Inclusions In Carbon Steel Research Articles

Investigation of Scaling and Materials' Performance in Simulated Geothermal Brine.

Geothermal energy generation faces challenges in efficiency, partly due to restrictions on reinjection temperatures caused by scaling issues. Therefore, developing strategies to prevent scaling is critical. This study aims to simulate the scaling tendencies and corrosion effects of geothermal fluids on various construction materials used in scaling reactor/retention tank systems. A range of materials, including carbon steel, austenitic stainless steel, duplex stainless steel, two proprietary two-part epoxy coatings, and thermally sprayed aluminium (TSA), were tested in a simulated geothermal brine. Experiments were conducted in a laboratory vessel designed to replicate the wall shear stress conditions expected in a scaling reactor. The tests revealed varying scaling tendencies among the materials, with minimal corrosion observed. The dominant scale formed was calcium carbonate, consistent with geochemical modelling. The findings suggest that despite the high operating temperatures, the risk of corrosion remains low due to the brine's low chloride content, while the wettability of materials after immersion may serve as a useful indicator for selecting those that promote scaling.

Effects of substrate materials and electrodeposition parameters on hydrogen evolution reaction of Ni–Cu–Fe coatings

In this study, the effects of substrate materials and electrodeposition parameters on the hydrogen evolution reaction (HER) of Ni–Cu–Fe coatings were studied. For this purpose, different materials, including carbon steel (CS), stainless steel 304 (SS), and pure commercial graphite (G) were used as substrates, while the coating process was done in both modes of constant current density (CC) and variable current density, the latter to produce a functionally-graded (FG) coating. Microstructural investigations were done by using scanning electron microscopy, while the HER behavior was analyzed by electrochemical tests, including cyclic voltammetry (CV), linear scanning voltammetry (LSV), and electrochemical impedance (EIS) measurements. The morphology of the produced Ni–Cu–Fe coatings was completely affected by the coating parameters in the deposition bath and the type of substrates. In samples with micro/nano-cone morphology, deposited at a constant current density of 2.5 A/dm2, better HER behavior was obtained due to the highly effective surface and easier separation of hydrogen bubbles. Besides, the best electrocatalytic activity and the lowest overpotential (110 mV at 10 mA/cm2 in CC mode) were related to the samples coated on G. The proper selection of the substrate material plays an important role in improving the electrocatalytic behavior of composite coatings.

Exploring the mechanisms of calcium carbonate deposition on various substrates with implications for effective anti-scaling material selection

The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries, leading to issues such as heat exchanger failures and pipeline clogging. It is of practical and fundamental importance to understand the scaling mechanisms and develop efficient anti-scaling strategies. However, the underlying surface interaction mechanisms of scalants (e.g., calcite) with various substrates are still not fully understood. In this work, the colloidal probe atomic force microscopy (AFM) technique has been applied to directly quantify the surface forces between calcite particles and different metallic substrates, including carbon steel (CR1018), low alloy steel (4140), stainless steel (SS304) and tungsten carbide, under different water chemistries (i.e., salinity and pH). Measured force profiles revealed that the attractive van der Waals (VDW) interaction contributed to the attachment of the calcium carbonate particles on substrate surfaces, while the repulsive electric double layer (EDL) interactions could inhibit the attachment behaviors. High salinity and acidic pH conditions of aqueous solutions could weaken the EDL repulsion and promote the attachment behavior. The adhesion of calcite particles with CR1018 and 4140 substrates was much stronger than that with SS304 and tungsten carbide substrates. The bulk scaling tests in aqueous solutions from an industrial oil production process showed that much more severe scaling behaviors of calcite was detected on CR1018 and 4140 than those on SS304 and tungsten carbide, which agreed with surface force measurement results. Besides, high salinity and acidic pH can significantly enhance the scaling phenomena. This work provides fundamental insights into the scaling mechanisms of calcite at the nanoscale with practical implications for the selection of suitable anti-scaling materials in petroleum industries.

