Steels_ Metallurgy and Applications, Third Edition

46 Steels: Metallurgy and Applications

1.8

1.6

._= |

>

1.0

,~~ ~ll 0.007 wt%C

'oj2 0'.4' o16 o18
Manganese content (wt%)
I
Figure 1.46 Effect of manganese content on the rm values of cold-rolled and annealed
steels with various carbon contents, heating rate lO0C/h, held at 700C for 1 hour (Osawa
et al. 8~

1.2"

1.8- * ~o---'-'~

::=1.4 "

~, .. ,

"E 1.8 - .-, ~.....e. ~

.

2.0 ,q 0.027 ~*~,A,

1.6" t~

0.032 ~%AI

0.043 ~%AI

1.4-

1.8- .,l~~ 0.068 wt'%AI

. "l,,, ..,.,,.4~ .....41,.4r ~
1.4- i l l l Ill l =
10 50 100 300
Heating rate (~

Figure 1.47 Variation of rm value with heating rate for batch-annealed, aluminium-killed
steels containing different aluminium contents (Shimizu et al. al)

energy, Q, equal to 250 KJ/mole which corresponds approximately with that for
the self-diffusion of iron. 83

Continuously annealed, aluminium-kiUed steel

The developments in continuously annealed, aluminium-killed mild steels have
been concerned primarily with matching the properties previously available from
batch-annealed steels. It has been necessary, therefore, to compensate for the lack