This study examines the effect of cerium addition on the corrosion behaviour of microalloyed steel by comparing three compositions: cerium-free (WCe), low-cerium (0.015 wt.%, LCe) and high-cerium (0.045 wt.%, HCe). Corrosion resistance was evaluated through 60-day immersion tests in 3.5 wt.% NaCl solution and electrochemical measurements were supported by detailed microstructural and surface characterisations. The LCe steel exhibited superior corrosion resistance attributed to the formation of a stable and adherent cerium-rich passive oxide layer that effectively suppressed localised corrosion. In contrast, WCe showed severe surface degradation and pitting while HCe displayed the highest corrosion rate and intense localised attack due to coarse cerium-rich inclusions that disrupted passive film stability. SEM-EDS analysis confirmed that LCe developed a uniform protective oxide, whereas HCe formed heterogeneous oxide layers enriched with Mn and S, which promoted pitting. Electrochemical polarisation results further demonstrated that LCe had higher corrosion potential, lower current density and greater polarisation resistance, whereas HCe exhibited poor electrochemical performance. These findings identify 0.015 wt.% cerium as the optimal addition within the tested levels for enhancing corrosion resistance in microalloyed steel, while excessive cerium (0.045 wt.%) compromises passive film integrity and accelerates corrosion. Cette & eacute;tude examine l'effet de l'ajout de c & eacute;rium sur le comportement & agrave; la corrosion d'un acier micro-alli & eacute; en comparant trois compositions: sans c & eacute;rium (WCe), & agrave; faible teneur en c & eacute;rium (0.015% en poids, LCe) et & agrave; teneur & eacute;lev & eacute;e en c & eacute;rium (0.045% en poids, HCe). On a & eacute;valu & eacute; la r & eacute;sistance & agrave; la corrosion par des essais d'immersion de 60 jours dans une solution & agrave; 3.5% en poids de NaCl et par des mesures & eacute;lectrochimiques, compl & eacute;t & eacute;es par des caract & eacute;risations de surface et microstructurales d & eacute;taill & eacute;es. L'acier LCe pr & eacute;sentait une r & eacute;sistance & agrave; la corrosion sup & eacute;rieure, attribu & eacute;e & agrave; la formation d'une couche d'oxyde passive riche en c & eacute;rium, stable et adh & eacute;rente, qui supprimait efficacement la corrosion localis & eacute;e. En revanche, le WCe montrait une d & eacute;gradation de surface et une piq & ucirc;ration importantes tandis que le HCe pr & eacute;sentait le taux de corrosion le plus & eacute;lev & eacute; et une attaque localis & eacute;e intense en raison d'inclusions grossi & egrave;res riches en c & eacute;rium qui perturbaient la stabilit & eacute; du film passif. L'analyse par MEB-EDS a confirm & eacute; que le LCe d & eacute;veloppait un oxyde protecteur uniforme tandis que le HCe formait des couches d'oxyde h & eacute;t & eacute;rog & egrave;nes enrichies en Mn et en S, qui favorisaient la piq & ucirc;ration. Les r & eacute;sultats de polarisation & eacute;lectrochimique ont en outre d & eacute;montr & eacute; que le LCe pr & eacute;sentait un potentiel de corrosion plus & eacute;lev & eacute;, une plus faible densit & eacute; de courant et une plus grande r & eacute;sistance & agrave; la polarisation, tandis que le HCe pr & eacute;sentait de faibles performances & eacute;lectrochimiques. Ces r & eacute;sultats identifient 0.015% en poids de c & eacute;rium comme ajout optimal, parmi les niveaux & eacute;valu & eacute;s, pour am & eacute;liorer la r & eacute;sistance & agrave; la corrosion de l'acier micro-alli & eacute;, tandis qu'un exc & egrave;s de c & eacute;rium (0.045% en poids) compromet l'int & eacute;grit & eacute; du film passif et acc & eacute;l & egrave;re la corrosion.

