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Large number of numerical modeling works are carried out for rolling and cooling parameters optimization for these steels whose microstructure simply consist of F+P or F+B structure[3~4], and few works have been carried out for DP steel .
Ferrite grain size can be formulated as Eq.3 according to Liu[5]
Effects of Si on ferrite grain size and ferrite and martensite fraction are shown in Fig.2b).
Mn can also refine ferrite grain size.
Finer ferrite grain size with higher Mn content is obtained as shown in Fig.2c.

For in-situ annealing experiments the pre-deformed single crystals were heated under high vacuum to temperatures of 280-470±15 ºC in a number of steps.
The position of grains is defined by boundary nodes (bnodes) that delimit closed polygons.
For case study 1 recovery within an individual grain is modelled in detail.
Grain boundary curvature and stored strain energies are used as driving forces for grain boundary migration.
White circles and boxes depict example areas for stress translation i.e. continuation of subgrain boundaries across a grain boundary and subparallel subgrains crossing whole grains, respectively.

The results show that, in the (Fe1-x Crx)2B phase, the number of covalent electron pairs and the weaker bond energy are increased by the substituting atom-Cr.
The hypothesis is as following:① the experimental covalent bond distances of (Fe1-xCrx)2B are equal to those of Fe2B; ② Fe cB Fe nlRlR ),(),( and B cn in (Fe1-xCrx)2B are also equal to those of Fe2B; ③ the cell structure and the identity bond number of (Fe1-xCrx)2B are equal to those of Fe2B too.
Furthermore, cracks and long axis of Fe2B grain are vertical.
In addition, [002] is the direction of Fe2B grain growth along, which is the reason that cracks in Fig.1(a) are vertical with long axis of Fe2B grain.

Equal-channel angular pressing (ECAP) is an efficient method of improving strength of metallic alloys through (sub) grain refinement to, typically, the sub-micrometer level by introducing intensive plastic strain into materials through repetitive pressing.
Introduction Equal-channel angular pressing (ECAP) is an efficient method of improving strength of metallic alloys through (sub) grain refinement to, typically, the sub-micrometer level by introducing intensive plastic strain into materials through repetitive pressing [1-4].
S. than the current alloy ECAPed in a sold solution state (~320 MPa vs. ~570 MPa), though the former was multiply ECAPed to higher pass numbers of 4 and the applied ECAP processing temperature was lower (293K vs. 433K).
In most cases, however, this procedure sacrificed some strength due to (sub) grain coarsening and dislocation-density reduction.
Number next to symbols denotes the pressing number[10].

But this theory absolutely does not take into account the fact, that finally these grains by some way acquire the same crystallographic orientation.
Studied pellets of uranium dioxide were obtained by the procedure, including (a) cold pressing and (b) sintering by a number of regimes.
This signifies, that in the studied sample the number of grains, having such orientation near the pellet axis, is by 1.2 times more, than in the textureless sample.
The fact is that in the conglomerate of mutually misoriented grains their inevitable real structure anisotropy hinders from the stress relaxation.
Because of the structure anisotropy thermal expansion coefficients of neighboring grains prove to be mutually disagreed, promoting rise of new microstress.

The measured parameter was the number of cycles to failure.
Too much heat transfer could raise the size of the prior austenite grains, which can not assure good mechanical properties [6].
With adequate etching, the prior austenite grains are easily seen at an optical microscopy image (Fig. 5.).
The TEP versus the number of cycles can be seen in Fig. 7.
Thermoelectric power depending on the number of cycles Conclusions As the consequence of the examinations, one of the main conclusions is that the most fatigue sensitive zones of the weld are the fusion line and beside that, the coarse-grained zone.

Different numbers of layers were deposited for both processes, to study the effect of thickness to the characteristics of the ZnO thin films.
The variation of the thin films thickness, which was depending on the number of layers deposited, slightly diminished the transmittance when the number of layers increased.
The higher the transmittance of P2 compared to P1 may be due to the lower optical scattering caused by the densification of grains followed by the grain growth and also the fewer grain boundary [13, 14].
It can be seen that the resistivity of the films from P1 is lower than P2 regardless of the number of layers.
Using both processes, different film thickness were obtained by varying the number of layers deposited.

