March 20, 19 13] 



NATURE 



7i 



Some of the results upon which these paragraphs 

 were founded are tabulated below. Perhaps the most 

 remarkable results in this series are : — 



111 A plain carbon steel containing about i per cent, 

 of carbon has a yield point of 35 tons per square inch, 

 a maximum stress of 60 tons per square inch, an 

 elongation of 10 per cent, on 2 inches, and a reduction 

 of area of 10 per cent. The addition to such steel of 

 about o-6 per cent, of vanadium raised the yield point 

 from 35 to 65 tons, the maximum stress from 60 to 

 86 tons per square inch, still leaving an elon; 

 7 and a reduction of area of 8 per cent. 



(2) A steel containing o'25 per cent, of carDon a. .a 

 3'3 per cent, of nickel registered a yield point of 

 33 tons, a maximum stress of 42 tons per square 

 inch, an elongation of 26 per cc.it. on 2 inches, and 

 a reduction of area of 53 per cent. 



A practically identical steel, but containing in addition 

 about o'25 per cent of vanadium, recorded a yield point 



I200°C 



series of copyrighted and published reports issued from 

 Sheffield University during the years 1900 to 1902 

 were unconscious plagiarisms of a series of American 

 patents issued during the years 1904 to 1908. This 

 seems to constitute a remarkable problem in 

 psychology. 



A study of what may be called the pure science of 

 vanadium steels made by the lecturer and Prof. A. A. 

 Read, of the University of Wales, has yielded results 

 of profound theoretical and probably practical import- 

 ance. It was shown that vanadium does not 

 seem to form a double carbide with iron. 

 It gradually wrests the carbon from the carbide of 

 iron until when about 5 per cent, of vanadium is 

 present Fe 3 C cannot exist, and only a vanadium car- 

 bide, V 4 C 3 , containing 15 per cent, of carbon is pre- 

 sent, and this constituent is constant, at any rate in 

 tool steels containing up to 14 per cent, of vanadium. 

 The micrographic analysis of these alloys, as shown 

 Fig. 6 (a) and (b). 



1100 



1000 



700 



600 



Carbon 2 7o 



'^GtS 41 



Carbon 0-9% 



Ar 



300 seconds 



Seconds occupied by unit fall in Temperature 



of 50 against 33 tons, a maximum stress of 68 against 

 42 tons per square inch. The elongation was 17 per 

 cent, on 2 inches, and the reduction of area 36 per 

 cent. 



(3) A steel containing 0^25 per cent, of carbon and 

 about 1 per cent, of chromium registered a yield 

 point of 27 tons, and a maximum stress of 41 tons 

 per square inch, together with an elongation of 36 

 per cent, on 2 inches, and a reduction of area of 55 

 per cent. 



The addition of 025 per cent, of vanadium raised 

 the yield point from 27 to 40, and the maximum stress 

 from 41 to 55 tons per square inch. The elongation 

 was lowered from 36 to 26, and the reduction of area 

 from 55 to 53 per cent. 



Thus vanadium differs from tungsten in having an 

 almost magically beneficial effect, not only on cut- 

 ting, but also on structural steels. In connection with 

 vanadium steels it is an interesting fact that the 



no. 2264, VOL - 9 1 ] 



has resulted in the dis- 

 covery of three new con- 

 stituents, viz. vanadium 

 pearlite, vanadium 

 hardenite, and vana- 

 dium cementite. Vana- 

 dium hardenite seems 

 to have a hardness of 

 S (topaz) as compared 

 with the hardness 7 

 (quartz) of iron harden- 

 ite. 



The recalescence re- 

 sults obtained are of 

 great practical, as well 

 as theoretical, interest. 

 They strongly suggest 

 the explanation of the 

 curious thermo-mechan- 

 ical behaviour of high- 

 speed steels, and inci- 

 dentally they appear 

 provisionally to prove 

 that the hardening is 

 not due to allotropic 

 change, but to the 

 carbon change only. 

 Fig. 7 shows (1) the 

 inverse rate recalescence 

 curve of a 0-2 per cent, 

 plain carbon steel, which 

 exhibits all Osmond's 

 critical pointr, viz., Ar 3 , 

 Ar, (with a double 

 peak) an.-' Ar,, the 

 carbon change point; (2) the recalescence of 

 a saturated steel containing o'Sg per cent, of carbon, 

 in which all three points are merged into one very 

 large evolution of heat at 695 C. ; (3) the recalescence 

 curve of a steel containing i'i per cent, of carbon, and 

 io'3 per cent, of vanadium. This curve was regis- 

 tered from 1210 to 505 C. It presents only the 

 double-peaked point Ar„. When the steel is quenched 

 all alone: the above range it still remains quite soft 

 to the file. To harden it it is necessary before 

 quenching in water to heat the alloy above the A, or 

 carbon change point, which takes place at a white 

 heat, near 1400 C. The steel is then very hard. 



Fig. 8 shows the transformation on heating up to a 

 white heat (a) of annealed vanadium cementite into 

 vanadium pearlite, (6) or sorbitic vanadium pearlite 

 into amorphous and topaz-hard vanadium hardenite. 



The advance in concrete cutting; efficiency of turn- 

 ing tools from 1740 to 1912 was then dealt with. It 



Carbon 

 Vanadium 