Study on rust layers of carbon steel, weathering steel and alloy steel exposed to Shanghai atmosphere for three years

The corrosion results of four steels (including carbon steel, weathering steels and alloy steel) exposed to atmospheric environment in Baoshan District of Shanghai for three years were systematically analyzed by means of corrosion weight loss, intelligent digital microscope, scanning electron microscope, energy dispersive spectrometer, confocal microscopy Raman spectrometer, etc. The rust layers on skyward surfaces of corrosion samples were characterized. The results showed that the atmospheric corrosion rate of carbon steel was the highest, and the rust layer exfoliated more. The rust layers of weathering steels and alloy steel exfoliated less, and Cr was enriched in the inner layers, which promoted the formation of compact and protective rust layers, prevented rust exfoliation and oxygen infiltration, contributed to crack restoration, and thus improved atmospheric corrosion resistance.

High-temperature corrosion investigations of deposit containing eutectic KCl-K2SO4 mixture on AISI 1015 and SS304 steels

This study investigated corrosion behaviours of biomass fly ash containing eutectic KCl-K2SO4 mixture on carbon steel AISI 1015 and stainless steel 304 (SS304) at 700 ℃ for 12 h in air. The observed corrosion behaviours were validated by comparing with corrosion on similar materials, including carbon steel STBA 12 boiler tube and SS304 erosion guard, exposed in actual boiler environments. Similar corrosion behaviours were found in both laboratory-scale and field tests. Active oxidation, caused by chlorine, dominated over internal sulfidation for carbon steels. For SS304, presence of chlorine depleted protective oxide layers of SS304, followed by internal sulfidation from sulphur species.

Yielding and buckling behavior of aluminium and steel shear panels with different slenderness ratios

The present study investigates the effects of material mechanical properties and plate slenderness ratios on the nonlinear and cyclic behavior characteristics of metal shear panels (including carbon steel (CS), low yield point steel (LYP160) and aluminium (AL)), using the finite element method. The plates are first qualitatively and quantitatively classified into the five groups of very slender, slender, moderate, stocky and very stocky, regarding their slenderness ratios. Very slender plates have negligible buckling capacity and thus, they buckle at the initial stages of loading. Slender plates buckle in the elastic range of behavior. Moderate plates buckle in the inelastic range of stresses before material yielding occurs in the plates. Stocky plates buckle in the plastic (post-yield) range of stresses. The behavior of very stocky plates is only dominated by yielding phenomenon and they do not buckle during loading. Based on the statistical analysis of results, new relationships for estimation of inelastic and plastic buckling loads are also proposed. The cyclic analysis results show that the energy dissipation capability of very stocky/stocky/moderate plates is solely dependent on the material yield stress and elastic modulus of elasticity, whereas for the slender plates, the effectiveness of material yield stress in the energy dissipation of plates is decreased and the role of the material elastic modulus of elasticity becomes more important. In the case of very slender shear plates, the energy dissipation capability seems to be dependent on the initial and secondary modulus of material only.

Experimental Modeling of Pressure in the Hydrostatic Formation of a Cylindrical Cup with Different Materials

Forming complex sheet products using hydrostatic forming technology is currently a focus of the majority of forming processes. However, in order to increase stability during the forming process, it is necessary to identify and analyze the dependency of the forming pressure and the quality of a product on input parameters. For the purpose of modeling the forming pressure, this paper presents empirical research on the product of a cylindrical cup made of various materials, including carbon steel (DC04), copper (CDA260), and stainless steel (SUS 304) with different thicknesses (0.8 mm, 1.0 mm, and 1.2 mm), under a defined range of binder pressures. The regression method is selected to formulate an equation that shows the relationship between the input parameters, including the materials (ultimate strength and yield stress), workpiece thickness, binder pressure and the output parameter, and the formation of fluid pressure. The mathematical equation allows us to determine the extent of the effect of each input on the forming pressure. The experimental results can be used for the easier planning and forecasting of the process and product quality in hydrostatic forming.

Corrosion Study on Wellbore Materials for the CO2 Injection Process

For reliability and safety issues of injection wells, corrosion resistance of materials used needs to be determined. Herein, representative low-cost materials, including carbon steel X70/1.8977 and low alloyed steel 1.7225, were embedded in mortar to mimic the realistic casing-mortar interface. Two types of cement were investigated: (1) Dyckerhoff Variodur commercial Portland cement, representing a highly acidic resistant cement and (2) Wollastonite, which can react with CO2 and become stable under a CO2 stream due to the carbonation process. Exposure tests were performed under 10 MPa and at 333 K in artificial aquifer fluid for up to 20 weeks, revealing crevice corrosion and uniform corrosion instead of expected pitting corrosion. To clarify the role of cement, simulated pore water was made by dispersing cement powder in aquifer fluid and used as a solution to expose steels. Surface analysis, accompanied by element mapping on exposed specimens and their cross-sections, was carried out to trace the chloride intrusion and corrosion process that followed.

