692 MANGANESE DEPOSITS OF INDIA: ECONOMICS. [pART III : 
13% of manganese and 1% carbon. Although, on account of its hardness, 
very difficult to work, manganese-steel is now being used extensively for 
many purposes where combined hardness, toughness, and consequent 
great ability to resist grinding wear, are required. Among such appli- 
cations niav be mentioned all kinds of mining machinery, especially that 
used for crushing and milling, such as the jaws of rock-breakers, crusher- 
heads, rolls, etc., and also mine-car wheels, dredging machinery, and safes. 
Manganese-steel rails are used in America on the Boston Elevated Rail- 
way ^ wherever there are sharp curves, with consequent great wear of the 
rails. The manganese-steel rails are found to be more economical than 
either carbon-steel or nickel-steel rails, owing to their excessively slow 
rate of wear. Manganese-steel has also been used for tools, such as 
axes and razors. 
The above gives only a brief outline of the uses of manganese in the 
metallurgy of iron and steel. The effects of man- 
iion'^^and TteeL'^""''"''''^ ganese on iron and steel have been summarized 
by H. M. Howe - as follows :— 
'It is easily removed fiom iron by oxidation, being oxidized even by silica, and 
partly in this way partly in others it restrains the oxidation of the iron, while some- 
times restraining sometimes permitting the oxidation of the other elements com- 
bined with it. It is also apparently removed from iron by volatilization. Its 
presence increases the power of carbon to combine with iron at very high tempera- 
tures (say 1400"C ), and restrains its separation as graphite at lower ones 
By preventing ebullition during sohdification and the formation of blow- 
holes, by reducing or removing oxide and silicate of iron, by bodily removing sulphur 
from cast-iron and probably from steel, by counteracting the effects of the sulphur 
which remains as well as of iron-oxide, phosphorus, copper, silica and sihcates, and 
perhaps in other ways, it prevents hot-shortness, both red and yellow. (It does not 
however counteract the cold- shortness caused by phosphorus.) These effects are 
so valuable that it is to-day well nigh indispensalale, though admirable steel ^\as 
made before its use was introduced by Josiah Marshall Heath 3. 
It is thought to increase tensile strength slightly, hardness proper, and fluidity, 
to raise the elastic hmit, and, at least when present in considerable quantity, to di- 
minish fusibihty. It is generally tiiought to diminish ductihty : evidence' will be 
ofl'ered tending to show that its ctfeots in this respect liave been exaggerated. While 
1-5 to 2-5% of manganese is nearly universally admitted to cause brittleness, steel 
with 8% of manganese is astonishingly ductile : with further increase of manganese 
the ductility again diminishes. Steel with 8 to 10% manganese, thougli extremely 
tough, is so liard as to be employed without quenching for cutting-tools. It is denied 
and asserted with equal positiveness that manganese confers the power of becoming 
harder when suddenly cooled, but it is generafly thought to make steel crack when 
quenched.' 
1 Iron 'ind Sled Maq., IX, |)p. 170-481, ..May 1905. Abstracted from Railroad 
Gazette, .March 17, 1!»05. 
2 ' The Melalluigy of Slcel I, [>. 42, (1891). 
3 Percy : Iron and fcitocl, p. 840. 
