Effects of Mn and Al on the Intragranular Acicular Ferrite Formation in Rare Earth Treated C–Mn Steel

2017 ◽  
Vol 36 (7) ◽  
pp. 683-691 ◽  
Author(s):  
Mingming Song ◽  
Bo Song ◽  
Zhanbing Yang ◽  
Shenghua Zhang ◽  
Chunlin Hu
Keyword(s):  
Rare Earth ◽  
Acicular Ferrite ◽  
Lattice Misfit ◽  
Ferrite Formation ◽  
Al Content ◽  
Bainite Structure ◽  
Mn Content ◽  
Intragranular Acicular Ferrite ◽  
Upper Bainite ◽  
Mn Steel

AbstractThe influence of Al, Mn and rare earth (RE) on microstructure of C–Mn steel was investigated. The capacities of different RE inclusions to induce intragranular acicular ferrite (AF) formation were compared. Result shows that RE treatment could make C–Mn steel from large amounts of intragranular AF. Al killed is detrimental to the formation of intragranular AF in RE-treated C–Mn steel. An upper bainite structure would replace the AF when Al content increased to 0.027 mass %. The optimal Mn content to form AF is about 0.75–1.31 mass %. The effective RE inclusion which could induce AF nucleation is La2O2S. When patches of MnS are attached on the surface of La2O2S inclusion, AF nucleation capacity of RE-containing inclusion could enlarge obviously. The existence of manganese-depleted zone and low lattice misfit would be the main reason of La-containing inclusion inducing AF nucleation in C–Mn steel.

scholarly journals The Microstructure and Property of the Heat Affected zone in C-Mn Steel Treated by Rare Earth

2019 ◽  
Vol 38 (2019) ◽  
pp. 362-369 ◽  
Author(s):  
Ming-ming Song ◽  
Yu-min Xie ◽  
Bo Song ◽  
Zheng-liang Xue ◽  
Nan Nie ◽  
...  
Keyword(s):  
Rare Earth ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
Steel Matrix ◽  
Impact Properties ◽  
Treated Steel ◽  
The Impact ◽  
Welding Processes ◽  
Mn Steel

AbstractThe microstructures and impact properties of the heat affected zone (HAZ) in steel treated by rare earth (RE) under different welding processes were discussed. The effect of Al on the impact properties of the HAZ in RE treated steel was analyzed. It finds that when the welding t8/5 is smaller than 111 s, the main microstructure in steels is bainite/widmanstatten. The impact toughness of the HAZ is lower than that of the steel matrix. When t8/5 is more than 250 s, the microstructure is mainly acicular ferrite (AF) in the steel treated by RE, and the impact toughness of HAZ is obviously improved. Even under the welding processing with t8/5 about 600 s in RE treated steel can still obtain a lot of AF. While in the steel killed by Al and treated by RE, the main microstructure is parallel cluster of bainite/widmanstatten, and the impact toughness of HAZ is significantly lower than that of low-Al RE treated steel. Al can deteriorate the optimizing of RE treatment on HAZ.

scholarly journals Acicular Ferrite Formation on Ti-Rare Earth Metal-Zr Complex Oxides

2015 ◽  
Vol 55 (1) ◽  
pp. 250-256 ◽  
Author(s):  
Hidenori Nako ◽  
Yoshitomi Okazaki ◽  
John Gordon Speer
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Acicular Ferrite ◽  
Earth Metal ◽  
Complex Oxides ◽  
Ferrite Formation

Effects of Si and Al on acicular ferrite formation in C-Mn steel

2001 ◽  
Vol 32 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Jae-Hyeok Shim ◽  
Young Whan Cho ◽  
Jae-Dong Shim ◽  
Young-Joo Oh ◽  
Jung-Soo Byun ◽  
...  
Keyword(s):  
Acicular Ferrite ◽  
Ferrite Formation ◽  
Mn Steel

Evolution of inclusions in Mg-RE-Ti treated steels with different Al contents and their influence on acicular ferrite

2021 ◽  
Vol 118 (2) ◽  
pp. 208
Author(s):  
Xiaokang Cui ◽  
Bo Song ◽  
Jinghong Mao
Keyword(s):  
Size Distribution ◽  
Acicular Ferrite ◽  
Lattice Misfit ◽  
Al Content ◽  
Layer Structures ◽  
La Addition

The size distribution and composition of inclusions in Mg-RE-Ti treated steels with different Al contents were investigated systematically, while the microstructure and the nucleation potency of inclusions for AF were analyzed. The results show that the inclusions were refined with Mg treatment, and then coarsen following La addition in the samples. The particles in high Al sample were more likely to collide, aggregate and form clusters due to the relatively high amount of inclusions in melt steel. The dominate inclusions were composed of two layer structures with Mg-bearing inclusions cores and La-bearing inclusions shells. With the increase of Al content, the cores evolved from MgO to MgO•Al2O3 and the shells evolved from La2O2S and La2O3 to LaAlO3. The nucleation potency of inclusions for AF decreased due to relatively high lattice misfit between inclusions and α-Fe in high Al sample. The AF fraction decreased with the increase of Al content because of the decrease of the amount of effective inclusions.