Designing a Chemical Nickel Plating Unit Operating as Part of a Galvanic Line

The paper presents the results of the analysis of the requirements for process equipment for chemical nickel plating of metal products, including carbon steels, titanium, aluminum and their alloys. The disadvantages of standard equipment (UKhN series installations, functioning as a separate process unit) during its operation as part of a galvanic line are listed. The results of the design development of an improved installation for chemical nickel plating of metal products with repeated use of the solution are presented. The testing of the installation under the conditions of a galvanic section of a real mechanical production has shown its high efficiency.

A Study on the Application of Hydraulic Calculations considering the Corrosion Coefficient of Steel Piping for Fire Protection

With the recent enlargement and complication of buildings, damage caused by the incidents of fires breaking out are escalating. Consequently, the use of sprinkler facilities is increasing among water-based fire extinguishing systems. Piping materials used in fire prevention systems include carbon steel (for general or pressure pipeline), CPVC, copper, and stainless-steel. Among these, the steel and CPVC pipes, which are commonly employed in fire prevention, were considered for testing the reliability of the water-based systems. This analysis was performed using the PIPENET software to perform hydraulic calculations in order to examine the flow and pressure at the terminal head when the corrosion coefficient was applied; this coefficient was applied considering the aging of pipes. Assuming a uniform pipe diameter in the steel pipes, the rated flow in the pump installed on the first floor of the basement was reduced by over 10% after 20 years had passed (C value of 90); moreover, the reduction in pressure and flow at its terminal head exceeded 30% and 16.5%, respectively. The results indicate that it is difficult to ensure the reliability of these fire prevention facilities. Furthermore, according to our estimation, considering 30 years had passed (C value of 80), the rated flow of the pump was reduced by over 15%, and the corresponding reduction in pressure and flow at its terminal head exceeded 42% and 24%, respectively.

Machine learning of mechanical properties of steels

The mechanical properties are essential for structural materials. The analyzed 360 data on four mechanical properties of steels, viz. fatigue strength, tensile strength, fracture strength, and hardness, are selected from the NIMS database, including carbon steels, and low-alloy steels. Five machine learning algorithms were applied on the 360 data to predict the mechanical properties and random forest regression illustrates the best performance. The feature selection was conducted by random forest and symbolic regressions, leading to the four most important features of tempering temperature, and alloying elements of carbon, chromium, and molybdenum to the mechanical properties of steels. Besides, mathematic expressions were generated via symbolic regression, and the expressions explicitly predict how each of the four mechanical properties varies quantitatively with the four most important features. The present work demonstrates the great potential of symbolic regression in the discovery of novel advanced materials.

Reactive transport model of lab tests of lime-mortar, compacted bentonite and magnetite geochemical interactions

The geochemical interactions at the interfaces of the materials used for the engineered barrier system (EBS) of spent-fuel and high-level radioactive waste repositories may impact the long-term performance of the EBS. These materials include carbon steel, compacted bentonite and concrete. The geochemical reactions are commonly studied in laboratory and in situ tests and by numerical modelling. Cuevas et al. (2016) performed double interface (2I) lab tests to study the interactions of lime-mortar, bentonite and magnetite on cylindrical cells with an internal diameter of 5 cm and an inner length of 2.5 cm, which were hydrated with a synthetic argillaceous water and heated at 60 °C during 18 months. Here, we present a reactive transport model of the 2I tests of Cuevas et al. (2016). The model confirms the proposed conceptual geochemical model and quantifies the mineralogical alterations and the changes in porosity produced by the complex geochemical interactions of lime-mortar, bentonite and magnetite at 60 °C. The model predicts the dissolution of portlandite in the mortar and the precipitation of calcite, brucite, C1.2SH and C1.6SH in the mortar and the bentonite near the mortar/bentonite interface (MBI). Anhydrite precipitates in the mortar, but it is transformed into gypsum after the cooling of the sample. The model predicts a small precipitation of ettringite. Most of the mineralogical changes are predicted to occur at or near the MBI. The high pH front (pH > 8) penetrates 11 mm into the bentonite at the end of the 2I-3 test. The porosity of the mortar near the MBI increases 1% due to portlandite and gypsum dissolution. On the other hand, the porosity of the bentonite decreases 1% in a 0.2 mm thick band near the MBI due to the precipitation of calcite, brucite, sepiolite and Mg-saponite. Model results reproduce the water content, the saturation degree and the water intake measured at the end of the test and capture the main trends of the mineralogical observations. Model results, however, fail to predict the observed ettringite precipitation in the mortar. The predicted brucite precipitation in the mortar and the bentonite is not confirmed by the experimental data.

