Prakt. Met. Sonderband 46 (2014) 257
ring structural ferrite peaks will be superimposed [5], making difficult a direct observation. Moreover, the
1e y-grains as strong initial texture in SAF 2101 and 2205 and the heavy orientations acquired at high
ctly related to deformations in all DSS hinder Rietveld refinements, making this method no reliable for a
ore anodic [8] phases estimation. In any case, the presence of the y-peaks at the highest thickness
same phase. reduction underlined that, if SIM formed. it did not replace the whole austenitic phase.
Ictions can be
stenite is less
odifications in 3.4. MAGNETIC MEASUREMENTS
After demagnetization, the AR and %CR DSS were subjected to magnetic tests. SAF 2304
and 2205, characterized by a well-balanced microstructure and by a discrete magnetic
level of ferrite, were examined by means of the AC device. On the contrary, AC was not
able to saturate SAF 2101 and 2507, owing to the high ferrite content in the former and to
anite gave rise the high magnetic level of ferrite in the latter; therefore, the DC magnetometer was used.
> FCC phase, The results provided by AC and DC measurements are not directly comparable but, if SIM
ides, a greater transformation took place, an increasing in saturation magnetic field (Bmax) is expected.
be addressed 0457 a 2101 00,
he ferrite was 0,40-| --©--2304 (ac)
yresence of a - ae
g of the ferritic 030.
agmented. g 025-
® 0,20 -
20s i
0,05 ]
oo] in - .
0.05 +- —_— _——————
a 20 40 60 80 100
thickness reduction (%}
Fig. 4 — Saturation magnetic field (Bmax) as a function of the deformation degree.
A progressive rising of Bmax Was registered in SAF 2101 and 2304 by increasing the
deformation degree (Fig. 4), as already observed by [6,7]. In SAF 2205, only a little
variation toward higher Bmax values at the highest thickness reduction was noted, whereas
the saturation field remained almost unchanged in SAF 2507. The measurements revealed
that cold rolling caused a strong increasing in magnetic phase amount in Lean DSS, which
can be ascribed to SIM formation [6,7]. Moreover, SIM seemed also to form at the highest
thickness reduction in SAF 2205, but in significantly lower extents respect to Lean DSS,
owing to its greater stability. Conversely, SAF 2507 was found to be highly stable, and the
saturation magnetic field only exhibited some fluctuations arising from local microstructural
0 solubilisation inhomogeneities.
304 and 2507
ther hand, the
to the principal
and the heights 4. SUMMARY
ld deformation
Jhest thickness In the present work, the effects of cold rolling on various Duplex Stainless Steels (DSS)
were investigated. The steels — SAF 2101, 2304, 2205 and 2507 — were deformed at
ss steels, since various thickness reductions (from 15% to 85%) and the developed microstructural
ırred, SIM and features were investigated.
2507