Non-metallic inclusions in steel negatively affect operational processes and mechanical properties based on their morphology, size, physical state and distribution. Inclusion modification is especially important when sulphur levels are high because the sulphides that form can affect the operational process more significantly than the unmodified inclusions themselves. This research is an attempt to examine the impact of cerium addition on tensile and impact toughness properties, grain size, inclusion composition, morphology and fracture surface of microalloyed peritectic grade steel. The impact toughness at − 40 °C significantly increased by 139 and 164

The aim of this study is to explore the interaction behavior of slag containing 5.59 wt pct Ce2O3 with MgO-C refractory bricks at high temperature and its comparison with slag without Ce2O3. Slags under consideration were byproduct generated during steelmaking process in an induction furnace. Slag without Ce2O3 has exhibited a greater degree of penetration into the refractory material in contrast to slag containing Ce2O3. Mechanism of interaction was understood by performing thermodynamic modeling using FactSage, X-Ray diffraction analysis (XRD), and X-ray Computed Tomography (X-Ray μCT). FactSage elucidated evolution of phases during interactions at test temperature, while XRD provided insights into the phases present at room temperature after interaction. X-Ray μCT analysis revealed that the penetration depth by slag reached up to 3 mm along the brick wall in the absence of Ce2O3. However, slag containing Ce2O3 reaction depth along the wall and the bottom was 1.80 mm. Penetration by slag without Ce2O3 was mainly due to the presence of less stable oxides and liquid phase fraction, which has exhibited more vigorous reaction with MgO-C brick. Mechanism of transformative effect of Ce2O3 on low melting phases to stable and high melting rare earth phases like Vanadoandrosite ((Mn2+Ce)(V3+AlMn2+)O[Si2O7][SiO4](OH)), oxide, and sulfide has been discussed in detail.

Internal subsurface cracks in continuously cast slabs can lead to catastrophic failure of the material when it is subjected to further rolling or shaping. The interplay of multiple factors contributes to the formation of these cracks, making it occasionally challenging to accurately assess slab quality based solely on surface appearance. This paper presents an in-depth exploration of the internal quality of slabs, that aimed to identify the critical parameters responsible for initiating and propagating these cracks. The investigation employs a range of methodologies, including macro- and micro-metallographic analysis, thermo-mechanical simulations, that aid in characterizing defects and understanding material vulnerability. To prevent such failures in cast products, the study also proposes optimized operational parameters.

In current market scenario, cold-rolled steel sheets need high quality requirements to suit the continuous automated forming process for manufacturing components of diverse end applications. Deep drawability, which is one of the crucial property of steel for forming application, is influenced by factors like alloy chemistry, microstructure, texture evolution and precipitation characteristics. All these microstructural factors are in turn affected directly by the annealing process employed. In the present study, specially designed continuous annealing process has been employed to assess the influence of boron to nitrogen (B/N) ratio (0–0.87)on mechanical and drawing properties of low carbon (0.03–0.035 wt %), low manganese (0.15–0.18 wt%) and low sulphur (0.005–0.008 wt%) steel. Steel with B/N ratio of 0.185resulted into best combination of properties in terms of lowest YS/UTS ratio (0.81),high plastic anisotropy (rm:1.545) along with 310 MPa yield strength, 380 MPa ultimate tensile strength, 20% uniform elongation and 32% total elongation. It has been found that the B/N ratio, rather than the absolute boron, influences the precipitation characteristics of carbides and favorable texture development during continuous annealing process.

Clogging of sub entry nozzle is a recurrent problem during continuous casting of low carbon aluminum deoxidized steel. Newly modernized SMS shop, producing mainly low carbon aluminum deoxidized steel through BOF-Twin LF-CC route was facing a major issue of nozzle clogging leading to abrupt abortion of sequence casting. The incidences of SEN clogging were very high leading to loss of shop productivity. Within a span of one month around 28 cases of casting abortion were reported due SEN clogging. Casting was getting stopped in 3–4 heat sequence even after calcium treatment practice was adopted in each heat. The process of steelmaking was studied in detail to find out the root cause of nozzle clogging. It was found that dendritic clusters of alumina originating as a result of deoxidation of steel and reoxidation of aluminum during secondary refining was probably causing SEN clogging. It was also found that optimization of Ca treatment practice was required for successful continuous casting of an aluminum-killed steel. The paper elaborates the technical issues faced related to clogging of SEN in a newly installed high speed single strand slab caster during continuous casting of low carbon steel deoxidized with aluminum. The paper covers the essential steps required to identify the root cause of nozzle clogging and various process interventions essential to eliminate the SEN clogging issues and streamline the production of low carbon aluminum-killed steel in higher sequence lengths.

