Characteristics of the Static Recrystallization Kinetics of an Intercritically Deformed C-Mn Steel

2004 ◽  
Vol 467-470 ◽  
pp. 293-298 ◽  
Author(s):  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag
Keyword(s):  
Stress Relaxation ◽  
Static Recrystallization ◽  
Avrami Exponent ◽  
Recrystallization Kinetics ◽  
Ferrite Fraction ◽  
Austenite Recrystallization ◽  
Austenite Grains ◽  
Intercritical Region ◽  
Mn Steel ◽  
Kinetics Of

The austenite recrystallization kinetics in the intercritical region of a C-Mn steel is investigated by means of stress relaxation tests. It is found that the Avrami exponent, n, decreases significantly with decreasing temperature, i.e. with increasing ferrite fraction. This behaviour deviates from that of austenite recrystallization in the purely austenitic state, in which case the Avrami exponent is constant and independent of temperature and deformation. To interpret this, the influence of spatial variation of the plastic strain in the intercritical austenite grains on recrystallization kinetics is modelled quantitatively. The modelling results seem to indicate that the strain heterogeneity is responsible for the decreasing Avrami exponent with decreasing intercritical temperature.

Research on Austenite Static Recrystallization Kinetics of Ultra-High Strength Dual Phase Steel

2013 ◽  
Vol 631-632 ◽  
pp. 310-313
Author(s):  
Zhuang Li ◽  
Di Wu ◽  
Wei Lv ◽  
Zhen Zheng ◽  
Shao Pu Kang
Keyword(s):  
Dual Phase Steel ◽  
Static Recrystallization ◽  
High Strength ◽  
Recrystallization Temperature ◽  
Dual Phase ◽  
Recrystallization Kinetics ◽  
Softening Curve ◽  
Austenite Recrystallization ◽  
Deformation Test ◽  
Kinetics Of

In this paper, double deformation test was conducted in a MMS-300 thermomechanical simulator. Austenite static recrystallization kinetics of ultra-high strength dual phase steel was investigated. The results have shown that the softening fractions increase with holding time as a whole. Under deformation temperatures of 950°C, 1000°C and 1050°C, the softening fractions increase with the increase of the deformation temperature. And the softening curve appears relatively flat under deformation temperatures of 950°C. The austenite no-recrystallization temperature (Tnr) of ultra-high strength dual phase steel was between 900°C and 950°C. Double deformation test conditions which promoted Nb(CN) precipitation resulted in a decrease of a austenite recrystallization. Strain induced precipitation of Nb (CN) was the main reason why the softening curve appeared a plateau.

Kinetics of Austenite Recrystallization of Selected Steels Used for Heavy Forgings

2014 ◽  
Vol 782 ◽  
pp. 93-98
Author(s):  
Jakub Horník ◽  
Petr Zuna ◽  
Jaroslav Malek ◽  
František Jandoš
Keyword(s):  
Grain Growth ◽  
Static Recrystallization ◽  
Chemical Elements ◽  
Grain Coarsening ◽  
Recrystallization Kinetics ◽  
Austenite Recrystallization ◽  
One Step ◽  
Kinetics Of

The kinetics of austenite recrystallization was evaluated in range of typical forging temperatures (850 - 1250) °C. The steels SA-508 and 3.5Ni-1.5Cr were compared. The laboratory one step deformation was applied. The effect of selected chemical elements in evaluated steels on grain growth and recrystallization kinetics of austenite and precipitation was monitored using metallographic methods. The retarding of static recrystallization was proved and no abnormal grain coarsening at defined condition was observed.

Modelling the Static Recrystallization Kinetics of Microalloyed TWIP Steels with Different Alloying Contents

2016 ◽  
Vol 879 ◽  
pp. 1465-1470 ◽  
Author(s):  
L. Llanos ◽  
B. Pereda ◽  
B. López ◽  
J.M. Rodriguez-Ibabe
Keyword(s):  
Static Recrystallization ◽  
Quantitative Model ◽  
Recrystallization Kinetics ◽  
Size Evolution ◽  
Wide Range ◽  
Austenite Recrystallization ◽  
Twip Steels ◽  
Fractional Softening ◽  
The Moment ◽  
Kinetics Of