Table 2 Cooling rates chosen in ANN models Cooling curve number 1 2 3 4 5 6 7 8 9 Cooling rates[oC/s] 120 1.5 1 0.5 0.2 0.1 0.056 0.025 0.0167 The predicted CCT diagrams were illustrated in Fig.2.
Table 3 Chemical composition of experimental steels Steel number Chemical composition[mass%] C Mn Si Ni Mo W E1 0.17 1.50 0.26 0.62 0.47 0.26 E2 0.16 1.50 0.20 0.73 0.48 0.92 Table 4 Tensile properties of the experimental steels at T/2 of model forging Steel number Tensile strength [MPa] Yield Strength [MPa] Elongation [%] Reduction in area [%] E1 664 543 26 73 E2 730 590 23 67 It can be seen that with the tungsten content increases, tensile strength and yield strength increase, elongation and reduction in area decrease.
Fig.5 Quenching microstructures of E1 and SA508-3 steel at T/2 of the forging (a) E1 (b) SA508-3 It is shown in Fig.5 that the microstructures of both steels consist of grain bainite and ferrite.
According to grain bainite transformation[9] carbon diffused adequately and was rich in longer distance when Bs was higher, so the Martensite/Austenite(M/A) island has larger size, less quantity and bigger spacing, vice versa.
Fig.6 Temper microstructures of E1 steel at T/2 (a) 650oC (b) 670oC (c) 700oC Because quenching microstructure of E1 steel contains grain bainite, the change of grain bainite during temper process is important.

The corresponding drop in the intensity of the most prominent Si peak is attributed to the decrease in Si content in the sample and also to the increased distortion of the Si lattice with increase in iron as more number of Fe atoms breaks into the Si lattice during high energy milling.
It can be seen that grain size of Si decreases and corresponding lattice strain increases with increase in milling time.
The estimated average grain size of Si, in all the samples after 25 hours of milling is found to be 40nm and the corresponding lattice strain is ~4.4 x 10-3.
These results further confirm the phenomena of grain size reduction and nanocomposite formation with increasing milling duration.
The average grain size of Si has been found to be 40nm after 25h of milling and the corresponding lattice strain is 4.4 x 10-3.

The chemical composition of steels Chemical element 10G2FB 17GS VSt 3kp 15KH2МFA 06G2NAB 15KH2NMFA C 0.10 0.15 0.17 0.12 0.08 0.11 Mn 1.60 1.31 0.59 1.20 1.50 1.65 Si 0.33 0.51 0.22 0.26 0.25 0.50 S 0.004 0.016 0.025 0.01 0.01 0.015 P 0.020 0.017 0.016 0.01 0.02 0.025 Cr — — — 0.04 — 0.04 Al — — — 0.13 0.03 — Ti 0.021 — — — — — As — 0.004 0.002 — — — V 0.097 — — — — 0.08 Nb 0.025 — — — 0.15 0.06 Mo — — — 0.30 — 0.30 Ni — — — 1.30 0.70 1.30 Mathematical Model and Discussion The value of the yield point is determined by the total contribution of a number of hardening mechanisms.
sт=, (1) where n is the number of hardening mechanisms acting in the alloy.
(2) here s0 is the resistance of the metal lattice to the movement of free dislocations (the Peierls-Nabarro barriers), Dss.h is the solid solution hardening by doping elements and impurities dissolved in it (solid-solution hardening), Dsd.h. is the hardening due to the resistance of sliding dislocation to other dislocations in the crystal (dislocation hardening), Dsd. is the hardening caused by the formation of dispersed particles of the second phase during the decay of a supersaturated solid solution (dispersion hardening), Dsg.h. is the grain and subgrain boundary hardening (grain boundary hardening), Dsp is the hardening of pearlitic phase.
=kyd-0,5, (7) where ky for ferrite-pearlite steels is 16 - 21 N/mm3/2; d is the average grain size.
From (11) it is seen that all components of the hardening, in addition to the grain refinement leads to increase dT50.