Model Prediction on the Behavior of Cerium in Heavy Rail Steel

2011 ◽  
Vol 255-260 ◽  
pp. 3984-3987
Author(s):  
Cheng Jun Liu ◽  
Hong Liang Liu ◽  
Mao Fa Jiang
Keyword(s):  
Model Prediction ◽  
Thermodynamic Model ◽  
Rail Steel ◽  
Necessary Condition ◽  
Cerium Content ◽  
Heavy Rail ◽  
Transformation Condition ◽  
Heavy Rail Steel

The thermodynamic model which quantificationally described the behavior of cerium in heavy rail steel was proposed. From the model, the effects of cerium on the composition, sequence and transformation condition of inclusions and the content of cerium dissolved in heavy rail steel were studied principally. When the cleanliness of heavy rail steel is low, the sequence of inclusions precipitation in heavy rail steel is Ce2O3, Ce2O2S, Ce2S3 and CeS. With increasing the cleanliness of steel, the sequence of inclusions precipitation is Ce2O2S and CeS. At 1783 K, the necessary condition of Ce2O3 precipitation in heavy rail steel is ao/as≥0.186, for Ce2S3 precipitation is ao/as≤0.394. The content of cerium dissolved in heavy rail steel is mainly affected by Ce2S3 inclusion. With the precipitations of all inclusions being stable, the curve between the dissolved cerium content and cerium addition becomes linear.

scholarly journals A thermodynamic assessment of precipitation, growth, and control of MnS inclusion in U75V heavy rail steel

2021 ◽  
Vol 40 (1) ◽  
pp. 178-192
Author(s):  
Wen-Qiang Ren ◽  
Lu Wang ◽  
Zheng-Liang Xue ◽  
Cheng-Zhi Li ◽  
Hang-Yu Zhu ◽  
...  
Keyword(s):  
Particle Size ◽  
Rail Steel ◽  
Solidification Process ◽  
Segregation Ratio ◽  
Two Phase ◽  
Final Particle ◽  
Solid Liquid ◽  
And Control ◽  
Heavy Rail ◽  
Heavy Rail Steel

Abstract Thermodynamic analysis of the precipitation behavior, growth kinetic, and control mechanism of MnS inclusion in U75V heavy rail steel was conducted in this study. The results showed that solute element S had a much higher segregation ratio than that of Mn, and MnS would only precipitate in the solid–liquid (two-phase) regions at the late stage during the solidification process at the solid fraction of 0.9518. Increasing the cooling rate had no obvious influence on the precipitation time of MnS inclusion; however, its particle size would be decreased greatly. The results also suggested that increasing the concentration of Mn would lead to an earlier precipitation time of MnS, while it had little effect on the final particle size; as to S, it was found that increasing its concentration could not only make the precipitation time earlier but also make the particle size larger. Adding a certain amount of Ti additive could improve the mechanical properties of U75V heavy rail steel due to the formation of TiO x –MnS or MnS–TiS complex inclusions. The precipitation sequences of Ti3O5 → Ti2O3 → TiO2 → TiO → MnS → TiS for Ti treatment were determined based on the thermodynamic calculation.

Effects of Rare Earths on Structural Transformation of Heavy Rail Steel

2011 ◽  
Vol 194-196 ◽  
pp. 237-242
Author(s):  
Cheng Jun Liu ◽  
Ya He Huang ◽  
Mao Fa Jiang
Keyword(s):  
Cooling Rate ◽  
Incubation Period ◽  
Rare Earths ◽  
Rail Steel ◽  
Vacuum Induction Furnace ◽  
Critical Cooling Rate ◽  
The Stability ◽  
Heavy Rail ◽  
Electronic Microscope ◽  
Heavy Rail Steel

Clean heavy rail steel was prepared by the process of vacuum induction furnace smelting, forge work and rolling. Effects of Rare earths (RE) on phase transformation and microstructure of heavy rail steel were investigated by thermal simulation machine, metallographic microscope and scanning electronic microscope. Thermal simulate tests indicate that, RE can move the C curve of pearlite transformation to lower right, prolong the incubation period of pearlite and improve the stability of undercooled austenite. The minimum incubation period of pearlite transformation is increased from 24s to 30s by RE. Furthermore, RE can decrease the critical cooling rate of pearlite transformation from 1°C•s-1to 0.5°C•s-1and the critical cooling rate of quenching from 15°C•s-1to 13°C•s-1. Additionally, RE can fine the annealing and anormalizing pearlite notably. The pearlite laminae distance of heavy rail steel added RE is decreased by 12.9% (annealing) and 13.3% (normalizing), respectively.

scholarly journals Prediction on the spatial distribution of the composition of inclusions in a heavy rail steel continuous casting bloom

2020 ◽  
Vol 9 (3) ◽  
pp. 5648-5665 ◽  
Author(s):  
Qiang Ren ◽  
Yuexin Zhang ◽  
Lifeng Zhang ◽  
Jujin Wang ◽  
Yanping Chu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Continuous Casting ◽  
Rail Steel ◽  
Steel Continuous Casting ◽  
Heavy Rail ◽  
Heavy Rail Steel

Effects of Cooling on Bending Process of Heavy Rail Steel After Hot Rolling

2016 ◽  
Vol 5 (3) ◽  
pp. 196-206 ◽  
Author(s):  
Lin Chen ◽  
Min Yang ◽  
Yunchao Xu ◽  
Zhiyang Zhang ◽  
Zeyuan Li ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Rail Steel ◽  
Bending Process ◽  
Heavy Rail ◽  
Heavy Rail Steel

