Magnetic Permeability of various Alloys of Iron. 
Tasie XIV.—Chromium, Nickel-Chromium, and other Steels. 
Marks. Percentage. 
Cr Ni W Mn © 
eA I 8°25 = “= = 0:43 
| UN: 9°50 = a= = 1:09 
1286 A 0°75 2°75 = 0:25 
» © 1:75 2°50 a = 0°31 
1210 D 4-50 2°50 = = 0-41 
1189 B 0°75 _ 2-00 == 0°25 
687 a= = 3:25 2°25 0:40 
1254 C = 4-00 2 3°75 0°57 
TaBLe X1V.—(continued). 
Marks. Max: induction, | Retentivity. | for H=8. | Coercive force. 
Tron 17480 7120 1560 1°66 
1177 I 12280 8480 150 12:25 
WM 12600 10560 460 8°25 
1286 A 16990 7980 1250 3:00 
aks 15610 11450 500 7-9 
1210 D 14060 10100 = 13:1 
1189 B 16470 12510 1160 5:8 
687 15820 12430 840 65 
1254 0 6610 3890 125 19°6 
L19 
It will be observed that a 3+ per cent. chromium steel has a high coercive 
force and low permeability, but when the chromium is increased to 94 per cent. 
the coercive force is diminished and the permeability increased, whilst the max. 
induction remains practically the same. 
Whether this anomalous behaviour be 
due to the higher carbon in the latter specimen, or some accidental difference in 
annealing, we cannot say. Adding nickel to a low chromium steel improves it 
magnetically, the max. induction is increased, and the permeability very largely 
so, as in specimen 1286 A, which has under 1 per cent. of chromium. 
As the 
quantity of chromium increases in the next two specimens, the nickel remaining 
