Carbon Content Of Steel Research Articles

Increasing the the wear resistance of parts made of 110G13L steel

The article analyzes the methods of increasing the wear resistance of parts made of 110G13L steel. On the basis of the conducted experiments, conclusions are given. the maximum impact strength is achieved with a silicon content of up to 0.5%.At the same time, it should be noted that the variation in the chemical composition affects the linear shrinkage of steel, and this is a problem for foundry workers when developing the technology. At one time, OMZ - LP specialists determined the dependence of linear shrinkage of high-manganese steel on changes in its chemical composition on the basis of literature and statistical data. Thus, an increase in the carbon content of steel in the range of 0.9–1.3% reduces the linear shrinkage from 3% to 2.2%. An increase in the silicon content from 0.4 to 1.0% on average leads to a decrease in shrinkage by 0.6%. An increase in the manganese content from 11.5 to 14.5% leads to an increase in linear shrinkage by 0.8%.

Investigation of effect of mechanical properties and Influence of Heat treatment on AISI 4140 steel

The optimization methods in metal heating processes, considered to be a vital tool for continual improvement of output quality in products. In order to optimize the gains from the raw material of AISI 4140 alloy steel, an accurate process must be constructed. The carbon content in AISI4140 steel ranges from 0.38 to 0.43%. In this approach the mechanical properties mainly like Hardness, Yield Strength, Wear Resistance are amenable to modification via heat treatment. In the present work the objective is to test the chosen steel with various heat treatment processes and also analyze their microstructure. A comparative study made across the properties vs. heat treat processes. Finally, to choose the best heat treatment process and optimal properties that can be achieved.

Effect of modes of patenting carbon wire on its properties

To increase the competitiveness of carbon steel grades in enterprises, it is necessary to constantly improve the production process. The manufacture of high-strength wire is an urgent area for the enterprises of the hardware industry. One of the most important indicators determining the quality of the wire is the achievement of the specified physical and mechanical properties and microstructure. To this end, the wire is subjected to patenting, which is carried out in special units. To achieve the desired result during patenting, it is necessary to choose and observe the correct regimes depending on the diameter of the wire being processed and the chemical composition of the steel. When developing the modes, it is taken into account that martensite and a significant amount of excess ferrite along the grain boundaries are not allowed in the structure of patented steel. In the course of the work, an analysis was made of the most common carbon wire patenting modes in production, statistical dependences of the designated heating modes of the wire billet and cooling medium on the parameters of the steel wire, namely, its diameter and carbon content in steel, were obtained. An assessment of its strength properties is also carried out. According to the results of the analysis of patenting modes, it was found that certain difficulties arise when mastering the process of patenting steel wires of thick diameters and a carbon content of more than 0.8. Therefore, the solution of issues related to the course of these processes seems to be an urgent task. The results of the studies show the possibility of ensuring the necessary level of mechanical properties of steel in billets of thick diameters during the implementation of the process using lead melt. The data obtained can serve as a starting point for industrial testing and the prospective development of patenting processes.

A review of end-point carbon prediction for BOF steelmaking process

AbstractThe precise prediction of end-point carbon content in liquid steel plays a critical role in increasing productivity as well as energy efficiency that can be achieved in the basic oxygen furnace (BOF) steelmaking process. Due to numerous and diversity of the studies on BOF end-point carbon prediction, it seems necessary to provide a comprehensive literature review on state-of-the-art developments in end-point carbon prediction for BOF steelmaking. This paper presents the characteristics of different end-point carbon prediction models. The end-point carbon prediction for BOF steelmaking has initially relied on the experience and skill of the operators. With the development of information technology and auto-detection methods, BOF end-point carbon prediction mainly has gone through three stages, such as static prediction, dynamic prediction, and intelligent prediction. Future contributions to the development and application of intelligent end-point carbon prediction in BOF steelmaking are still arduous tasks. However, it is envisaged that the intelligent end-point carbon prediction will witness more frequent applications and greatly improve the high-quality, high-efficiency, and stable production for BOF steelmaking in the future.