Metamaterial sensor application concrete material reinforced with carbon steel fiber

In this paper, a rectangular split ring resonator-type metamaterial (MTM) sensor application is demonstrated in order to examine concrete materials. First, different types of concrete materials including carbon steel fiber with the purity ratio of 0.5%, 1% and 1.5% were prepared by using cement and water and their electrical properties were determined via Nicolson–Ross–Weir tehcnique. After that, compatible MTM-based sensor structure was designed and proposed. In order to find out the effect of the humidity on the concrete material, all samples were kept in the water pool for 28 days, the samples were then taken out and the temperature effect on the concrete materials was observed by increasing the heat up to 30[Formula: see text] and 70[Formula: see text] in the oven. The simulated resonance frequency shifts were observed at 910 MHz for concrete material sensor, 120 MHz for humidity sensor validation and 400 MHz for temperature sensor applications. By having large bandwidth in different fiber contents and validating the physical sensor applications as temperature and humidity, it was shown that the proposed study has novelty in the area of MTM-based sensor applications when it is compared with current state-of-the-art.

An IVTIFN–TOPSIS Based Computational Approach for Pipe Materials Selection

This paper proposes a multicriteria decision-making (MCDM) approach, coupling intervalued trapezoidal intuitionistic fuzzy number (IVTIFN) with the technique for order preference by similarity to ideal solution (TOPSIS) to facilitate the selection of pipe materials. Their integration can maximize the advantage in better expressing decision maker’s preference on the proposed evaluation criteria by using a bounded limit instead of an exact value, to rank material alternatives based upon their functional, economic and environmental attributes. To reduce possible information overlapping resulted from the criteria, Mahalanobis distance is incorporated into IVTIFN–TOPSIS to improve the selection results. An illustrative example is provided to verify the proposed approach and demonstrate its practical application, in which four common alternative materials, including carbon steel, galvanized steel, polyvinyl chloride (PVC) and high-density polyethylenes (HDPE), are subject to precise selection to determine their adaptability in waste-water piping. The selection result indicates that the plastic materials are superior to the metal materials. In particular, HDPE is the optimal material alternative for waste-water collection and transport.

Identification of inclusions in carbon steels using micro‐Raman spectroscopy

As complementary to conventional techniques for inclusion characterization, Raman spectroscopy was applied to the identification of various types of non‐metallic inclusions in carbon steels. The Raman spectroscopic analysis showed that alumina, calcium aluminates, manganese sulfide, and iron sulfide were identified as the major components of non‐metallic inclusions in three low‐carbon steels investigated. Besides the Raman bands, luminescence bands of inclusions were also obtained and verified using different infrared excitation wavelengths. The facile identification of inclusions in carbon steels using Raman spectroscopy has many potential applications in studying corrosion and microstructural properties of steels related to inclusions. Copyright © 2016 John Wiley & Sons, Ltd.

The Use of Barium and Calcium Alloys in the Ladle Furnace Treatment of Selected Grades of Continuously Cast Steels

AbstractThe subject of the paper are the results of laboratory and industrial investigations into the use of Si - Ca - Ba alloys for modifying non-metallic inclusions. Based on laboratory tests, the morphology and chemical composition of non-metallic inclusions in carbon steel were examined before and after refining with the use of the above-mentioned alloy as a refining addition. In particular tests, variable additions of the alloy were used at a constant refining time and temperature.Comparison of the process of casting of a sequence of seven heats of the same steel grade using the stopper system in the tundish was made under industrial conditions. In these heats, additions of Si - Ca (three heats) and Si - Ca - Ba (four heats) were introduced as a non-metallic inclusion modifier in the form of core wires during the process in the ladle furnace. For the investigated heats, the contents of total oxygen and calcium were assayed in the finished steel. A significant effect of the simultaneous addition of barium and calcium on steel castability, and thus on the process of continuous casting of the investigated heats, was found.

