476 



NATURE 



[September 29, 19- 



and economic production is of very recent growth. 

 It has very truly l)een said that every great metal- 

 lurgical discovery has led to a rapid advance in other 

 directions. I will as before deal with the railway as an 

 exampli'. 



We can scarcely appreciate now the conditions 

 which existed from a metallurgical point of view on 

 our railways when the British Association first met at 

 Liverpool in 1837. Iron — made laboriously, hetero- 

 geneous in character and expensive of production not 

 only in money but also, owing to the heavy character 

 of the methods employed, detrimental to the very char- 

 acter of the workman — was the only material available 

 for the various parts of the mechanism of the loco- 

 motive and for the rails. However improved the 

 methods of manufacture were, there could never have 

 been a universal development of rail traction if it had 

 depended upon material made in such a way. 



The demand was met at the Cheltenham meeting 

 of the British Association in 1856 when Bessemer made 

 public the invention he had already been working on 

 for two years, which was to ensure a cheap method of 

 production of a material so essential to transport. One 

 should also mention with Bessemer the name of 

 Mushet, whose work helped so materially in getting 

 rid of the red shortness which in the early days gave 

 such trouble. We are apt at the present day to 

 belittle somewhat the work of Bessemer in view of the 

 more improved methods now employed, but his name 

 must for ever stand out as the one who made cheap 

 transport possible. After tlie use of manganese in one 

 form or the other as a deoxidiser and a " physic " for 

 sulphur, there remained, however, the baneful effect, 

 due to phosphorus, which prevented the use of the 

 ores of more general occurrence. There have been 

 few more epoch-making announcements made at 

 meetings of technical subjects — although this was not 

 appreciated at the time by many of the audience — 

 than S. G. Thomas's announcement of the discovery 

 of the " basic " process, which he made at the meeting 

 of the Iron and Steel Institute in March 1878. His 

 work, associated with that of his cousin, Gilchrist, was 

 the result of close scientific research. 



Another investigation which has given great results 

 in transport has been the ever-growing use of alloy 

 steels. For the scientific inception of these we owe a 

 great debt to Sir Robert Hadfield. His first investiga- 

 tions materially affect transport to-day. Mushet had 

 previously worked on self-hardening tool steel con- 

 taining tungsten, but the work was only carried out 

 on a small scale. In 1882 Hadfield had produced 

 manganese steel. This is a most remarkable product 

 with its great toughness, and is extensively used for 

 railway and tramway crossings, where resistance to 

 abrasion is of great value. This was the first of a 

 remarkable series of alloys which have made possible 

 the motor car and the aeroplane as we have them 

 to-day. 



Continuing his investigations, in 1889 Hadfield 

 produced the compound of iron and silicon known 

 as low hysteresis steel. Indirectly, this is of the 

 greatest interest from a transport point of view, for 

 when used in transformers it not only reduces the 

 hysteresis losses, but also allows of a considerable 

 saving in the weight of core material. 



NO. 2813. VOL. 112] 



From these early uses of alloy steels there has 

 up a large numi)er of alloys, many of which are ol i 

 very greatest use for various transport purpow**. 

 is not too much to say that the mod< 

 the result of the material now at the d« 

 l)oth for the engine and for the stru( t 

 strength of some of the chrome-nickel 

 with their ductility is extraordinary, and is due ii 

 only to the composition of the metal, but also '<• ' 

 results which have been obtained by |>atient s< 1 

 investigations relating to their heat-treatment. I 

 one other example, one may quote the use «• 

 chrome steel— for the early investigations into 

 we owe so much to Brearley, and to its later d- 

 ments to Hatfield also — for the valves of a< 

 engines, subjected as they are to high tcr 

 At one time it looked as if the advantii: 

 high compression and its resultant hi;, 

 might be lost owing to the inability of ordinar\ 

 to resist this heat, but the employment of 13 pc 

 chrome steel allowed work in this direction 

 continued. 



It is not only with steels that we have been benefit 

 so much from research. The case is as marked wr 

 light alloys, which have aluminium as a Iwise. 1 

 latter itself is the result of investigation along s< i 

 lines, and in aeronautical work particularly mu 

 been done towards giving a metal both light and 

 by the work of VValter Rosenhain, F. C. Lt, 

 others. 



It may be said that all I have dealt with up to t 

 present has been the result of special investigation, 

 and that " ordered knowledge " is not of assistance to 

 an everyday engineer. The results I have obtained 

 with the assistance of my colleagues, especially L. 

 Archbutt and H. A. Treadgold, dealing with the solid 

 locomotive crank axle are of interest in this connexion. 

 Not only is the axle subjected to stresses set up by 

 rev^olving it while it is loaded with the weight of a 

 portion of the locomotive on its axle-bearings and by 

 the steam pressure on the pistons transmitted to the 

 crank-pins, but it has also to withstand the shocks set 

 up by its running on the rails, which cannot be calcu- 

 lated. For about twenty years we have endeavoured 

 to get the knowledge we have obtained into an ordered 

 state, from observation and discussion with the metal- 

 lurgists attached to the various manufacturing firms. 

 Certain points are obvious, such as the necessity of a 

 good micro-structure, and we can with confidence say 

 that the steel " shall be as free as possible from non- 

 metallic enclosures, and that the micro-structure should 

 show uniformly distributed pearlite in a sorbitic 

 very finely granular or lamellar condition and be fr< 

 from any nodular or balled-up cementite. It must 

 also be free from any signs of segregation and from 

 any coarse or overheated structure." (Extract from 

 Midland Railway specification for crank-axle forging^ '» 

 Toughness rather than strength is required, and t 

 studied consideration of these points has led to a.. 

 increased life in miles of the crank axles of the 3000 

 locomotives owned by the Midland Railway Con - 

 in spite of the fact that they have been con- 

 growing in size, in pressure on the pistons, and m itic 

 work expected from them. 



It will be appreciated that the above result, which 



