Prakt. Met. Sonderband 50 (2016) 221 
micrographs in with the use of image analysis. This correlates well with the value of 41.6 known from 
vin refinement thermodynamic equilibrium by applying the lever rule in the pseudobinary phase diagram Fe-Fe;C. 
20 um 20 um | 
Ai b) 
Fig. 3: Initial microstructure in the bright drawn state consists of ferrite grains, fine pearlite, carbides and some 
martensite (a). and microstructure after reheating and slow cooling is comprised of grains of ferrite and coarse pearlite 
300 1000 (b) 
05 
se we chose the 0.4 
gure 3a, it is 
microstructure 
olonies which 03 
ed during the 2 
esent within the = ee 
ution in ferrite “oa 
1°C (Cm), and Ca 
1site is small 
v. Reheating of 01 
in separate Ac 
rmation is also 
austenite at a 0 
the ferrite 100 200 300 400 500 600 700 800 wo 
n the current Tcl 
and 789° 
C Fig. 4: Electrical resistance changes during thermal cycling of Ck45 
on occurs at The changes in electrical resistance can be interpreted by considering that austenite remains the 
r interval : ; : . Ce 2 . 
continuous phase, at the time the ferrite grains are precipitated. Additionally, the austenite becomes 
; and Ar; on the . . : . . A 
in-bet the enriched in carbon during the formation of ferrite, which increases its resistivity. In contrast the 
TDELWSCH subsequent formation of pearlite between the points Ps and Pr is registered as a substantial decrease 
nset and . . . . ; | 
rts th as all the austenite decomposed into ferrite and cementite which removed carbon from solid 
956 CXEITS IC solution. During further cooling to room temperature no other reactions are appreciable. The 
n interpreting ; . . : . 
wer resistivit measured temperatures are in very good correlation with the theoretical values obtained from the 
A is about 42%, Fe-Fe2C phase diagram and analytical methods [14], where the highest differences amount to about 
| 0a 
Cr 
Haating 
Cooling