Hot Torsion Tests - A Reliable Rolling Simulation Method for C-Mn Steels

2016 ◽  
Vol 879 ◽  
pp. 1783-1787 ◽  
Author(s):  
Fulvio Siciliano ◽  
Brian Allen ◽  
David Ferguson
Keyword(s):  
Flow Stress ◽  
Hot Deformation ◽  
Simulation Method ◽  
Absolute Temperature ◽  
Mean Flow ◽  
Torsion Testing ◽  
Torsion Mode ◽  
Mean Flow Stress ◽  
The Mean ◽  
Hot Torsion

Torsion tests have been proven to be a successful method to simulate the hot rolling of steels. Simulation work performed at a laboratory scale together with the analysis of the resulting mean-flow-stress behavior, leads to important metallurgical information to be considered during full-scale rolling processes. In this work, two different hot deformation schedules of C-Mn steels have been performed on a Gleeble simulation system in hot torsion mode. In addition to the torsion tests, the mean-flow-stresses of industrial rolling data were analyzed. Industrial hot deformation schedules simulated using hot torsion and the mean-flow-stress values were plotted versus the inverse of absolute temperature in the same graph. All points match the same behavior showing that torsion testing is a reliable hot working simulation method.

Determination of the Non-Recrystallisation Temperature (Tnr) of Austenite in High Strength C-Mn Steels

2012 ◽  
Vol 706-709 ◽  
pp. 2722-2727 ◽  
Author(s):  
Jai Gautam ◽  
Alexis G. Miroux ◽  
J. Moerman ◽  
Carla Barbatti ◽  
Peter van Liempt ◽  
...  
Keyword(s):  
Flow Stress ◽  
Work Hardening ◽  
High Strength ◽  
Mean Flow ◽  
Alternative Approach ◽  
Interpass Time ◽  
Work Hardening Rate ◽  
Mean Flow Stress ◽  
Hot Torsion

In the present study non-recrystallisation (Tnr) and Ar3 temperatures have been determined for the C-Mn steels from multi-pass hot torsion experiments with continuous cooling in the temperature range of 1260°C to 600°C. Results show that Tnr decreases with increasing strain/pass, strain rate or interpass time. An alternative approach based on the work-hardening rate is proposed for the determination of Tnr and is shown to be more suitable in case the usual mean flow stress method does not provide a clear Tnr value.

Constitutive Analysis of the Mean Flow Stress of a Nb- and N-Bearing Austenitic Stainless Steel Biomaterial

2020 ◽  
Author(s):  
Nelson Luis Costa dos Santos Filho ◽  
Eden Santos Silva ◽  
Clodualdo Aranas ◽  
Fulvio Siciliano ◽  
Gedeon Silva Reis ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Austenitic Stainless Steel ◽  
Mean Flow ◽  
Constitutive Analysis ◽  
Mean Flow Stress ◽  
The Mean

Modeling of the Resistance to Hot Deformation and the Effects of Microalloying in High-Al Steels under Industrial Conditions

2005 ◽  
Vol 500-501 ◽  
pp. 195-202 ◽  
Author(s):  
Fulvio Siciliano ◽  
Evgueni I. Poliak
Keyword(s):  
Flow Stress ◽  
Hot Deformation ◽  
High Strength ◽  
Microalloyed Steels ◽  
Hot Strip Mill ◽  
Mean Flow ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Hot Strip ◽  
Mean Flow Stress

The hot strip rolling of advanced microalloyed high strength steels still represents a new task to many mills due to the lack of data on the hot deformation resistance. With the aid of processing data from the Ispat-Inland hot strip mill, the “measured mean flow stresses” are calculated from the mill force using the Sims analysis and taking into account roll flattening, slip ratio and the redundant strain. A modification of the Misaka mean flow stress equation is proposed for C – Mn – Si – Al steels microalloyed with up to 0.02 % Nb. The effects of alloying and microalloying are then estimated. A new fitting parameter shows excellent agreement with the mean flow stress data from industrial processing of advanced high strength microalloyed steels. However, during the second half of the rolling schedule (lower temperature region), indications of austeniteto- ferrite transformation were found.

Modeling of the Microstructural Evolution and Mean Flow Stress during Thin Slab Casting/Direct Rolling of Niobium Microalloyed Steels

2005 ◽  
Vol 500-501 ◽  
pp. 221-228 ◽  
Author(s):  
Fulvio Siciliano ◽  
L.L. Leduc
Keyword(s):  
Flow Stress ◽  
Microalloyed Steels ◽  
Hot Strip Mill ◽  
Thin Slab ◽  
Mean Flow ◽  
Thin Slab Casting ◽  
Slab Casting ◽  
Mean Flow Stress ◽  
Direct Rolling ◽  
The Mean

Mill logs obtained from the Hylsa CSPTM (thin slab casting/direct rolling – TSC/DR) mill were examined so that the mean flow stresses at each pass were calculated using the Sims equation modified to take into account the forward slip ratio, the redundant strain and the work roll flattening. The mean flow stresses were then compared to predicted values obtained from a model. The microstructures during the CSP process were predicted by a mathematical model which was initially derived for conventional slab/roughing mill/hot strip mill (HSM) processing route. The adapted model takes into account the deformation of the as-cast structure in the finishing CSP mill, by using particular microstructural equations to calculate the softening kinetics and grain sizes. The main metallurgical features such as the occurrence of Nb(C,N) precipitation, the softening mechanism which takes place (static or metadynamic recrystallization) as well as the strain accumulation between passes were calculated. The mean-flow-stress results obtained from the calculations are in good agreement with the mill data. The present analysis indicates that it is possible to produce fine-grained microalloyed steels with homogeneous microstructure in thin slab casting/direct rolling processing.

Effect of Dynamic Transformation on the Mean Flow Stress

2012 ◽  
Vol 84 (3) ◽  
pp. 253-258 ◽  
Author(s):  
John J. Jonas ◽  
Chiradeep Ghosh ◽  
Vladimir V. Basabe
Keyword(s):  
Flow Stress ◽  
Mean Flow ◽  
Dynamic Transformation ◽  
Mean Flow Stress ◽  
The Mean
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