August 12, 1920" 



NATURE 



743 



The Research Department, Woolwich. * 



By Sir Robert Robertson, K.B.E., F.R.S. 



Metallurgical Branch. 



'X*HE metallurg-ical branch of the Research De- 

 -l- partment had been established for some 

 years before the war, the staff consisting^ of 

 four metallurg-ists. As work increased, addi- 

 tions became imperative, and before the armis- 

 tice the scientific staff numbered thirty-seven, of 

 whom a number were women. At the end of 1916 

 the branch removed into a new building- 120 ft, 

 long and 55 ft. wide, divided into laboratories well 

 equipped for mechanical testing of all kinds, 

 chemical analysis, microscopy and photomicro- 

 graphy, experimental heat-treatment, the thermal 

 study of alloys, and other 

 branches of physical metallurgy. 

 I'igs. 4 and 5 show two of these 

 laboratories. The machine shops 

 of the Department, on which 

 metallurgical work made great 

 demands, were much extended 

 and improved. 



During the war the metal- 

 lurgical branch was mainly occu- 

 pied with a great variety of prob- 

 lems connected with the metallic 

 materials of warlike stores used 

 by the Navy, Army, and Air 

 I'^orce. The work was carried 

 .)ut in close association with the 

 Ordnance Committee and other 

 Departments concerned. It is 

 possible to mention here only a 

 very few of the specific problems 

 attacked. 



Before the war the manufa( 

 ture of gun forging-s was in the 

 hands of a few armament firms 

 of long- experience, but with 

 the gfreat increase in output 

 which took place from 191 5 onwards a wider 

 source of supply was drawn upon. The heat-treat- 

 ment applied was not always the most suitable, 

 and sometimes caused serious irregfularity of pro- 

 perties throug^hout the forgings. Much was done 

 to define the temperature limits appropriate to the 

 different steels employed and to secure their 

 application, thus eliminatine- those weaker tubes 

 which were so frequently found among- those 

 which failed by stretching, choke, or expansion. 

 The inspection tests were improved, especially in 

 the determination of the vield point, a matter of 

 great importance in a highly stressed structure 

 such as a gun. 



The extreme brittleness of some g^n forgingfs 

 put forward for test directed attention to the 

 occurrence of " temper-brittleness '' in nickel- 

 chromium steel, and made investigation an urgent 



1 Continued from p. 712. 



NO. 2650, VOL. 105] 



necessity. Slow cooling in the furnace after 

 tempering was identified as the main cause of 

 this form of brittleness, which is detected by the 

 notched-bar impact test, and was accordingly for- 

 bidden by specification. Examination of samples 

 representative of forgings in current supply made 

 at the beginning of 1916 and at the end of 1918 

 showed that the notched-bar impact figure of the 

 average nickel-chromium steel forgoing had very 

 greatly improved, with no detriment to the other 

 mechanical properties. The study of the notched- 

 bar test was continued in association with the 

 British Engineering- Standards Committee, and 

 much knowledge was gained as to its significance 

 and conditions of application. 



KlG. 4. — Portion of mechanical testing laboratory 



Much time has been given to the study of the 

 elastic properties of steels and of the effect of 

 overstrain and recovery, a subject of importance 

 in connection with the strength of guns and their 

 construction by methods involving tHe use of in- 

 ternal pressure. 



Erosion, wear, and the development and exten- 

 sion of cracks in the bore have been studied in 

 rifle and machine-gun barrels, as well as in guns. 

 Many questions were solved in connection with 

 the design and rnanufacture of bullet envelopes 

 and the cores of armour-piercing bullets. 



A method of applying the Brinell hardness test 

 for the individual testing of H.E. shells which 

 for one reason or another were in question as to 

 their strength was developed, and resulted in the 

 successful utilisation of very large numbers of 

 shells which might otherwise liave been rejected. 



The numerous components of ammunition and 



