Formation of Ferrite-Cementite Ultrafine Grained Microstructure by Warm Compression for SM490 Martensite Steel

2007 ◽  
Vol 558-559 ◽  
pp. 539-544
Author(s):  
J.H. Li ◽  
Ping Guang Xu ◽  
Yo Tomota ◽  
Yoshitaka Adachi
Keyword(s):  
Dynamic Recrystallization ◽  
Low Carbon Steel ◽  
Block Size ◽  
Low Carbon ◽  
Fine Grained ◽  
Orientation Imaging ◽  
Ultrafine Grained ◽  
Different Temperatures ◽  
Dynamic Recrystallization Behavior ◽  
Ultrafine Grained Microstructure

The low carbon steel, SM490 was austenized at different temperatures followed by quenching into water to obtain martensite microstructures with different grain sizes. Then specimens were heated up to 600°C followed by warm-compression at έ=1.7x10-3 s-1 (strain rate) to investigate the dynamic recrystallization behavior. The influence of pre-tempering before compression was also investigated. The microstructure observations were performed with FE-SEM and orientation imaging analysis with EBSD. It is confirmed that the dynamic recrystallization occurred in the tempered martensite as well as the as-quenched marteniste, resulting in fine grained ferrite microstructure with about 2μm. The dynamic recrystallization grain size is hardly dependent on the block size of initial martensite.

scholarly journals Influence of Annealing on Strength of Ultrafine Grained Low Carbon Steels by ECAP

2010 ◽  
Vol 638-642 ◽  
pp. 1899-1904 ◽  
Author(s):  
T. Akita ◽  
Masahide Gotoh ◽  
Sergey V. Dobatkin ◽  
Kazuo Kitagawa ◽  
Yukio Hirose
Keyword(s):  
Low Carbon Steel ◽  
Hardness Test ◽  
Carbon Steels ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Reactions ◽  
Fine Grained ◽  
Angular Pressing ◽  
Ultrafine Grained

In the present study, ultra fine-grained low carbon steel samples were processed by equal channel angular pressing (ECAP). Mechanical properties of the specimens annealed statically at several temperatures were evaluated by tensile and hardness test. In addition, grain sizes of the specimens were measured by SEM-electron back scattering pattern (SEM-EBSP) and X-ray diffraction analysis. Differential scanning calorimetry (DSC) measurement also evaluated thermal reactions in anneal process of the specimen. As a result, the grain size was changed at the temperature between 550oC and 600oC drastically and the tensile strength also became lower at the same temperature. The relation between yield stress and averaged grain diameter of specimens obeyed the Hall-Petch relation except the normalized specimen. Behavior of grain growth and recovery in structural observation by EBSP corresponded to reaction signal of the DSC curve.

Grain refinement and formation of ultrafine-grained microstructure in a low-carbon steel under electropulsing

2002 ◽  
Vol 17 (8) ◽  
pp. 2105-2111 ◽  
Author(s):  
Yizhou Zhou ◽  
Wei Zhang ◽  
Baoquan Wang ◽  
Guanhu He ◽  
Jingdong Guo
Keyword(s):  
Carbon Steel ◽  
Grain Refinement ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
Low Carbon ◽  
Experimental Conditions ◽  
Ultrafine Grained ◽  
The Relationship ◽  
Ultrafine Grained Microstructure ◽  
A Current

High current electropulsing was applied to a low-carbon steel in the solid state. The relationship between grain size and experimental conditions was revealed. It was found that the ultrafine-grained (UFG) microstructure could be formed when electric current density, heating rate, and cooling rate all were high. The UFG samples prepared by applying electropulsing were free of porosity and contamination, and had no large microstrain. Also, their tensile strength was dramatically enhanced over that of their coarse-grained counterparts, without a decrease in ductility. The mechanism for grain refinement and formation of the UFG microstructure was discussed. It is proposed that the effect of a decrease in thermodynamic barrier and enhancement of nucleation rate in a current-carrying system cannot be neglected.

scholarly journals Dynamic Recrystallization Behavior of Twin Roll Cast Low Carbon Steel Strip

2009 ◽  
Vol 49 (4) ◽  
pp. 546-552 ◽  
Author(s):  
Haiyan Gao ◽  
Zhixiong Xie ◽  
Yan Yu ◽  
Yuan Fang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Dynamic Recrystallization ◽  
Steel Strip ◽  
Low Carbon Steel ◽  
Recrystallization Behavior ◽  
Low Carbon ◽  
Dynamic Recrystallization Behavior ◽  
Twin Roll Cast ◽  
Twin Roll

scholarly journals Low-carbon cast microalloyed steel intercritically heat-treated at different temperatures: microstructure and mechanical properties

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Hadi Torkamani ◽  
Shahram Raygan ◽  
Carlos Garcia Mateo ◽  
Yahya Palizdar ◽  
Jafar Rassizadehghani ◽  
...  
Keyword(s):  
Carbon Content ◽  
Volume Fraction ◽  
Block Size ◽  
Tensile Tests ◽  
Total Elongation ◽  
Martensite Phase ◽  
Low Carbon ◽  
Steel Increase ◽  
Different Temperatures ◽  
The Impact

AbstractIn this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed by quenching. Decreasing the IHT temperature from 800 to 750 °C leads to: (i) a decrease in the volume fraction of austenite (martensite after quenching) from 0.68 to 0.36; (ii) ~ 100 °C decrease in martensite start temperature (Ms), mainly due to the higher carbon content of austenite and its smaller grains at 750 °C; (iii) a reduction in the block size of martensite from 1.9 to 1.2 μm as measured by EBSD. Having a higher carbon content and a finer block size, the localized microhardness of martensite islands increases from 380 HV (800 °C) to 504 HV (750 °C). Moreover, despite the different volume fractions of martensite obtained in DP microstructures, the hardness of the steels remained unchanged by changing the IHT temperature (~ 234 to 238 HV). Applying lower IHT temperature (lower fraction of martensite), the impact energy even decreased from 12 to 9 J due to the brittleness of the martensite phase. The results of the tensile tests indicate that by increasing the IHT temperature, the yield and ultimate tensile strengths of the DP steel increase from 493 to 770 MPa, and from 908 to 1080 MPa, respectively, while the total elongation decreases from 9.8 to 4.5%. In contrast to the normalized sample, formation of martensite in the DP steels could eliminate the yield point phenomenon in the tensile curves, as it generates free dislocations in adjacent ferrite.

Effect of Mo Concentration on Dynamic Recrystallization Behavior of Low Carbon Microalloyed Steels

2013 ◽  
Vol 84 (12) ◽  
pp. 1191-1195 ◽  
Author(s):  
Thomas Schambron ◽  
Liang Chen ◽  
Taliah Gooch ◽  
Ali Dehghan-Manshadi ◽  
Elena V. Pereloma
Keyword(s):  
Dynamic Recrystallization ◽  
Microalloyed Steels ◽  
Recrystallization Behavior ◽  
Low Carbon ◽  
Dynamic Recrystallization Behavior ◽  
Carbon Microalloyed
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