Mechanical Properties and Microstructural Aspects of Two High-Manganese Steels with TWIP/TRIP Effects: A Comparative Study

This article is focused on the mechanical behavior and its relationship with the microstructural changes observed in two high-manganese steels presenting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP), namely Steel B and Steel C, respectively. Chemical compositions were similar in manganese, but carbon content of Steel B approximately doubles Steel C, which directly impacted on the stacking fault energy (SFE), microstructure and mechanical response of each alloy. Characterization of as-cast condition by optical microscope revealed a fully austenitic microstructure in Steel B and a mixed microstructure in Steel C consisting of austenite grains and thermal-induced (εt) martensite platelets. Same phases were observed after the thermo-mechanical treatment and tensile tests, corroborated by means of X-Ray Diffraction (XRD), which confirms no phase transformation in Steel B and TRIP effect in Steel C, due to the strain-induced γFCC→εHCP transformation that results in an increase in the ε-martensite volume fraction. Higher values of ultimate tensile strength, yield stress, ductility and impact toughness were obtained for Steel B. Significant microstructural changes were revealed in tensile specimens as a consequence of the operating hardening mechanisms. Scanning Electron Microscopy (SEM) observations on the tensile and impact test specimens showed differences in fracture micro-mechanisms.

Phase determination in dual phase steels via HREBSD-based tetragonality mapping.

Electron Backscatter Diffraction (EBSD) is a widely used approach for characterising the microstructure of various materials. However, it is difficult to accurately distinguish similar (body centred cubic and body centred tetragonal, with small tetragonality) phases in steels using standard EBSD software. One method to tackle the problem of phase distinction is to measure the tetragonality of the phases, which can be done using simulated patterns and cross-correlation techniques to detect distortion away from a perfectly cubic crystal lattice. However, small errors in the determination of microscope geometry (the so-called pattern or projection centre) can cause significant errors in tetragonality measurement and lead to erroneous results. This paper utilises a new approach for accurate pattern centre determination via a strain minimisation routine across a large number of grains in dual phase steels. Tetragonality maps are then produced and used to identify phase and estimate local carbon content. The technique is implemented using both kinetically simulated and dynamically simulated patterns to determine their relative accuracy. Tetragonality maps, and subsequent phase maps, based on dynamically simulated patterns in a point-by-point and grain average comparison are found to consistently produce more precise and accurate results, with close to 90% accuracy for grain phase identification, when compared with an image-quality identification method. The error in tetragonality measurements appears to be of the order of 1%, thus producing a commensurate ∼0.2% error in carbon content estimation. Such an error makes the technique unsuitable for estimation of total carbon content of most commercial steels, which often have carbon levels below 0.1%. However, even in the DP steel for this study (0.1wt.% carbon) it can be used to map carbon in regions with higher accumulation (such as in martensite with nonhomogeneous carbon content). LAY DESCRIPTION: Electron Backscatter Diffraction (EBSD) is a widely used approach for characterising the microstructure of various materials. However, it is difficult to accurately distinguish similar (BCC and BCT) phases in steels using standard EBSD software due to the small difference in crystal structure. One method to tackle the problem of phase distinction is to measure the tetragonality, or apparent 'strain' in the crystal lattice, of the phases. This can be done by comparing experimental EBSD patterns with simulated patterns via cross-correlation techniques, to detect distortion away from a perfectly cubic crystal lattice. However, small errors in the determination of microscope geometry (the so-called pattern or projection centre) can cause significant errors in tetragonality measurement and lead to erroneous results. This paper utilises a new approach for accurate pattern centre determination via a strain minimisation routine across a large number of grains in dual phase steels. Tetragonality maps are then produced and used to identify phase and estimate local carbon content. The technique is implemented using both simple kinetically simulated and more complex dynamically simulated patterns to determine their relative accuracy. Tetragonality maps, and subsequent phase maps, based on dynamically simulated patterns in a point-by-point and grain average comparison are found to consistently produce more precise and accurate results, with close to 90% accuracy for grain phase identification, when compared with an image-quality identification method. The error in tetragonality measurements appears to be of the order of 1%, thus producing a commensurate error in carbon content estimation. Such an error makes an estimate of total carbon content particularly unsuitable for low carbon steels; although maps of local carbon content may still be revealing. Application of the method developed in this paper will lead to better understanding of the complex microstructures of steels, and the potential to design microstructures that deliver higher strength and ductility for common applications, such as vehicle components.