Effects and Mechanisms of Niobium on the Fracture Toughness of Heavy Rail Steel

2010 ◽  
Vol 163-167 ◽  
pp. 110-116 ◽  
Author(s):  
Cheng Jun Liu ◽  
Ya He Huang ◽  
Hong Liang Liu ◽  
Mao Fa Jiang
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Crack Growth ◽  
Rail Steel ◽  
Vacuum Induction Furnace ◽  
Austenite Grain Size ◽  
Niobium Content ◽  
Austenite Grain ◽  
Heavy Rail ◽  
Heavy Rail Steel

Heavy rail steel was prepared by the process of vacuum induction furnace smelting, forge work and rolling. Effects and mechanisms of niobium on the fracture toughness of heavy rail steel were investigated. In addition, the appropriate range of niobium content for heavy rail steel was determined. With the niobium content increasing, both the austenite grain size and pearlite laminae distance of heavy rail steel were decreased gradually at first and then increased rapidly. When the niobium content was low, the precipitates containing niobium predominantly appeared in the cementite, which improved the toughness of heavy rail steel by fining the austenite grain size and pearlite laminae distance; when the niobium content > 0.024%, the fine dispersed precipitates containing niobium mainly occurred in the ferrite, which improved the toughness of heavy rail steel by pining dislocations and inhibiting crack growth; with the niobium content increasing, both the quantity and size of precipitates containing niobium were increased gradually; when the niobium content > 0.073%, most precipitates containing niobium could not pin dislocations and inhibit crack growth because the particles size was too big, thus the fracture toughness of heavy rail steel was bad. So the optimum range of the niobium content could improve the fracture toughness of heavy rail steel. In the present study, when the niobium content was about 0.053%, the fracture toughness of heavy rail steel was the best. The maximum plane-strain fracture toughness was 49.88 MPam1/2.

Effects and Mechanisms of Vanadium on Structural Transformation of BVRE Heavy Rail Steel

2010 ◽  
Vol 146-147 ◽  
pp. 1216-1221 ◽  
Author(s):  
Ya He Huang ◽  
Cheng Jun Liu ◽  
Mao Fa Jiang
Keyword(s):  
Cooling Rate ◽  
Martensite Transformation ◽  
Rail Steel ◽  
Vanadium Content ◽  
Metallographic Analysis ◽  
Continuous Cooling ◽  
Cct Curve ◽  
The Stability ◽  
Heavy Rail ◽  
Heavy Rail Steel

The different dilatometric curves of continuous cooling transformation with the different cooling rates were determined by means of Gleeble-2000 thermal simulation machine. The CCT curve of BVRE heavy rail steel was obtained by measuring the dilatometric curves and metallographic analysis. And the effects and mechanisms of vanadium on the phase transformation and microstructure of BVRE heavy rail steel were investigated. It is found that, the BVRE heavy rail steel only takes place pearlite and martensite transformation during continuous cooling. The CCT curve of BVRE heavy rail steel is moved to lower right with increasing vanadium content, which indicates that vanadium can obviously improve the stability of super cooled austenite and delay the pearlite transformation. When the content of vanadium is increased from 0.052% to 0.12%, the shortest incubation time of pearlite transformation is increased from 30s to 59s. When the cooling rate ≤ 5 ·s-1, with increasing vanadium content, both starting and finishing temperatures of pearlite transformation are decreased at different extent, meanwhile the pearlite is refined and the pearlite percentage is notably decreased. When the cooling rate is 2 ·s-1, the pearlite percentage is decreased from 65.7% to 35.9% with increasing vanadium content. When the content of vanadium is increased from 0.052% to 0.12%, the critical cooling rate of quenching is decreased from 13 ·s-1 to 7 ·s-1, thus the hardenability of BVRE heavy rail steel is improved.

Corrosion Behaviors of U75V, U76CrRE Heavy Rail Steel in Simulated Industrial Atmosphere

2013 ◽  
Vol 433-435 ◽  
pp. 2031-2037 ◽  
Author(s):  
Xiao Li Wang ◽  
Bo Song ◽  
Yang Bing Li ◽  
Sheng Li An ◽  
Jun Peng ◽  
...  
Keyword(s):  
Rail Steel ◽  
Rust Layer ◽  
Testing Technique ◽  
Corrosive Media ◽  
Corrosion Behaviors ◽  
Rapid Generation ◽  
Chemical Testing ◽  
Heavy Rail ◽  
Industrial Atmosphere ◽  
Heavy Rail Steel

The corrosion of heavy rail steel is severity in south. Now there are not studies on the corrosion of heavy rail steel in atmosphere. The corrosion of heavy rail steel were studied by periodic infiltration corrosion test and electro-chemical testing technique in simulated industrial atmosphere. The result showed that U76CrRE has apparently more excellent anti-corrosion ability than that of steel U75V. The Cr and Re in U76CrRE enriched in local of base that promotes the rapid generation of α FeOOH and the increase of content. Thus the ability of the rust layer against the corrosive media from entering the layer was improved. Anti-corrosion capacity of heavy railroad steel in industrial atmosphere can be improved significantly by adding Cr and RE alloy.

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