Effects of Ti-Al Complex Deoxidization Inclusions on Nucleation of Intragranular Acicular Ferrite in C-Mn Steel

2015 ◽  
Vol 87 (4) ◽  
pp. 445-455 ◽  
Author(s):  
Qi Huang ◽  
Xinhua Wang ◽  
Min Jiang ◽  
Zhiyong Hu ◽  
Chengwei Yang
Keyword(s):  
Acicular Ferrite ◽  
Intragranular Acicular Ferrite ◽  
Mn Steel

Improvement of hot ductility of C-Mn Steel containing arsenic by rare earth Ce

2018 ◽  
Vol 115 (4) ◽  
pp. 419 ◽  
Author(s):  
Wenbin Xin ◽  
Jing Zhang ◽  
Guoping Luo ◽  
Ruifen Wang ◽  
Qingyong Meng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Boundary Segregation ◽  
Fracture Morphology ◽  
Grain Boundary Segregation ◽  
Hot Ductility ◽  
Ductility Trough ◽  
Reduction Of Area ◽  
Mn Steel ◽  
Ce Content

The effect of different Ce content on the hot ductility of C-Mn steel containing arsenic was investigated at the temperature ranging from 700 to 1100 °C conducting Gleebel-1500 thermal-mechanical simulator. The reduction of area (RA%) was used to evaluate the hot ductility. The 0.16 mass% As widened the ductility trough range and especially, decreased the RA value at 850–950 °C. Conversely, adding Ce in the steel could remedy the arsenic-induced hot ductility deterioration. Moreover, with the increase of Ce content from 0 to 0.035 mass%, the RA value at 800–950 °C significantly increased, compared to that of the arsenic steel. When the content of Ce reached 0.027–0.035 mass%, the RA value at 800–850 °C was even higher than that of steel without As. Besides, the corresponding fracture morphology was changed from intergranular feature to ductile and/or interdendritic feature. Grain refinement by Ce addition, the formation of arsenious rare earth inclusions and grain boundary segregation of Ce were considered to improve the hot ductility of the steel containing As.

scholarly journals Characterization of Microstructure in High-Hardness Surface Layer of Low-Carbon Steel

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 995
Author(s):  
Haitao Xiao ◽  
Shaobo Zheng ◽  
Yan Xin ◽  
Jiali Xu ◽  
Ke Han ◽  
...  
Keyword(s):  
Surface Layer ◽  
Carbon Steel ◽  
Yield Strength ◽  
Carbon Content ◽  
Acicular Ferrite ◽  
Lath Martensite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Upper Bainite ◽  
Mixed Microstructure

Surface hardening improves the strength of low-carbon steel without interfering with the toughness of its core. In this study, we focused on the microstructure in the surface layer (0–200 μm) of our low-carbon steel, where we discovered an unexpectedly high level of hardness. We confirmed the presence of not only upper bainite and acicular ferrite but also lath martensite in the hard surface layer. In area of 0–50 μm, a mixed microstructure of lath martensite and B1 upper bainite was formed as a result of high cooling rate (about 50–100 K/s). In area of 50–200 μm, a mixed microstructure of acicular ferrite and B2 upper bainite was formed. The average nanohardness of the martensite was as high as 9.87 ± 0.51 GPa, which was equivalent to the level reported for steel with twenty times the carbon content. The ultrafine laths with an average width of 128 nm was considered to be a key cause of high nanohardness. The average nanohardness of the ferrites was much lower than for martensite: 4.18 ± 0.39 GPa for upper bainite and 2.93 ± 0.30 GPa for acicular ferrite. Yield strength, likewise, was much higher for martensite (2378 ± 123 MPa) than for upper bainite (1007 ± 94 MPa) or acicular ferrite (706 ± 72 MPa). The high yield strength value of martensite gave the surface layer an exceptional resistance to abrasion to a degree that would be unachievable without additional heat treatment in other steels with similar carbon content.

Acicular ferrite formation during isothermal holding in HSLA steel

2015 ◽  
Vol 51 (7) ◽  
pp. 3555-3563 ◽  
Author(s):  
Chenxi Liu ◽  
Lei Shi ◽  
Yongchang Liu ◽  
Chong Li ◽  
Huijun Li ◽  
...  
Keyword(s):  
Acicular Ferrite ◽  
Hsla Steel ◽  
Isothermal Holding ◽  
Ferrite Formation
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