STUDY OF THE INFLUENCE OF THE CARBON CONTENT IN STEEL ON THE STRUCTURE AND MICROHARDNESS OF THE SURFACE LAYER AFTER ELECTROMECHANICAL PROCESSING WITH IMPACT

Experimental data of metallographic and x-ray diffraction studies of the surface layer of various grades of steels subjected to electro-mechanical processing (EMO) with dynamic (shock) application of the deformation force are presented. The influence of the carbon content in steel on the formation of the structure, microhardness and depth of hardening of the surface layer obtained in the field of pulsed temperature-force action is considered.

Study on the prediction of tensile strength and phase transition for ultra-high strength hot stamping steel

The accurate prediction of mechanical properties and phase microstructures is of great significance to the design and development of the ultra-high strength hot stamping steel (UHSHSS). Based on the prediction of JMatPro and the experimental measurement, an accurate modified prediction model of JMatPro for the tensile strength of UHSHSS was proposed in the study, considering the influence of austenitizing temperature. At the same time, the prediction model of phase transition in quenching process of UHSHSS was established. The tensile strength and phase transition models of UHSHSS under different conditions were studied using the prediction models. Results showed that the tensile strength of UHSHSS increased with the increase of C content and decreased with the increase of Si content. For every 0.01 wt% increase in C content, the tensile strength increased by around 30 MPa. For the hot stamping process used in this study, the carbon content of hot stamping steel should be more than 0.35 wt% to achieve 2000 MPa in tensile strength. The volume fraction of the residual austenite in UHSHSS increased with the increase of C and Si content. During the quenching process, the phase transition in UHSHSS was the fastest between 4 s and 8 s, and the average decomposition rate of the austenite reached 17.8% per second. The average volume fraction of residual austenite and martensite in UHSHSS was 3.3% and 96.7%, respectively, when the quenching die temperature was 150 °C. With the increase of the die temperature, the volume fraction of residual austenite in steel increased.

Volatilization Behavior of Manganese from Molten Steel with Different Alloying Methods in Vacuum

The volatilization loss of manganese during the vacuum smelting process is one of the key factors that determines the manufacturing cost and quality of manganese steel. In this study, the laboratory experiments and thermodynamic calculations were performed to investigate volatilization behavior of manganese from molten steels with different alloying methods in vacuum process. Based on the thermodynamic analysis, with the increase of manganese content, the partial vapor pressure of the manganese component increased, resulting in manganese being easily volatilized from molten steel. The carbon content in the steel shows an evident influence on partial vapor pressure of manganese component, and a higher carbon content in steel leads to a lower partial vapor pressure of manganese, but it not influenced by the silicon content. Compared with the alloying method of high carbon ferromanganese, the volatilization loss of manganese in the alloying method of silicon manganese presents faster decay, agreeing well with the thermodynamic analysis. Besides, the volatile fraction generated in the alloying method of high-carbon ferromanganese is composed of a large amount of MnO nanorods with a lateral length approximately 500 nm and a small number of Mn3O4/Mn nanoparticles with a diameter less than 500 nm. Additionally, the volatile fraction generated in the alloying method of silicon manganese shows Mn3O4 nanoparticles as the main phase. It can be inferred that the existence of the manganese oxide phase is attributed to the high chemical activity of nanoscale particles within air.

