610 Professor J. 0. Arnold [Jan. 24, 



My late colleague, Dr. A. McWilliam, and I were commissioned 

 to investigate at Sheffield University the accuracy or otherwise of the 

 curve specified in the patent. The results are embodied in the curves 

 on the screen (Fig. 7), The co-ordinates are, horizontally hardening 

 temperatures in degrees Fahrenheit, and vertically cutting efficiency 

 numbers obtained by the approximate and relative formula e = t x s-, 

 where " e " is an efficiency number, " t " the time endurance in minutes, 

 and " s " the cutting speed cseteris paribus in feet per minute. It 

 will be seen that with a steel containing about 18 per cent of tungs- 

 ten, 3 per cent of chromium and 1 • 3 per cent of carbon, the maxi- 

 mum efficiency number of about 6000 is obtained at the lowest tem- 

 perature 830° C, or 1526° F., after which the higher the hardening 

 temperature the less the efficiency number, which at 1300° C. or about 

 2400° F. has fallen to 500, or only twice the efficiency of plain carbon 

 steel. In a similar steel containing, however, only • 7 per cent of 

 carbon, the efficiency number at 830° C. or 1526° F. is only about 500, 

 but the efficiency steadily rises with the hardening temperature till 

 at 1300° C. or 2372° F. it reaches the astounding number of about 

 32,000. In a word, there is no breaking-down range, and so far from 

 the percentage of carbon being immaterial, the cutting efficiency is 

 actually a function of the carbon and hardening temperatures. 



It has already been pointed out that the year 1870 marked the 

 commencement of the tungsten era, and 1880 that of the tungsten- 

 chrome era. But the years 18D9 to 1902 inaugurated what is destined 

 to be the most remarkable epoch of the three, namely, the vanadium 

 era. During these years a series of researches on the influence of the 

 comparatively rare metal vanadium on plain carbon steel and on alloy 

 steels were carried out in the experimental steel works of Sheffield 

 University. At that time (1899) vanadium was 60s. per lb. In 

 1912, owing to the large demand, the cost had fallen to 10s. per lb. 



The first report, having reference mainly to cutting steels, was 

 issued in June 1900, and the second and third reports respectively in 

 January and June 1902. The results were briefly summarized in the 

 two paragraphs shown on the screen. 



June 28th, 1900. 



" The results of this preliminary investigation have 

 profoundly impressed upon nay mind the future before 

 vanadium as a steel-making element, and even at this 

 early stage of my knowledge of its effect, I venture to say 

 that its action resembles that of tungsten, but that it is 

 from ten to twenty times as powerful as the latter 

 element." 



Jamiary Hth, 1902. 



" It is already evident that as a steel -making element 

 vanadium will place in the hands of metallurgists and 

 engineers a very powerful weapon, because it is now 



