PROPERTIES AND USES OF NICKEL STEEL. ./15 
and Company, Le Creusot, France. The effect of the nickel, 
which is added in the proportion of from 2:5 to 3°5 per 
cent., is to produce toughness and prevent cracking. The 
best armour plates to-day are produced by different alloy 
combinations, such as nickel-chromium steel. Again, the 
best. process for face-hardening plates is that due to Fried. 
Krupp, of Essen, which is a great improvement on the 
. Harvey process. 
Gun Steel—The firm of Fried. Krupp employ nickel 
steel, containing approximately 6 per cent. nickel, in the 
manufacture of guns. The American Government has also 
recently built 8-inch breach-loading guns containing 3 per 
cent. nickel. 
Boiler Plate Steel.—it is claimed that Messrs. Carnegie, 
of Pittsburg, U.S. America, was the first to produce nickel 
steel boiler-plates. Messrs. Fried. Krupp have rolled nickel 
steel plates containing various proportions of nickel, but 
they find that alloys containing less than 25 per cent. cannot 
be rolled with a faultless surface; the ordinary 3 and 6 per 
cent. nickel steel plates have rough surfaces. The 25 per 
cent. nickel steel was intended for locomotive fire-boxes, as 
its resistance to corrosion is considerable, but so far as the 
author is aware, no locomotive engineer has designed a 
suitable fire-box for this material. The writer saw a nickel 
steel fire-box at Krupp’s works at Essen which had been 
made for the Hanover railways, but the spacing of the 
stays and thickness of the plates were about the same as in 
an ordinary American steel fire-box. No modification in 
the design was attempted in order to take advantage of the 
special physical qualities of the material, consequently the 
extra stiffness of the plates rendered them much more diffi- 
cult to work than ordinary steel plates, and the results 
were not very satisfactory. The author considers that a 
fire-box of 25 per cent. nickel steel could be designed and 
built which would be much more satisfactory than an 
ordinary steel or copper box; but the stays should be more 
widely spaced, and the thickness of the plates made ,; or 
# of aninch. Fire-box stays have been used experimentally 
in America made of steel containing 3-7 per cent of nickel, 
which have shown considerable endurance in rotative tests— 
much in excess of ordinary carbon steel. 
.Railway Ales, Propeller Shafts, Crank Shafts, Piston 
Rods, Connecting and Coupling Rods, and Forgings for 
Engines, Hydraulic Cylinders, &c.—Nickel stee] has been 
largely used by Messrs. Fried. Krupp in the manufacture of 
large forgings, crank shafts, propeller shafts, crank and 
cross-head pins, railway axles, large piston rods for engines 