Anisotropy in texture determines capacity of the steel to achieve maximum plastic flow in the plane of the sheet and maximum resistance to flow in a direction perpendicular to the sheet. Present work has been carried out to explore the potential of maximizing plastic anisotropy (rm) value in extra deep-drawing steel. Industrial heat was made with low carbon (0.03 wt.%), low manganese (0.15 wt.%), and low sulfur (0.007 wt.%) levels. Continuously cast slabs were hot-rolled and then cold-rolled to 1 mm thickness. The cold-rolled sheets were subsequently subjected to annealing in an annealing simulator furnace adopting specially designed two-stage batch annealing cycle. In batch-annealed steel samples, grains were found to be recrystallized and had undergone grain growth preferentially along the longitudinal direction with strong gamma fiber, comparable to that of Interstitial Free steel. Excellent combination of strength and forming properties, in terms of yield strength 190 MPa, ultimate tensile strength 290 MPa, and total elongation 45%, YS/UTS: − 0.66 with very high plastic anisotropy (rm): 2.45, could be achieved. Properties achieved have been correlated with the alloy chemistry, processing path history, percentage reduction, two-stage batch annealing cycle and the resultant grain size, microstructure and texture.

High-strength formable quality (HSFQ) steel grades, steel A (0.038Nb, 0.031Si), steel B (0.034 Nb, 0.27Si), and steel C (0.044Nb, 0.26Si), with varying Nb and Si content has been investigated. The microstructure, texture, precipitation, mechanical properties and corrosion behavior of these steel grades have been explored. Very fine grain size in the range of 2.7-3.6 µm was obtained in all these steel grades through controlled hot rolling. However, a significant variation in the crystallographic texture and precipitation behavior in these steels was observed. A higher volume fraction of γ-fiber texture components and uniformly distributed fine Nb(C, N) precipitates were obtained in steel B as compared to steel A and C. This resulted in better properties in steel B with relatively high PSE (product of strength–elongation), high uniform elongation, and high hole expansion ratio. The corrosion properties of the steels were also evaluated, and steel B showed better corrosion resistance among the three grades. Considering the overall performance and properties of these steel grades, steel B with an optimum Nb and Si content is found to have better property and performance among the three grades.

In a steel plant, basic oxygen furnace (BOF) is a method to convert liquid hot metal and steel scrap into steel with oxidizing action of oxygen blowing into the melt. A water-cooled lance is used for blowing of pure gaseous oxygen (> 99.5%) at high pressure and flow rate of 11–13 kg/cm2 and ~ 1000 Nm3/min, respectively. A failure of BOF lance head assembly occurred in one of the integrated steel plants. A small oxygen leak ignited near the flange and a significant portion of the oxygen pipe elbow was consumed. The failure analysis was carried out, and likely reasons for the failure were identified. During the BOF process, oxygen is blown at high velocity into molten, carbon-saturated hot metal as received from blast furnaces. Oxygen reacts with carbon to form carbon monoxide (CO) and carbon dioxide (CO2) gases, among other reactions. The occurrence of flames, metal spitting and post-combustion of CO gas generates high-temperature conditions that can damage the oxygen lance assembly. They can also cause changes in microstructure of the parent material (low-carbon-grade SS310S) of the elbow and weaken the material over a period of time. It was found that the presence of a minute puncture in the oxygen pipe line may, under thermodynamically favorable conditions, ignite the leaking oxygen. Such a minute leakage may have occurred due to failure of material, weld joint or detachable joint.

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India.

