October 21, 1922] 



NATURE 



all receive detailed and careful treatment. The author 

 has brought to bear upon his task the experience of a 

 practical and enthusiastic angler, and the zest of a keen 

 student. While he realises the more serious aspects of 

 his theme, he has dealt kindly by the general reader 

 and writes in a light-hearted, attractive, and un- 

 pedantic manner. In this way he should be instru- 

 mental in developing a wider interest in and stimulating 

 further research into the history of one of the oldest 

 industries, and has given us the story of progress from 

 a humble and despised craft to a popular and respected 

 art. Henry Balfour. 



The Metallurgy of Iron and Steel. 



(1) Engineering Steels. By Dr. L. Aitchison. (Re- 

 constructive Technical Series.) Pp. xxxi + 34S + 4S 

 plates. (London: Macdonald and Evans, 1921.) 

 25s. net. 



(2) The Case-Hardening of Steel : An Illustrated Ex- 

 position of the Changes in Structure and Properties 

 induced in Steels by Cementation and Allied Processes. 

 By H. Brearley. Second edition. Pp. xi + 207. 

 (London : Longmans, Green and Co., 1921.) 165. 

 net. 



(3) Iron-Founding. By B. Whiteley. (Pitman's 

 Common Commodities and Industries.) Pp. 131. 

 (London: Sirl. Pitmanand Sons, Ltd. ,1921.) 35.net. 



(1) ' I MIE advance of metallurgy in recent years has 

 ± placed at the disposal of the engineer a wide 

 range of new materials, including alloy steels which 

 so far surpass the older, plain carbon steels in strength 

 and toughness as to constitute a new class of metals. 

 In the face of such diversity the engineer finds difficulty 

 in selecting the most suitable material for a given 

 purpose, and is not in a position to judge between the 

 products offered by manufacturers, or recommended by 

 specialists. There are in existence many excellent 

 memoirs and a few books on the subject, but they are 

 written for the metallurgist, and assume a technical 

 knowledge that lies outside the usual field of study of 

 the engineer. It is highly desirable that the user of a 

 metal should understand its properties as well as the 

 maker, and Dr. Aitchison has made the attempt, 

 largely successful, to describe the steels now available 

 for engineering purposes, without assuming a knowledge 

 of chemistry or metallurgy. 



The title of Dr. Aitchison's book must be interpreted 

 in a rather restricted sense. The engineer is interested 

 in such steels as those used for ship and boiler plates, 

 rails, and girders, but he will find little in reference to 

 them, the work being mainly concerned with steels 

 required by the automobile and aircraft industries. 

 It is these steels of high tensile strength, often required 

 NO. 2764, VOL. I 10] 



to withstand severe alternating stresses, that present 

 the greatest difficulties of specification and testing, 

 and it is very necessary that the information regarding 

 them should be collected and placed clearly before 

 the engineering user, as has been done here. There is 

 a very brief account of methods of manufacture, suffic- 

 ing to indicate the distinction between various classes 

 of steel, and a discussion of ingot structure, so far as is 

 required to explain the possible sources of defects in 

 forgings. 



It is probably on account of the limitation mentioned 

 above that only piping steel is described, and the 

 subject of blowholes is not mentioned. Steel castings 

 are omitted entirely, although of great interest to the 

 engineer who uses high tensile steel forgings for other 

 parts of his machine. The desire to avoid chemical 

 and metallurgical difficulties leads to a somewhat 

 excessive simplification of the chapter on heat treat- 

 ment, and the author's account of hardening and his 

 explanation of the critical points is rather misleading, 

 although not likely to cause misunderstanding of the 

 practical instructions. It should be said that the style 

 is easy and readable throughout. 



The subject of mechanical testing is well treated, 

 proper attention being given to the determination of 

 the fatigue range and its relation to the other measure- 

 ments usually made in the testing laboratory. Much 

 of the experimental material in this chapter is taken 

 from the author's reports to the Aeronautical Research 

 Committee. His conclusions may not always be 

 accepted, but the importance of the subject is rightly 

 emphasised, and the descriptions of fatigue tests and 

 the short accounts of other special methods of testing 

 are valuable. There are very few references to original 

 sources, but a full bibliography of papers relating to 

 the determination of hardness is given. 



The alloy steels are considered in detail, the pro- 

 perties of each steel, as modified by different heat 

 treatments, being shown by means of diagrams similar 

 to those published by the Automobile Steel Research 

 Committee ; these diagrams provide a useful guide to 

 the characteristics of the various classes of steels. 

 Case-hardening and cold-working are other subjects 

 dealt with. 



The book is very well printed and illustrated, many 

 of the best plates being selected from Mr. Brearley's 

 works, while others show special types of testing 

 machines. The whole subject of the relative value of 

 tests for steels of this class is in a state of flux, and an 

 authoritative statement is not yet to be expected, but 

 Dr. Aitchison has made a good beginning, and his 

 efforts will be welcomed by engineers. 



(2) The first edition of Mr. Brearley's book on case- 

 hardening was published in 1914, and it is an indication 



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