January 4, 19 12] 



NATURE 



509 



BASIC OPEN-HEARTH STEEL-MAKING. 



The Basic Open-hearth Steel Process. By Carl Dich- 

 mann. Translated and edited by AUeyne Reynolds. 

 Pp. xii + 334. (London : Constable and Co., Ltd., 

 191 1.) Price los. 6d. net. 



XT EARLY half this work is an elaborate chemical 

 ■^ ^ treatise on gas-producer practice, and the next 

 ninety pages deal with the chemistry of slag-making 

 and the heat equivalents of the oxidisable constituents 

 charged into the furnace. The remaining portion 

 treats of the various basic methods adopted, from the 

 scrap and carbon to the ore and molten pig-iron 

 processes. 



Judging from the tables on German practice the 

 author has been very fortunate in having to deal with 

 pig-irons only slightly inferior in quality to our 

 ordinary hematite varieties, instead of the varied 

 classes of basic pig-iron available in this country ; hence 

 the large outputs obtained. Tables on pp. 190, 191, 

 216, 271, 277, 281, 284, 287, 292, show the character of 

 ihe practice quoted, which is mainly washing metal and 

 running down to the mildest steel; hence the method 

 of sampling the bath mentioned on p. 230, and the 

 lapping of the bath by the judgment of a sample 

 breaker, even if successful under the very favourable 

 conditions assumed, is entirely unsatisfactory where 

 I he sulphur and phosphorus contents are so different, 

 these factors necessitating rapid chemical analysis 

 c(»mbined with the malleability test made by subject- 

 ing a sample to forging. When the metal in the bath 

 iias passed the required malleability test, an addition 

 "i ferro-manganese is made to the bath, and, after 

 illowing it time to settle down again, the heat is 

 ipped. 

 This German and American type of practice with 

 Mnparatively low phosphorus irons is entirely un- 

 itisfactory with English pig-irons, a return of phos- 

 l^horus to the metal being the general result, when 

 the phosphoric acid in the slag exceeds 5 per cent, and 

 the silica is fairly high. Additions of hematite pig- 

 ii<)n, containing over i^ per cent, of silicon or of 

 silico-spiegel, give similar uncertain results. As a 

 consequence the addition of ferro-manganese and other 

 illoys for special steels is made in the ladle, great 

 Me being taken that the last of the additions is added 

 11 before the slag comes. The percentage loss of 

 manganese in the furnace or in the ladle is given at 

 4'), as per H. H. Campbell's acid practice. This is a 

 mistaken idea as regards ladle practice, as advantage 

 1- taken of this even in the acid process to save 

 ro-manganese, whilst in basic work, with slags low 

 i.i iron oxide, the loss of manganese is very small 

 with 005 per cent, of phosphorus in the metal; about 

 percent, when the phosphorus is between 0025 and 

 45 per cent. ; and may reach 35 per cent, when the 

 i i' tal has been taken down to o'oi per cent, phos- 

 1 liorus with o'o7 to o'i2 per cent, of carbon. 



I he paragraph on recarburisation on p. 239 is very 



resting. With skill and experience it is possible 



It regularity to "catch the carbon " that is to work 



process, so that the bath is in a suitable condition 



tapping when the desired carbon percentage is 



NO. 2201, VOL. 88] 



reached, instead of running down to a dead mild or 

 almost carbonless bath and then recarburising. The 

 difficulty spoken of in the molten pig and ore process, 

 the impossibility of regulating the slags so as to stop 

 at the desired carbon content, is due to the ore charged 

 having a curious action of its own, a sudden drop of 

 o'30 to o'40 per cent, of carbon in the sample in a 

 few minutes even if the slag is practically ore-free. 

 This action is very noticeable when a tapping tem- 

 perature is attained. If the slag is not in a fit 

 condition for tapping when the required carbon has 

 been reached, it is not good practice to add large 

 quantities of low-silicon hematite or spiegel to increase 

 the carbon. It is much better and more economical 

 to go down for a lower carbon. 



The removal of sulphur, that bugbear of the basic 

 steel melter, is discussed on pp. 167-171, and dismissed 

 with the conclusion that it is more profitable to take 

 care that sulphurous materials are not charged into 

 the furnace. This is what everyone would do if he 

 could always get nearly sulphur-free materials to use, 

 but much of the English basic material some of us 

 have to use contains 008 and occasionally even up to 

 o"3 per cent, of sulphur; hence one may easily with 

 such material have o"2 per cent, of sulphur in the 

 charge when melted. This can be quickly reduced by 

 the combination of heat and lime whilst the carbon is 

 above 0*3 per cent., the trouble with regard to de- 

 sulphurisation coming when a charge melts out with 

 a low carbon content (p. 194). The sulphur problem 

 is intensified by the fact that materials averaging 

 o"o3 per cent, of sulphur may be charged into a basic 

 furnace and melt out at o"i per cent, sulphur even 

 when melting rapidly, owing to sulphur being taken 

 up from the gas when one had to use a coal contain- 

 ing more than 2*5 per cent, sulphur. It is very good 

 work to finish with 005 per cent, sulphur in the ingot 

 in such circumstances. Although there is not very much 

 clear guidance on practical working, the book as a 

 whole gives a large number of interesting calculations 

 on matters connected with the reactions directly or 

 indirectly bearing on the general working of the basic 

 open-hearth steel process. 



THE GEOLOGY OF NEW ZEALAND. 



The Geology of New Zealand: an Introduction to the 

 Historical, Structural, and Economic Geology. By 

 Prof. J. Park. Pp. xx + 488 + xvi plates, 140 

 figures, 6 maps. (London : \\'hitconiho and Tombs, 

 Ltd., 1910.) Price 10s. 6d. mi. 



THE geology of New Zealand is of exceptional 

 variety and interest. The literature is very 

 scattered, and the valuable reports published by the 

 Geological Survey and Mines Department of New 

 Zealand are often troublesome to those who are not 

 well acquainted with New Zealand topography. Prof. 

 James Park has therefore undertaken a most useful 

 work in compiling a guide to the geology of the 

 dominion ; and ills book will be an indispensable work 

 of reference owing to its clear account of the strati- 

 graphical and economic geology, the det.'iiled biblio- 

 graphy of fifty-eight pages, and the many beautiful 

 plates of New Zealand fossils. The book is well 