Melting characteristics of steel scrap with different carbon contents in liquid steel

ABSTRACT The 10 kg induction furnace experiments were carried out to investigate the oxidation and decarburization behaviour and melting characteristics of the steel bars with different carbon contents. In addition, the melting rate of steel bars in the molten bath with different carbon contents and stirring intensity was also studied. Under the same heating conditions, high carbon GCr15 bearing steel is more easily oxidized than 20# steel due to its higher carbon content, while the decarbonization is the opposite. The melting rate of GCr15 bearing steel is greater than that of 20# steel because of its higher carbon content and lower melting point. And the melting rate of steel bar under oxidation condition is slightly higher than that of the non-oxidized steel bar. It was also found that an increase in the carbon content and stirring intensity of the molten metal is beneficial to accelerate the melting of steel bar.

Nanostructured Carbide-Free Bainite Formation in Low Carbon Steel

It is an important challenge to reduce the carbon content in nanostructured bainitic steels for commercialization purposes while still being able to gain the desired microstructural characteristics in nanoscale and not to deteriorate the strength–ductility combinations. That is the point at which an appropriate heat treatment procedure design would be an important parameter. This article aims to investigate how to obtain nanostructured bainite in steel with 0.26 wt% carbon content by applying multi-step austempering procedures. One-, two- and three-step austempering processes have been implemented, and proper heat treatment temperatures and approaches were selected based on dilatometry tests. Results indicated that it has become possible to achieve bainitic ferrites and austenite films with overall thicknesses of 164, 145 and 132 nm and 134, 105 and 90 nm at the end of one-, two- and three-step austempering heat treatments, respectively. Meanwhile, microstructural characteristics resulted in enhanced mechanical properties with ultimate tensile strength (UTS) of 1435, 1455 and 1428 MPa in combination with elongation levels of 15.4, 13.6 and 11.4% after implementing those heat treatments. Finally, it has been shown that applying the multi-step austempering heat treatments resulted in enhanced yield strength and impact toughness values due to the microstructural characteristics and proper heat treatment procedure design.

A Unified Model for Plasticity in Ferritic, Martensitic and Dual-Phase Steels

Unified equations for the relationships among dislocation density, carbon content and grain size in ferritic, martensitic and dual-phase steels are presented. Advanced high-strength steels have been developed to meet targets of improved strength and formability in the automotive industry, where combined properties are achieved by tailoring complex microstructures. Specifically, in dual-phase (DP) steels, martensite with high strength and poor ductility reinforces steel, whereas ferrite with high ductility and low strength maintains steel’s formability. To further optimise DP steel’s performance, detailed understanding is required of how carbon content and initial microstructure affect deformation and damage in multi-phase alloys. Therefore, we derive modified versions of the Kocks–Mecking model describing the evolution of the dislocation density. The coefficient controlling dislocation generation is obtained by estimating the strain increments produced by dislocations pinning at other dislocations, solute atoms and grain boundaries; such increments are obtained by comparing the energy required to form dislocation dipoles, Cottrell atmospheres and pile-ups at grain boundaries, respectively, against the energy required for a dislocation to form and glide. Further analysis is made on how thermal activation affects the efficiency of different obstacles to pin dislocations to obtain the dislocation recovery rate. The results are validated against ferritic, martensitic and dual-phase steels showing good accuracy. The outputs are then employed to suggest optimal carbon and grain size combinations in ferrite and martensite to achieve highest uniform elongation in single- and dual-phase steels. The models are also combined with finite-element simulations to understand the effect of microstructure and composition on plastic localisation at the ferrite/martensite interface to design microstructures in dual-phase steels for improved ductility.

The engineering behind the mechanical properties enhancement on HSLA steels, microalloyed with niobium: Effects of boron and titanium

The influence of boron on the mechanical properties of niobium microalloyed steels was investigated by comparing the variations of rolled strips with and without boron and titanium addition. Chemical analysis, metallography, mechanical properties, hardness and hot-torsion tests were performed to characterize rolled samples with different chemical composition. In order to meet this goal, two different chemical composition for microalloyed steel were designed: Chemical composition A, relative to an ASTM A1018 HSLA (High Strength Low Alloy) grade 50, niobium microalloyed steel, standard, low residuals and target carbon and manganese content of 0.08% and 1.25% respectively. And a chemical composition B, identical to chemical composition A, but with the addition of boron and titanium. One heat of each steel was produced in the BOF (Blast Oxygen Furnace) process, followed by Vacuum Degassing and Slab Continuous Casting. One slab of each heat was rolled into coil, on a Steckel Mill, from which diverse samples were collected at different locations along the length. The characterization tests results presented are for those samples that were rolled under processing conditions closer to the initial planning for both steels. The steel B presents highest values ​​of the yield strength, tensile strength and hardness, lower elongation and larger grain size. This experiment suggests that the boron addition to the HSLA steel, niobium and titanium bearing, allows the achievement of higher yield strength, tensile strength, hardness and lower elongation.

