a tensile strength of 42 tons per 

 square inch, with 20'85 per cent, elongation; several hammered pieces; 

 a manganese adze, containing 20 per cent, manganese, just as it left the 

 mould; an axe, containing 12 per cent, manganese, just as cast in the 

 rough, had chopped through iin. square iron. This, like the others, had 

 not been hardened or tempered, only the edge ground." 



In a Paper read before the American Institute of Mining 

 ^Engineers in May, 1884, some tests of this steel were given, show- 

 ing the extraordinary tenacity and hardness of the material. 

 When hammered or drawn into rods it loses some of its toughness, 



