1904] Liquid Air Temperatures on Iron and its Alloys. 331 



and ordinary steels. It is therefore all the more curious that the 

 iron-nickel-manganese alloy (HUB) described later, entirely differs in 

 this respect, where the effect of low temperature is not only nil, but 

 there is a positive increase in ductility. The ball tests on specimen 

 No. 26 shows an increase in hardness at - 182 C. of 70 per cent., viz., 

 from 205 to 372. Three other specimens, Nos. 26 E, F, and G are 

 also interesting as showing the effect of| quenching upon Mn steel, 

 from temperatures of 605, 800, and 950 C. in liquid air, the 

 tests being then carried out at normal temperatures. The specimens 

 E and F give similar results to those that would be obtained by 

 quenching in ordinary cold water at 600 and 800 C., i.e., little or no 

 increase in ductility. On the other hand, in specimen 26 G, quenched 

 from 950 C., there is no doubt the result obtained, 66 tons tenacity 

 with 38 per cent, elongation, is excellent, but it is not any better than 

 can be obtained by quenching in water at 15 C. It is important to 

 here mention that the three specimens E, F, G, were all non-magnetic 

 at - 182 C., showing that there is no change in the magnetic properties 

 of manganese steel at low temperatures. This experiment finally 

 settles quite a number of misunderstandings in metallurgical literature 

 which have arisen on this subject, namely, that at no range of increase 

 or decrease in temperature (provided this is not, as regards high 

 temperature, sustained for any length of time) does any marked 

 change in magnetic property occur in manganese steel. 



The effect of low temperature on Iron alloyed with Two other Main 

 Elements. Taking first the alloys of Iron, Nickel, and Chromium. 

 Tests Nos. 78 (C 0'25, Cr 0'64, Ni 2-67 per cent.) and 81 

 (C 0-89, Cr 2-00, Ni 1'92 per cent.). In the first instance in the 

 presence of low carbon the nickel shows its toughening influence, 

 as at - 182 C. the tenacity rises from 38 to 61 tons, the elongation 

 only falling from 20 17 per cent. In the latter specimen the 

 effects of the nickel are not so apparent owing to the higher 

 carbon, but the elongation does not entirely disappear. Another 

 specimen of this latter material after quenching in oil at 760 C., and 

 then water at 650 C. showed an increase in tenacity at - 182 C. of 

 from 81 105 tons, the elongation being, however, reduced from 

 7J per cent, to nil. The embrittling influence of the carbon is seen in 

 both instances. In the next specimen, No. 79 (C 0'31, Cr 1'80, 

 Ni 2-60 per cent.), the ductility is not affected, remaining at 15 per cent. 

 Notwithstanding the considerable presence of chromium, the nickel 

 asserts itself in this specimen, the tenacity rising from 49 79 tons. 

 A similar result was also noticeable in specimen No. 107 (C 0'17, 

 Cr 1-55, Ni 3*02 per cent.), the tenacity rising to 59 tons, and the 

 ductility dropping only from 25 20^per cent. Test No. 80 (C 0*64, 

 Cr 2-01, Ni 12-24 per cent.). In this specimen the very high tenacity at 

 the normal temperature (115 tons) does not appear to be affected by the 

 VOL. LXXIV. 2 c 