Fuel cost, dwindling resources, and exponentially increasing traffic density have brought about a sea change in thinking of automotive designers, manufacturers, and end users. Though number of recently developed advanced high-strength steels fulfill the expectation of automobile component manufacturers in terms of weight reduction and safety norms, it suffers the inherent problem of spring back phenomena and limited formability. This problem can be addressed if the component is formed at high temperature where it has adequate formability and subsequently it is controlled cooled to get the desired combination of strength and ductility; the process is commonly known as hot stamping. As C (0.2–0.3 wt%)- Mn (1.2–1.3%)- Cr (0.1–0.2 wt%)- B (25–35 ppm) alloyed steels have been the point of focus for the choice of materials in hot stamping, study has been carried out on effect of concurrent deformation and cooling on hardening behavior and associated microstructural changes of C–Mn–Cr–B steel. Further, effect of molybdenum (~0.1 wt%) in influencing the microstructure and thereby hardening in conventional C–Mn–Cr–B steels has also been evaluated. The present study reveals that a range of tailored properties can be achieved through locally controlling strain, strain rate, cooling rate, and resultant microstructure within the stamping die.

The present work was carried out to understand effect of boron to nitrogen ratio and the different quenching media in low carbon low manganese unalloyed steel. Tensile samples of hot rolled sheets were heat treated in laboratory muffle furnace to 890°C and quenched in oil and water. Mechanical properties and microstructure of quenched samples were analysed. A decreasing trend of YS/UTS ratio observed after quenching irrespective of the quenching media. It has been observed that boron and cooling rate in combination improves the hardenability and increase the UTS value. Boron played an important role in contributing microstructure evolution with different quenching media and thereby resulted excellent combination of properties in cost effective low carbon unalloyed steel. Good combination of properties observed in water quenched as well as oil quenched steel samples with low B/N ratio. Quenched samples were further normalized at 920°C and properties were compared with as rolled boron free steel and results shows improvement in properties in terms of lower YS/UTS value with boron addition. The reason behind may be formation of contributing phases which are retained in the microstructure even after normalizing. Drop in strength values when compared with properties of low carbon boron added hot rolled steel revealed more drop in case of water quenching than that of oil quenching.

Abstract This article provides a detailed discussion on the effect of boron in heat-treated steel and thermomechanically-simulated steel. It describes the boron hardenability mechanism and the effect of composition and heat treatment parameters on boron hardenability. The article examines the hardening behavior of unalloyed boron steel and low-alloyed boron steel in heat treatment experiments by varying the austenitizing temperatures and cooling conditions. It also discusses the applications of boron steels.

Three steels viz., G22(Fe-0.072C-0.028 Si-0.20Mn-0.19P-0.38Cr-0.24Cu-0.17Ni), G32(Fe-0.072C-0.061 Si-0.23 Mn-0.19P-0.64Cr-0.14Cu) and SCOR (Fe-0.09C-0.37Si-0.42Mn-0.15P-0.37Cr-0.35Cu-0.31Ni) were made through ingot metallurgy route and hot rolled to 3 mm thick sheets. Tafel extrapolation study of freshly ground samples in 3.5% NaCl solution revealed similar corrosion rates for all steels. Another technique employed to evaluate the effect of phosphorus on the formation of protective rust layer was electrochemical impedance spectroscopy (EIS) test after exposing the samples in an atmospheric exposure rack for four months on the roof top of a fourth floor building. Results revealed that the polarization resistance or rust resistance of G22 and SCOR steels was comparable and similar to that of a reference steel SAILCOR (Fe-0.07C-0.48Si-0.31Mn-0.118P-0.41Cr-0.32Cu-0.21Ni), which is produced at Bokaro Steel plant. The role of phosphorus in improving atmospheric corrosion resistance was understood from this study.

High strength IS 2062 E410 grade structural were being produced at ISP by micro alloying with Nb (0.03-0.04%). To circumvent higher mill load experienced during rolling (Finish Rolling Temperature 850°-900℃), Nb was substituted by V (0.03-0.04%). Further to develop high tensile structural with leaner chemistry, addition of less Nb (~0.01%) and higher silicon (~0.20%) was tried to reduce the cost of production without sacrificing the properties. Successfully rolled material reveals that ferrite grain size with lower Nb and Si was found to be comparable with that of higher Nb steel and finer than that of V bearing steel. Synergistic effect of silicon in presence of niobium has resulted in refinement of grain size.