Magnetic Permeability of various Alloys of Iron. 
117 
The effect on magnetic hardness produced by different percentages of various 
metals added to iron is shown in fig. 12, where the ordinates represent coercive 
force and the abscissze percentages of the added element. 
case of the tungsten steels is noticeable. 
The steady rise in the 
The wonderful softness produced by the 
addition of silicon to steel is not shown in fig. 12, but will be referred to presently. 
Coerovve force. 
LS 
ae a eee 
aye, 11D 
el = 
Ee 
10 77 
Per-centage & added element 
The addition of chromium to aluminium steel has the effect of hardening it, 
and, therefore, injuring the valuable magnetic properties of a pure aluminium 
steel. Aluminium and chromium have, therefore, opposite effects on steel 
magnetically. 
TasLeE XII.—Chromium Aluminium Steels (Plate VIII.). 
Marks. Percentage. 
Cr Al 
Tron — — 
MUGS ID) | Dek 2:25 
» Bl ie6 4°50 
Max. induction. 
17480 
14460 
13705 
15070 
14400 
Retentivity. 
7120 
8990 
6860 
9690 
9500 
$2 
Coercive force. 
1°66 
3°52 
1:77 
6:00 
8:00 
nwrisG, Hie Se 
1560 11090 
1180 18090 
1042 13830 
964 26550 
363 35780 
