scholarly journals Simulation of the Refining Process of Ultra-Low Carbon (ULC) Steel

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 893
Author(s):  
Dali You ◽  
Christian Bernhard ◽  
Andreas Viertauer ◽  
Bernd Linzer

The standard production route for mild steels for automotive purposes is still based on conventional continuous casting (CC) and hot strip rolling (HSR). The current trend towards the "zero-carbon car" will demand the abating of material emissions in the future. Thin slab casting and direct rolling (e.g., Arvedi endless strip production (ESP)) is an approach to reduce CO2 emissions by 50% compared to CC and HSR. One of the main limitations in applying ESP for the production of ultra-low carbon/interstitial free (ULC/IF) steels is clogging. Clogging is the blockage of the submerged entry nozzle due to the build-up of oxide layers or an oxide network. The high clogging sensitivity of IF steels results most probably from the FeTi addition, and hence, a general change of the deoxidation practice might be an option to overcome these problems. In the present work, the thorough refining process of ULC steel was simulated by addressing the different deoxidation routes and the influence of titanium (Ti) alloying on steel cleanness. The developed ladle furnace (LF) and the Ruhrstahl Heraeus (RH) refining models were applied to perform the simulation. Before the simulations, the models are briefly described and validated by the published industrial data.

Author(s):  
Masayoshi SUEHIRO ◽  
Kazuaki SATO ◽  
Yasushi TSUKANO ◽  
Hiroshi YADA ◽  
Takehide SENUMA ◽  
...  

2012 ◽  
Vol 472-475 ◽  
pp. 622-625 ◽  
Author(s):  
Xiang Long Yu ◽  
Dong Bin Wei ◽  
Xiao Dong Wang ◽  
Zheng Yi Jiang

An experimental method was developed to study the adherence properties of the oxide scale formed on microalloyed low carbon steel after hot strip rolling. The evolution of the oxide scale during laminar cooling was investigated using Gleeble 3500 Thermal-Mechanical Simulator connected with a humid air generator. After the sample cooled down to ambient temperature, the oxide scale was protected by lacquer to prevent the scale from losing. Physicochemical characteristics of the oxide scale were examined and the adherence mechanism was discussed. Decomposed wustite a mixture of α-iron and magnetite (Fe3O4), can substantially improve the integrity of oxide scale. However, large quantities of hematite (Fe2O3) or retained wustite (FeO) were found detrimental to the adhesion of the oxide scale. It is found that the adherence of oxide scales significantly depends on the phase composition of oxide scales with different thickness.


2005 ◽  
Vol 500-501 ◽  
pp. 253-260 ◽  
Author(s):  
Christian Klinkenberg ◽  
K.-E. Hensger

The use of thin slab casting and direct rolling is well suited for the production of niobium microalloyed low-carbon high strength linepipe grades. The slabs have excellent surface quality. Thermomechanical processing by controlling hot work hardening and softening processes of austenite and its polymorphic transformation into ferrite results in a powerful microstructure refinement. This is a sound basis for setting high strength, combined with excellent ductility and toughness.


2010 ◽  
Vol 654-656 ◽  
pp. 62-65 ◽  
Author(s):  
Cheng Liang Miao ◽  
Guo Dong Zhang ◽  
Cheng Jia Shang

Compressive deformation behaviors of low carbon steels with different Nb contents were investigated in the temperature range 900oC to 1100oC and strain rates from 0.05s-1 to 2s-1 by single pass deformation. Multi-pass compressive deformation processes were also carried out to examine strain accumulation under different Nb contents. In single pass deformations, dynamic recrystallization (DRX) can be observed in the case of low strain rate and high temperature, and the higher Nb steel exhibits higher deformation activation energy (Qdef) and critical strain value (εc) for the onset of DRX. However during multi-pass compression process (interval time of 3-4s), the higher Nb steel has larger strain accumulation between passes, so it is easier for high Nb steel that DRX happens during hot strip rolling process, which starts at relative high rolling temperature.


2008 ◽  
Vol 48 (3) ◽  
pp. 344-349 ◽  
Author(s):  
Yoshinao Kobayashi ◽  
Satoshi Iwasaki ◽  
Koji Nakazato ◽  
Takaaki Hibaru ◽  
Shuuji Kuroda ◽  
...  

2012 ◽  
Vol 710 ◽  
pp. 149-154 ◽  
Author(s):  
Subrata Mallik ◽  
Biswasi Sunita Minz ◽  
Basudev Mishra

Low alloy steels are an attractive option for high performance structural applications due to cost and availability factors. A low carbon low alloyed steel, DMR 249A, was developed for strategic applications by Indian Navy at Steel Melting Shop II, Bokaro Steel Plant (SMS II, BSL). This paper enumerates the detail process variables modified for this development. DMR 249A grade was having the specified gas contents of hydrogen <2 ppm in final product for the avoidance of detrimental phenomenon like “Hair Line Cracks”. So the Hydrogen content of liquid steel was to be less than 3 ppm and this demand vacuum treatment of the steel. In absence of any Degassing unit at SMS II, BSL, making of DMR 249A steel was a challenging task. The hydrogen content of steel was controlled through restriction of hydrogen in input raw materials, control in degree of deoxidation during tapping, slag basicity at ladle furnace, argon rinsing regime and cooling of slabs i.e. control over diffusion of H2. The steel was produced with the existing infrastructure at Bokaro Steel Plant with various alloying elements and processed suitably to obtain the desired yield strength, toughness and gaseous content. The control was exercised at various stages of steel making and hot strip rolling to enable achievement of a higher degree of consistency in mechanical properties and microstructure. Quality fulfillment was a great challenge without vacuum degasser unit but Bokaro successfully made the steel with 100% customer satisfaction.


2011 ◽  
Vol 415-417 ◽  
pp. 853-858 ◽  
Author(s):  
Xiang Long Yu ◽  
Zheng Yi Jiang ◽  
Xiao Dong Wang ◽  
Dong Bin Wei ◽  
Quan Yang

The influence of the coiling temperature, ranging from 550 to 570°C, on the morphology and the phase composition of the oxide scale formed on the microalloyed low carbon steel for automobiles after hot strip rolling was investigated. Physicochemical characteristics of the oxide scales were examined and their formation mechanism was discussed. Thickness of the oxide scale is in the range of 8-11µm and decreases with a decrease of coiling temperature. The microstructure and phase composition, XRD analysis shows a large amount of magnetite (Fe3O4) and some sparse hematite (Fe2O3) exist on the surface of hot rolled strip when the coiling temperature reduces from 570 to 550°C. The coiling temperature substantially affects the internal microstructure and magnetite phase.


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