METALLURGY. (!RON AND STEEL.) 



383 



electrical engineering was referred to, and the 

 lecture ended with an appeal for the more ex- 

 tended study of the physical properties of metals. 



The report of the committee of the Iron and 

 Steel Institute which was appointed to ascertain 

 whether it would not be possible to make the 

 terminology of metallography less complicated 

 and more precise comprises a glossary of the 

 more important terms used by authors of memoirs 

 dealing with the subject, with the exact equiv- 

 alents in French and German. Care was taken 

 in performing the work to exclude controversial 

 matters, and when a definition was not universal- 

 ly accepted to quote the definition given by the 

 specific author. 



The investigations of Prof. J. O. Arnold and 

 Mr. Andrew Me William on the composition of 

 steels were confined to pure iron and carbon steels 

 such as are produced in the best crucible practise. 

 The authors reached the conclusions that the 

 clear and definite constituents of hardened steel 

 are (a) hardenite, Fe 24 C., of which the whole 

 mass consists only in the case of 0.89 per cent, 

 carbon steel; (ft) ferrite, Fe, which segregates 

 more or less in unsaturated carbon steels in spite 

 of the rapid action of quenching; and (c) 

 cementite, which segregates more or less in sat- 

 urated steels in spite of the rapid action of quench- 

 ing. The indefinite portions of the hardened steels 

 consist in unsaturated carbon steels of hardenite 

 containing more or less unsegregated ferrite, or 

 in supersaturated carbon steels of hardenite con- 

 taining more or less unsegregated cementite. 

 Martensite is not a constituent, but a crystalline 

 structure developed at high temperatures. It is 

 marked in saturated carbon steels by preferential 

 etching lines; in unsaturated carbon steels by 

 striae of ferrite; and in supersaturated carbon 

 steels by striae of cementite. The existence of the 

 constituents sorbite, troosite, and Austentite is 

 extremely doubtful. Students should guard 

 against apparent or false constituents really due 

 to optical causes or to obscure polishing -or etch- 

 ing effects. The views expressed by the author 

 were opposed on the reading of their paper at the 

 meeting of the Iron and Steel Institute by Sir 

 W. C. Roberts- Austen, Mr. J. E. Stead, and others. 



Iron and Steel. The first paper read at the 

 summer meeting of the Iron and Steel Institute, 

 at Diisseldorf, Germany, was by Mr. W. Briig- 

 mann, of Dortmund, and showed that almost .all 

 of the increase in the world's production of pig- 

 iron from 18,300,000 tons in 1880 to 39,000,000 in 

 1901 had been shared by Germany and the United 

 States, the weight of pig-iron made in America 

 in 1901 having been more than three and a half 

 times what it was in 1880, and that of Germany 

 more than three times greater. The large increase 

 in the German production was ascribed by the 

 author to the development of coal-mining, which 

 had made available a good supply of native fuel, 

 and to the opening up of the iron deposits of 

 Luxemburg and Lorraine, by which a supply of 

 native ores suitable for the basic process of steel- 

 making had been placed at the disposal of the 

 manufacturer. The dephosphorization of iron in 

 the converter exercised the most important in- 

 fluence in the rise of the German iron industry. 

 While the make of basic pig-iron had developed 

 to be more than 4,800,000 tons, or 2,000,000 tons 

 more than the total iron production of 1880, and 

 the make of foundry pig-iron had also increased 

 from 200,000 tons in 1880 to 1,500,000 tons in 1900, 

 the manufacture of pudclling-iron and spiegel had 

 declined from about 2,000,000 tons to 1,800,000 

 tons. The reduction in wrought-iron is regarded 

 as no more than the inevitable consequence of the 



advance in steel. Notwithstanding the develop- 

 ment of the German iron industry, the blast- 

 furnaces of the land have not been able to meet 

 the demand. The author spoke of the excellent 

 equipment of the German iron-works, and said 

 that their appliances had to a large extent been 

 based on those of American works, but were not 

 mere copies of them. Among special features of 

 German iron-making practise spoken of were the 

 recovery of by-products from gases evolved in 

 coke-making, improvements in mechanical ap- 

 pliances, the extensive adoption of the practise of 

 carrying iron in the liquid state from the blast- 

 furnace to the steel-works, the increasing utiliza- 

 tion of blast-furnace gas, and the application of 

 surplus power to the manufacture of cement from 

 blast-furnace slag. 



Mr. Axel Wahlberg, reviewing Brinell's re- 

 searches into the influence of chemical composi- 

 tion on the soundness of steel ingots, maintained 

 that the percentage of carbon and the casting 

 temperature, which had hitherto been considered 

 the agents responsible for the presence and posi- 

 tion of blow-holes, were to be regarded as exerci- 

 sing a secondary influence. The principal cause 

 of the defect was the presence of manganese and 

 sometimes of aluminum contained in the ingot 

 metal at the moment of casting. 



In a paper on the Properties of Carbon in the- 

 Hearth of the Blast-Furnace, read before the Iron 

 and Steel Institute, Mr. W. J. Foster showed that 

 by increasing the temperature and diameter of the 

 hearth more carbon would be exposed to the oxids, 

 with proportionally less interruption by the gases 

 that are decomposed in the neighborhood of the 

 tuyeres; hence more carbon would be converted 

 into carbon monoxid in the hearth per unit of air 

 introduced at the tuyeres, and consequently an 

 increased rate of driving would result. 



In a paper on the overheating of low-carbon 

 mild steel, Prof. Heyn, of Berlin, submitted as 

 his principal conclusions that when low-carbon 

 mild steel is annealed at temperatures above 

 1,000 C. there is an increase in the degree of 

 brittleness, if the annealing process is sufficiently 

 long. This increase is more considerable and man- 

 ifests itself the sooner the higher the temperature 

 of annealing. Prolonged annealing, say uninter- 

 rupted for fourteen days at temperatures between 

 700 and 890 C., produces no increase in brittle- 

 ness. In such cases, where the brittleness of the 

 material in its initial state was not yet at the 

 lowest degree possible, that degree is attained 

 by this treatment. Between 1,100 and 900 

 C. there exists a temperature limit, above which, 

 if annealing is carried on for a longer period and 

 at an increasing temperature, the degree of brit- 

 tleness increases. Below this limit, however, such 

 is not the case. Overheating does not occur at 

 most extreme white heat, but manifests itself at 

 considerably lower temperatures, which must, 

 however, exceed the temperature limit just re- 

 ferred to. By suitable annealing, the brittleness 

 of overheated low-carbon mild steel can be elimi- 

 nated. If annealing is carried on above 600 C., a 

 short period of about half an hour is sufficient. 

 Longer annealing must be the more carefully 

 avoided the more the temperature limit between 

 1,100 and 900 C. is exceeded, otherwise the signs 

 of overheating will reappear. Below 800 C. an 

 annealing of even five hours is not enough to elim- 

 inate the brittleness in the overheated metal ; but 

 by annealing of one day's duration at tempera- 

 tures between 700 and 850 C. this object can be 

 attained. If low-carbon mild steel which has been 

 annealed for a longer period at a high enough 

 temperature, so that after undisturbed cooling it 



