236 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1912. 



I merely mention the different nickel alloys for shipbuilding, 

 electric appliances, and for valves. These valuable alloys con- 

 taining 23 per cent and more nickel, are nonmagnetic, and not 

 affected by atmospheric influences; those contaming 30 per cent 

 nickel possess great resistance to electricity, whilst the coefficient 

 of expansion of steel with 45 per cent nickel is only one- twentieth 

 of that of ordinary steel and not greater than that of glass. 



Chromium, tungsten, and molybdenum steel. — It is a very interesting 

 and novel fact that by the thermic treatment alone the microstructure 

 of the cheaper kinds of unalloyed iron plates and iron shapes is so 

 changed that it becomes three times as resistent to the destructive 

 effect of acids. If alloys of iron with chromium, tungsten, molybde- 

 num, and aluminium in certain proportions are thermically treated, 

 this resistance is increased fivefold, as is shown by samples of ordinary 

 carbon steel and chrome nickel steel which underwent a treatment 

 with dilute sulphuric acid for 56 days. 



An alloy of ordinary iron with 5 per cent nickel is an excellent 

 material for withstandmg hot caustic soda. Most astonishing 

 properties are displayed by steel alloys contammg more than 10 

 per cent of chromium and a small addition (2 to 5 per cent) of 

 molybdenum. Such alloys are manufactured in the form of malleable 

 cast and forged iron pieces by Krupp according to the patents of 

 Borchers and JSlonnartz in Aix-la-Chapelle and in the form of rolled 

 tubes by the Mannesmann Rohrenwerken in Remscheid. These 

 alloys are insoluble not only in dilute hydrochloric acid and sulphuric 

 acid, but also in dilute nitric acid, even with the addition of alkali- 

 chlorides, and if they contain about 60 per cent chrome, 35 per cent 

 iron, and 2 to 3 per cent molybdenum they withstand even boiling 

 aqua regia. You will see samples of this extraordinary steel, after 

 treatment with acids, compared with ordinary steel and cast ii'on. 



Tool steel. — It must be especially mentioned that the alloys of 

 iron with chromium, tungsten, and molybdenum tempered by a 

 special process invented by two Americans — Taylor and Wliite — ^find 

 most important uses as quick turning steel for all lands of tools. 



Vanxtdium steel. — The most recent improvements in the manu- 

 facture of steel for tools which must of necessity keep pace in hard- 

 ness with structural steel have been made by the employment of 

 vanadium. Unfortunately, this metal, the use of which is steadily 

 increasing, is still very dear, and the problem which chemists have 

 to solve is to produce it more cheaply. If the price could be reduced 

 perceptibly, metallurgists prophesy a great future for this metal, 

 which exercises a very favorable influence on the microstructure of 

 steel. 



Of great importance are those alloys of iron with chromium, 

 tungsten, and vanadium, which possess a high degree of hardness 



