TREATMENT OP ALLOY STEEL 69 



materials of war, (2) for tools, and (3) for materials of 

 construction. The first are mainly alloys of nickel, chro- 

 mium, and tungsten or combinations of these elements. 

 The makers of these alloys also conduct the heat treatments 

 and guard their methods jealously. Alloy tool steels in- 

 clude air hardening and high speed steels together with a 

 large number of steels of the "special" class containing 

 relatively small amounts of alloying elements, giving them 

 special characteristics and fitness for particular and severe 

 requirements. One product of this class is remarkable in 

 that it undergoes no change in form upon hardening ; more- 

 over, it hardens in oil sufficiently to make a remarkably 

 good tap, cutter, or die. 



The alloys receiving most attention to-day are those of 

 the third class namely, materials of construction, and 

 particularly the automobile steels. These are in general 

 of three kinds nickel steels, chrome nickel steels, and 

 chrome vanadium steels. Many different analyses are made 

 under each class. The difficulty of producing sound nickel 

 steel, free from pipes and seams, has injured the reputa- 

 tion of this most useful alloy with many users. This dif- 

 ficulty has been greater than need be because certain steel 

 companies have mistaken a quality proposition for a ton- 

 nage proposition, and have offered nickel steel at absurdly 

 low prices, wholly inconsistent with uniformity of analysis, 

 careful workmanship and inspection. Discriminating 

 users recognize this fact and are willing to pay a premium 

 for the product of certain mills, because their steels are 

 made in smaller tonnages and units, are more carefully 

 handled from start to finish, are worked under hammers 

 rather than in blooming mills, are made from purer ma- 

 terials and carefully inspected when done. The best is 

 none too good for constructing the vital parts of an automo- 

 bile, and when a concern has secured the best that the 

 market affords, it has but taken the first step in producing 

 good parts. Next come the forging and machining and 

 the heat treatment, for better or worse. It is money wasted 