Criteria for achieving the BH effect in ultra-low carbon steels for deep drawing

The authors have investigated key technological parameters of stable production of IF steel sheet with BH-effect. The features of ultralow carbon IF steels and IF steels with BH effect are described. Scheme of IF-BH steel hardening during hot drying of the car body after painting is considered. Data on the chemical composition of IF and IF-BH steels produced at Russian and worldwide enterprises are presented. The authors have analyzed the reasons of appearance of such a defect in the steel sheet as slip bands that arise when the yield area appears on the tensile diagram of steel samples. The requirement on the “shelf life” presented to the IF-BH steel grades is given and disassembled. The article considers the formula for calculating effective carbon content in steel based on the total carbon content in steel, niobium, titanium and nitrogen. The range of carbon effective in steel is given to achieve the optimal value of the BH effect based on previously published works. The results of industrial IF-BH steel production have been analyzed for the conditions of Russian enterprise and recommendations were given on criteria such as the optimum carbon content range in solid solution, the recommended maximum total concentrations of carbon and nitrogen in steel, and the BH effect value guaranteeing a high yield of IF-BH steel sheet in the production. Calculations of various options of microalloying by titanium and niobium for IF-BH steel were done. Criteria are formulated that allow stably obtaining a given value of the BH effect in cold-rolled ultralow-carbon steels. A two-stage scheme for microalloying by titanium and niobium is proposed. The influence of grain size in sheet steel on the presence and value of the BH effect is described as well as on the presence/absence of a yield plateau on the tensile diagram in the sheet metal in the initial state.

Investigation of Nitrogen Containing Austenitic Stainless Steel

An important factor in solving the problem of stainless steel corrosion resistance is carbon concentration reduction. However, a decrease in carbon content of austenitic steels leads to a drop in level of their strength properties. Theoretically, nitrogen alloying can lead to a strength increase in all types of austenitic corrosion-resistant steels. Practically, nitrogen alloying is effectively only with low-carbon compositions. This work shows the effect of nitrogen on the mechanical properties of middle-alloying nitrogen, containing stainless steel, and a study of AISI 304L and pilot steel with different nitrogen content (from 0.16 to 0.30 wt. %). Nitrogen increases strength of steel, which is approximately 30-60% higher than for steel without nitrogen, but reduces technological plasticity. Pilot steels show high corrosion resistance and fine austenite grains.

Microstructure authentication on mechanical property of medium carbon Low alloy duplex steels

The present study emphasizes on the mechanical characterization of medium carbon AISI 1040 and 4140 duplex steels. AISI 1040 and 4140 steels are generally used as structural steels for varying applications, ranging from construction field material to heat resistant parts for moderate temperatures applications. The objective of the present work is to corroborate microstructure and mechanical properties by varying the intercritical temperature in duplex steels. The normalized specimens of as bought steel are heated to a different intercritical temperatures (750, 770, and 790 °C), followed by isothermal holding for 2 h and quenching to room temperature develops duplex phase structure. This treatment grows microstructure with a variable quantity of martensite embedded in a fine ferrite matrix. For the same carbon content in the duplex alloy steels, the addition of Cr, Mo, Si, and Mn, increases the tensile strength and hardness of the material but decreases the toughness and ductility. As the intercritical temperature varies, the amount of martensite and ferrite phases present in the duplex steel also varies, which intern alters the strength and hardness of the material. Duplex steels have higher strength and hardness than as bought, even though the impact strength and ductility are poor. Microhardness is used to identify the micro phases present in the material viz., ferrite and martensite. Microstructure shows the evidence of the formation of a duplex structure with a variation in the amount of aforesaid phases. The result obtained validates the influence of microstructure on mechanical properties of AISI 1040 and 4140 steels.