Corrosion behaviour of waste disposal container in sub-surface disposal system

This study was conducted in order to clarify the long term corrosion behaviour of containers made of carbon steel. Natural immersion crevice corrosion tests were carried out for 360 days in an alkaline and reducing environment using a combination of materials including carbon steel and welding materials or bolts. In addition, potentiostatic crevice corrosion tests were carried out for 90 days. In both tests, there was no evidence to suggest localised corrosion in the different kinds of metal contact parts, including carbon steel, welding materials and bolts. It was also recognised that crevice corrosion was less likely to be generated on disposal container materials. From these experimental results, it is believed that the possibility of localised corrosion is extremely low if the environment around the carbon steel container is maintained under highly alkaline and reducing conditions.

Hybrid buckling-restrained braced frames

Structural systems that are available in building codes are calibrated for good performance at severe performance objectives (like life safety) under high earthquake hazard levels. However, building performance under low earthquake hazards is uncertain. The optimum seismic structural performance depends directly on the ability of stable hysteretic energy dissipation of ductile systems. This paper introduces a new structural steel system called hybrid buckling-restrained braced frame (BRBF). The “hybrid” term for the BRBF system comes from the use of different steel materials, including carbon steel (A36), high-performance steel (HPS) and low yield point (LYP) steel in the core of the brace. Nonlinear static pushover and nonlinear incremental dynamic analyses were conducted on a variety of BRBF models to compare the seismic behavior of standard and hybrid BRBF systems. Hybrid BRBF systems are shown to have a significant improvement over standard BRBF systems in terms of various damage measures including a significant reduction in the problematic residual displacements of the standard BRBFs.

Larson–Miller Constant of Heat-Resistant Steel

Long-term rupture data for 79 types of heat-resistant steels including carbon steel, low-alloy steel, high-alloy steel, austenitic stainless steel, and superalloy were analyzed, and a constant for the Larson–Miller (LM) parameter was obtained in the current study for each material. The calculated LM constant, C, is approximately 20 for heat-resistant steels and alloys except for high-alloy martensitic steels with high creep resistance, for which \( C \approx 30 \). The apparent activation energy was also calculated, and the LM constant was found to be proportional to the apparent activation energy with a high correlation coefficient, which suggests that the LM constant is a material constant possessing intrinsic physical meaning. The contribution of the entropy change to the LM constant is not small, especially for several martensitic steels with large values of C. Deformation of such martensitic steels should accompany a large entropy change of 10 times the gas constant at least, besides the entropy change due to self-diffusion.

Corrosion of Carbon Steel and Alloys in Concentrated Ammonium Chloride Solutions

Corrosion resistance and the behavior of carbon steel and alloys in high concentration ammonium chloride (NH4Cl) solutions were investigated. This study was conducted to better understand material performance in severe NH4Cl corrosive environments in refineries. Immersion tests were performed under boiling 20 wt% and 40 wt% NH4Cl solutions. Sixteen materials commonly used in refineries and two new alloys were examined, including carbon steel; aluminized carbon steel; aluminum brass; Types 405, 410, 304L, 316L, and 321 stainless steels (UNS S40500, S41000, S30403, S31603, and S32100); 300-series stainless steel with 6% Mo; two types of super duplex stainless steels; Alloys 800, 625, and C-276 (UNS N08800, N06625, and N10276); Grade 2 and Grade 19 titanium (UNS R50400 and R53530); Alloy A (equivalent to a modified Type 317L [UNS S31703] stainless steel); and a modified Alloy 825 (UNS N06845). Significant corrosion was observed in carbon steel in both solutions. The corrosion rates of carbon steel were as high as 25.4 mm/y and 60.4 mm/y in 20 wt% and 40 wt% NH4Cl solutions, respectively. However, neither general corrosion nor pitting was observed on titanium alloys and alloys with a pitting resistant equivalent number (PREN) of 40 and higher. The maximum pit depth had a close relationship with the PREN. In addition, an electrochemical study was used to investigate the corrosion behavior of carbon steel. The effects of the temperature and NH4Cl concentration were determined from polarization curves and the corrosion potential.