The Montgomery advertiser., 1903-09-20
WHAT STEEL REALLY IS.
Bessemer Steel is not Steel at all, il
 is Wrought Iron.

Bessemer Steel Is not Steel at all, 1t Is Wrought Iron.
 Prof. H. M. Howe in Engineering Maga- zine.
 What are the iron and steel of com
 merce and industry? Examined under the
 microscope they prove to be composite of granite substances, intimate mechanical mixtures on conglomerates Of microscopic particles uf certain quite distinct, we'll defined. simple substances. in widely vary ing proportions. The chief of the sub stances are:
 First-Pure Cor nearly pure) metallic | iron called ferrite, soft, weak, very duc- tile, with high electric conductivity, and
 in general like copper in Its qualities. col or excepted. -f' S-+'t '%t | Second-A definite iron carbide. Fe3C, called cementite. which is harder than
 glass and nearly as brittle but probably
 very strong under gradually and axially
 applied stress.
 [ Take immediately as the most import
 ant fact the most essential part of the
 skeleton about which the various phe-
 nomena are to be grouped that the great
 the engineer and probably to the world
 at large are essentially intimate mixtures or conglomerates of these two strikingiy
 different microscopic constituents-ferrite extremely hard and brittle, the former,
 like copper, the latter like glass. The properties of several of the classes may indeed be influenced and very profoundly. by thermal and mechanical treatment, and by the presence in certain of them of slag or of graphite; but the fact on which
 our attention should be concentrated at
 first is this: that the difference in proper ties between the different industrial
 classes of iron and steel are due chiefly to difference in the ratio which the ferrite bearo to the cementite.
 Until about 1860 there were only three
 important classes of iron-wrought iron,
 steel and cast iron. Tine essential charc-
 acteristic of wrought iron was its nearly
 complete freedom from carbon; that of
 steel it's moderate carbon content (say be-
 tween 0.3O and per cenD. which, though great enough to confer the property or
 being rendered very hard by sudden cool | ing. yet was not so great as to make the metal brittle when cooled slowly: while | tha2 of cast iron was carbon content so | high as to make the metal brittle whether cooled quickly or slowly. This classilca- | ton was based on carbon content, or on iron. and certain classes Of steel which
 then were important. necessarily con tained much slag or ''cinder,' because they were made by welding together pas
 ty particles of metal in a bath of slag.
 without subsequent fusion. But the best class of steel crucible steel, was freed
 from slag by fusion in erucihles; hence It's
 Between 1s6O and 1870 the Bessemer and open-hea processes introduced new class of iron. today called "miid'' or low CdTDOn SIeel. WHICH ldCheu lHe eSSclltIdl property of steel, the hardening power. yet differed from the existing forms of wrough iron in its freedom from slag, and cast iron in being very malleable. Log. cally it was wrought iron. the sence of which was, that it was CD iron as distinguished from steel and @ nal
 eable. that Is. capable of being
 wrought" This name did not nlea=o those interested In the new product. be- cause existing wrought iron was a low priced material. The only just.fisble al formative would have been to assign d wholly new product: but as steel was as- sociated in the public mind with superb ortty. 1t appeared more attractive to ap- propriate it's valuable name. This was done with the excuse that the new pro duct resemhled one class of steel--cast steel-tn being free from slag: and. after a period of protest, all acquiesced in cal ing the new product steel" which is now it's firmly established name. The cd va rieties of wrought iron. steel, cast steel and cast iron preserve their old names the new S,lass is called steel by main force. As result, certain varieties sucn as blister steel. are called "steel'' solely because they have the hardening power and others. such as iow-carbon steel. solely because they are free from slag.