Magnetic Permeability of various Alloys of Iron. 



Group 15. — Manganese-Silicon Steels. 



Other low manganese-silicon steels are given in Groups 1 and 3, Series B, from 

 whicli 611 is transferred for comparison, and 1379 D is also transferred from 

 Group 2, Series B. By comparing 601 with 687 in Group 14, or with 53 in Group 

 2, p. 76, it will be seen how powerfully silicon affects the conductivity of steel. 



In the next group we see the effect of adding copper to manganese steel. 

 Group ] 6. — Manganese-Copper Stekls. 



From Group 2 it will be seen that a steel (53), having 2| per cent, of 

 manganese, but no copper, has rather a lower conductivity than 1240 in 

 the above table ; the carbon it is true is rather lower in the latter specimen. 



We will now examine the effect of adding a second metal to the chromium 

 steels. Here is a group of chromium-aluminium steels. 



Group 17. — Chkomium-Aluminium Steels. 



P 2 



