Effect of thermomechanical parameters on the critical strain for ultrafine ferrite formation through hot torsion testing

2004 ◽  
Vol 367 (1-2) ◽  
pp. 152-161 ◽  
Author(s):  
H Beladi ◽  
G.L Kelly ◽  
A Shokouhi ◽  
P.D Hodgson
Keyword(s):  
Critical Strain ◽  
Torsion Testing ◽  
Ferrite Formation ◽  
Hot Torsion

scholarly journals Hot Ductility of TiNb IF Steel Slab after Hot Torsion Testing

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 752 ◽  
Author(s):  
Konrádyová ◽  
Longauerová ◽  
Jonšta ◽  
Jonšta ◽  
Longauer ◽  
...  
Keyword(s):  
Temperature Cycling ◽  
Hot Ductility ◽  
If Steel ◽  
Cast Slab ◽  
Torsion Testing ◽  
Steel Slab ◽  
Temperature Dependences ◽  
Hot Torsion ◽  
Average Size ◽  
20 Nm

The aim of the work was to evaluate the hot ductility loss in TiNb stabilized IF steel directly from the continuously-cast slab using hot torsion testing (plastometry) in the temperature range 600–1250 °C according to the basic programme, and also after temperature cycling. A good match of the temperature dependences of number of turns to failure (Nf) and intensity of deformation Se was confirmed. In both cases, the existence of three temperature areas with decrease in plasticity to a minimum was confirmed. The two-stage temperature cycling according to the CT1150 and CT900 programmes mostly resulted in a decrease in plasticity compared to the basic programme. The most significant effect of cycling was related to the CT900 programme below the maximum plasticity in the base programme at 850 °C. A less pronounced decrease was observed for CT1150 cycling below the maximum plasticity in the base program at 1050 °C. In the case of CT1150 cycling, more complex particles were observed at the fractures compared with the basic programme, namely carbonitrides of Ti and Nb in combination with oxisulfides respectively, then Ti nitrides with oxisulfides or oxides and, in addition, complex (Fe,Nb)P4, (Ti,Nb)3S4 type particles. Their mean size determined statistically using TEM was much finer, only 20 nm versus 42 nm in the basic programme. Similarly, CT900 cycling revealed finer particles with an average size of 37 nm compared to 105 nm in the basic programme. The observed particles were Al oxides, Ti(N,C) and (Ti,Nb)2S, in contrast to the particles probably of TiFe and FeMnS in the basic programme. The decrease in plasticity corresponded to the finer particles, newly created in the temperature cycling.

Effect of Thermo-Mechanical Variables on the Dynamic Ferrite Transformation Induced by Hot Deformation in 0.22C-Mn Steel

2006 ◽  
Vol 510-511 ◽  
pp. 510-513 ◽  
Author(s):  
Jae-Young An ◽  
Young Jae Kwon ◽  
S.I. Kim ◽  
Duk Lak Lee ◽  
Chong Mu Lee ◽  
...  
Keyword(s):  
Strain Rate ◽  
Critical Strain ◽  
High Strain ◽  
Stored Energy ◽  
Micro Structure ◽  
Dynamic Transformation ◽  
Austenite Grain ◽  
Nucleation Sites ◽  
Hot Torsion ◽  
Mn Steel

Hot torsion of a C (0.22 wt%)-Mn steel was used to investigate the influence of thermomechanical arameters on the strain induced dynamic transformation (SIDT) of ferrite. The pecimens were strained as a function of strain rate (0.05/sec - 5/sec) and strain (- 5.0) at right bove Ar3 temperature. The critical strain to initiate dynamically transformed ferrite nuclei during deformation increased as increasing the strain rate. On the other hand the completion of SIDT was hifted to larger strain by decreasing strain rate. This is due to the fact that the dynamic ransformation of ferrite was processed in the interior of austenite grain as well as at grain boundary y large stored energy and many nucleation sites for high strain rate. The dynamic transformed micro-structure of ferrite was developed to higher angle and the grain size could be refined to ~3 ㎛ at strain of 3.0 and 5/sec.

Deformation Induced Pearlite Transformation and Spheroidization: Effect of Alloying Additions

2011 ◽  
Vol 409 ◽  
pp. 666-671 ◽  
Author(s):  
Matteo Caruso ◽  
Hector Verboomen ◽  
Stéphane Godet
Keyword(s):  
Microstructure Evolution ◽  
Hot Deformation ◽  
Eutectoid Steel ◽  
Torsion Testing ◽  
Alloying Additions ◽  
Steel Grades ◽  
Cr Addition ◽  
Hot Torsion ◽  
Kinetics Of ◽  
Undercooled Austenite

The aim of this research is to investigate the effect of Cr and Al (strong ferrite formers) on the strain-induced γ-to-pearlite transformation in eutectoid steels. The microstructure evolution during the hot deformation of three eutectoid steel grades was investigated using hot torsion testing. More specifically, the steels were deformed to strain levels varying from ε = 0,5 to ε = 1,5 at their specific Ar1 temperature. Hot deformation of the undercooled austenite leads to strain-induced γ-to-pearlite transformation and to the almost instantaneous spheroidization of the formed carbides. The corresponding microstructures consist of submicronic cementite particles and ferritic grains that are 1-5 μm in size. It is shown that 1,5% Cr addition and 0,5% Al addition increase the equilibrium transformation temperature but slower significantly the kinetics of the strain-induced transformation and consequently reduce the kinetics of cementite spheroidization and of ferrite recrystallization.

A study of the hot-working behavior of SiC−Al alloy composites and their matrix alloys by hot torsion testing

1987 ◽  
Vol 18 (2) ◽  
pp. 303-312 ◽  
Author(s):  
J. R. Pickens ◽  
T. J. Langan ◽  
R. O. England ◽  
M. Liebson
Keyword(s):  
Hot Working ◽  
Al Alloy ◽  
Torsion Testing ◽  
Hot Torsion

scholarly journals ON THE TRIAL MANUFACTURING OF HOT TORSION TESTING MACHINE

1956 ◽  
Vol 42 (10) ◽  
pp. 980-985 ◽  
Author(s):  
Kikuo Tajima ◽  
Keijiro Kugai
Keyword(s):  
Testing Machine ◽  
Torsion Testing ◽  
Hot Torsion
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