Criterial Parameters for Achieving the BH Effect in Ultralow-Carbon Steels for Deep Drawing

Key technological parameters of the stable production of interstitial free (IF) grade steel sheet with the bake hardening (BH) effect have been studied. The features of ultralow-carbon IF grade steels and IF steels with the BH effect, as well as the process flowchart for hardening IF-BH steel during hot drying of a car body after painting are described. Data concerning the chemical composition of IF and IF-BH steels produced at Russian and foreign enterprises are presented. The causes of slip band defects in steel sheet occurring when the yield plateau is observed in the tensile diagram of steel samples are analyzed. Requirements for the shelf life of IF-BH steel grades are presented and analyzed. A calculation formula of effective carbon content in steel is proposed based on the content of total carbon, niobium, titanium and nitrogen in steel. The range of effective carbon content in steel required for achieving the optimal BH effect magnitude is presented based on the papers published earlier. The industrial IF-BH steel production results have been analyzed for Russian enterprise conditions. In addition, the following criteria are recommended: the optimum range of carbon content in solid solution, the recommended maximum total concentrations of carbon and nitrogen in steel, and the BH effect magnitude that provides a high yield of IF-BH steel sheet fit for production. The calculations of various IF-BH steel microalloying with titanium and niobium have been performed. Criteria have been formulated that for obtaining a given BH effect magnitude in cold-rolled ultralow-carbon steels. A two-stage scheme for microalloying with titanium and niobium is proposed. The grain size influence in sheet steel upon the presence and BH effect magnitude, as well as upon the presence or absence of a yield plateau observed in the sheet metal’s tensile diagram in the initial state, is described.

Correction to "Determination of Carbon Content in Steels Using Laser-Induced Breakdown Spectroscopy Assisted with Laser-Induced Radical Fluorescence".

Correction to "Determination of Carbon Content in Steels Using Laser-Induced Breakdown Spectroscopy Assisted with Laser-Induced Radical Fluorescence".

Industrial IoT for Intelligent Steelmaking With Converter Mouth Flame Spectrum Information Processed by Deep Learning

In this article, based on the fact that the converter mouth flame is the comprehensive external appearance of the physical and chemical reactions in the converter during the steelmaking process, the continuous spectrum information of the converter mouth flame was obtained by USB4000 spectrometer. In the framework of the Internet of Things, a bidirectional recursive multiscale convolution depth neural network algorithm can take into account the characteristics of frequency domain structure and time domain dynamic sequence. It is applied to the deep-learning of the converter mouth flame spectrum information. The dynamic prediction model of carbon content and temperature value in molten steel at the later stage of steelmaking is constructed. The static control system and dynamic prediction model of automatic steelmaking are intelligently fused to realize one-key steelmaking control. The results show that the average hit rate of carbon content, temperature, and carbon temperature at the end of steelmaking is 94.78%, 98.41%, and 93.43%, which makes the end-point control of steelmaking more stable and the blowing rate less than 1%.

Study on Thickness of Low Carbon Steel in Rapid Cooling Process: A Short Review

For any process that engaged with changes of chemical properties and physical is a heat treatment process by cooling or heating a metal. The technique for heat treatment includes, case hardening, annealing, tempering and precipitation strengthening, quenching and tempering. The mechanical properties like hardness, toughness and ductility can be altered by intense heat treating on steel to produce different mechanical properties. This matters with the carbon content in low carbon steel such as mild steel with above 0.4% carbon, in Medium carbon steel with above 0.8% carbon, and in High Carbon Steel with up to 2% carbon content in steels. To change the characteristics of metals and alloys is by heat treatment process where by altering the diffusion and cooling rate within its microstructure to make them suitable for any kind of usage by changing the grain size at different phases and changing the molecular arrangement.