During hot rolling, austenite recrystallization determines the grain size evolution and the extent of strain accumulation, and therefore, it can be used to tailor the microstructure and mechanical properties of the final product. However, at the moment, models describing the recrystallization kinetics of high-Mn steels are scarce and they do not take into account the effect of the alloying elements present in these steels. The aim of this work is to provide a quantitative model for the determination of the static recrystallization kinetics valid for a wide range of high-Mn steel compositions. Softening data determined for steels with different Mn (20 to 30%), Al (0 to 1.5%) and C (0.2 to 1%) levels at different strain, strain-rate and temperature conditions were analyzed. Static recrystallization of the investigated high-Mn steels follow Avrami’s law, with n Avrami exponents which are temperature dependent and lower than those determined for low C steels. A dependence of the t0.5 (time for 50% fractional softening) on the carbon content has been also observed and it was incorporated into an equation for the calculation of this parameter.

Role of deformation twins in static recrystallization kinetics of high-purity alpha titanium

2016 ◽  
Vol 22 (6) ◽  
pp. 1041-1048 ◽  
Author(s):  
Jong Woo Won ◽  
Taekyung Lee ◽  
Seong-Gu Hong ◽  
Yongmoon Lee ◽  
Jeong Hun Lee ◽  
...  
Keyword(s):  
High Purity ◽  
Static Recrystallization ◽  
Recrystallization Kinetics ◽  
Deformation Twins ◽  
Alpha Titanium ◽  
Kinetics Of

Modelling Recovery and Recrystallisation Kinetics after Intercritical Deformation in 0.19 wt% C 1.5 wt% Mn Steel

2004 ◽  
Vol 467-470 ◽  
pp. 329-334 ◽  
Author(s):  
A. Smith ◽  
A. Miroux ◽  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag
Keyword(s):  
Stress Relaxation ◽  
Stress Distribution ◽  
Strain Distribution ◽  
Local Stress ◽  
Stress Strain ◽  
Simple Modification ◽  
Single Grain ◽  
Grain Model ◽  
Mn Steel ◽  
Kinetics Of

The softening kinetics of a 0.19 wt% C 1.5 wt% Mn steel deformed at two intercritical temperatures have been characterised using the stress relaxation technique. Recrystallisation of intercritical austenite has been modelled using a single grain model (Chen et al., 2002 [1]), whilst recovery of both intercritical austenite and ferrite has been modelled using a model in the literature [Verdier et al., 1999 [2]). The models are combined to predict the overall softening kinetics with a rule of mixtures formulation. Comparison of the model with experiment shows significant deviations. The reasons are discussed with reference to the mixture rule and to the local stress-strain distribution which exists in the deformed samples. A simple modification to the model is proposed which takes into account the effect of a local stress distribution in deformed austenite.

Effects of Nb on Strain-Induced Precipitation of NbC and Static Recrystallization for High Nb Pipeline Steels

2010 ◽  
Vol 146-147 ◽  
pp. 1315-1321 ◽  
Author(s):  
Gui Ying Qiao ◽  
Fu Ren Xiao ◽  
Xiao Bing Zhang ◽  
Shao Hui Chen ◽  
Bo Liao
Keyword(s):  
Activation Energy ◽  
Stress Relaxation ◽  
Compression Test ◽  
Static Recrystallization ◽  
Pipeline Steel ◽  
Relaxation Technique ◽  
Start Time ◽  
Pipeline Steels ◽  
Kinetics Of Precipitation ◽  
Kinetics Of

Strain-induced precipitation of complex carbonitrides and recrystallization for three high-Nb pipeline steels with different Nb and C content have been studied by using a stress relaxation technique and two-passes interrupted compression test. Sequentially, the PTT diagrams were obtained, and static recrystallization activation energy was calculated. Furthermore, the effects of Nb and C content on strain-induced NbC precipitation and static recrystallization were discussed. The results confirm the faster kinetics of precipitation and its retarded recrystallization in the case of higher Nb pipeline steel, and that the recrystallization is easier in low Nb pipeline steel in comparison to the case of high Nb steel. However, the effects of Nb on strain-induced precipitation and static recrystallization were associated with the Nb/C ratio. The precipitation start time (Ps) of strain-induced NbC is delayed in lower Nb/C ratio pipeline steel. It is suggested that the reduced supersaturation of Nb can result in the delay of precipitation of strain-induced NbC carbides forming in the low Nb/C ratio steel.

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