High Manganese Steel Research Articles

Electromagnetic drag forces between HTS magnet and tube infrastructure for hyperloop

Maglevs are typically accelerated using electromagnetic propulsion and levitation. High-temperature superconducting (HTS) magnets along with electrodynamic suspension (EDS) and linear synchronous motors are one of the best options for Hyperloop. However, the strong magnetic fields generated by HTS magnets on the pods inevitably interact with the magnetic and conductive structures in the vacuum tubes, along with the tube itself, while the pods move through the tubes. This interaction is observed as a drag force on the pods, significantly reducing the propulsion efficiency. This study comprehensively analyzes the electromagnetic drag force (EDF) generated by HTS magnets on pods, which accounts for most of the drag forces faced by Hyperloop. Theoretical analysis and 3D FEA simulations are performed to analyze the propulsion forces with HTS magnets and all the drag forces on the pods. The EDF generated by AISI 1010 steel rebars in concrete guideways is even greater than the designed propulsion forces of 40 kN. Consequently, high-manganese (Hi-Mn) steel and insulated steel rebars are adopted and analyzed using 3D FEA simulations. The EDFs generated by the AISI 1010 steel and Hi-Mn steel vacuum tubes are determined by varying the distance between the HTS magnets and tubes at 50 and 1200 km/h, respectively; a minimum distance of 0.75 m is determined by a drag force below 8 kN within their operating velocities. Lastly, the total EDFs of the AISI 1010 steel and Hi-Mn steel tubes with EDS rails are obtained through the optimal design of rebars and tubes. The simulation results show that the total EDFs can be significantly reduced to below 10 kN (approximately 25% of the designed propulsion force after the levitation of pods).

Mechanical Property of New Cast High Manganese Steel and Its Application

Based on the traditional Mn13, the new cast high manganese steel was prepared by adding different Cr, Mo, B, and Re elements in the composition. Its microstructure, mechanical properties, and wear quantity of surface were investigated. Results show that after water toughening, the pearlite dissolved and a few linear carbides were kept at the boundary of grains in the microstructure. All of the hardness was more than 220 HB, impact toughness reached or exceeded 140 J/cm2, and ultimate tensile strength was 753 MPa. The lowest abrasive wear quantity was 0.02 g. The newly cast high manganese steel was applied to produce breaking teeth casting of the crusher. Velocity and temperature fields were simulated to predict some defects during the mold filling and solidification process with finite element software for 4 foundry processes. The optimal technological parameter was adapted to make breaking teeth components.

FRACTURE SAFETY OF LIQUEFIED NATURAL GAS TANK IN CRYOGENIC CONDITIONS

High-manganese austenitic steel has been developed as a new cryogenic steel for application in liquified natural gas (LNG) storage and fuel tanks, with improved fracture toughness and safety at cryogenic temperatures. Generally, the fracture toughness decreases at lower temperatures; therefore, cryogenic steel requires a high fracture toughness to prevent unstable fractures. This study conducted unstable ductile fracture tests with 30-mm-thick high-manganese austenitic steel and evaluated its applicability to LNG storage and fuel tanks. The ductile fracture resistance in the weld joints was evaluated, including the weld metal and heat-affected zone. The unstable fracture resistance was evaluated for different LNG tank types. It was found that high-manganese austenitic steel has excellent unstable fracture characteristics and good material performance as a cryogenic steel; therefore, it can be applied in LNG storage and fuel tanks.

Features and Restrictions of Electroslag Remelting with Silica‐Bearing Slags for Lightweight High Manganese Steel

Experiments are conducted to investigate the electroslag remelting process of Fe‐(20‐30)Mn‐(10‐12.0)Al‐(1‐2)C (wt%) steel in a short collar mold using a characteristic silica‐bearing slag to improve nonmetallic inclusion morphology. The effect of the “one‐slag melt” with silica on the changes in the chemical composition of the ESR ingot along its height is studied. The observed silicon pick‐up in metal at ESR is caused by the interaction of silica‐bearing slag with aluminum from metal composition (10%), stipulated by the ESR process nature and cannot be avoided. CALPHAD prediction of phase formation at observed changes of metal chemistry is proved by microstructure and EDS investigations of as‐cast metal of remelted ingot. Silicon pick‐up in obtained limits does not change the morphology of the main phases in the remelted Fe–Mn–Al–Cr‐C‐(Si) steel, but the microhardness of the phases becomes higher. Due to the low speed of remelting provided by ESR TC, the as‐cast metal structure and nonmetallic inclusions are refined. Experiments show that high silica‐bearing slag is not convenient for remelting high aluminum steels because of silicon transfer into ESR ingot at slag's silica reduction by aluminum.

Tuning mechanical behavior and deformation mechanisms in high-manganese steels via carbon content modification

In this paper, two high-manganese steels with comparable grain sizes and manganese contents, namely 34Mn0.1C and 32Mn0.6C, were investigated to explore the effect of carbon content on the mechanical behavior and deformation mechanisms at both room temperature (RT) and liquid nitrogen temperature (LNT). The results indicate that increasing the carbon content promotes the transition of deformation mechanism from dislocation slip to deformation twinning, which is similar to the effect of reducing the deformation temperature. At RT, the strength and elongation are effectively improved by increasing the carbon content, which is attributed to the transformation of deformation mode. Specifically, the yield strength, the ultimate tensile strength and the total elongation increase from 262 MPa, 595 MPa and 50.4% for the 34Mn0.1C steel to 360 MPa, 846 MPa and 87.4% for the 32Mn0.6C steel, respectively. However, at LNT, the 32Mn0.6C steel exhibites higher strength but lower elongation than the 34Mn0.1C steel. The total elongation decreases from 70.6% to 52.3%, which is because the high carbon content and cryogenic temperature induce the rapid activation of deformation twins, leading to premature fracture.

Microstructure evolution and strain hardening behavior of thermomechanically processed low-C high-manganese steels: an effect of deformation temperature

Effects of reduced (– 40 °C), ambient (20 °C), and elevated (200 °C) deformation temperatures on the microstructure evolution and strain hardening behavior of two low-C thermomechanically processed high-manganese steels were studied. The microstructure was characterized by means of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) techniques. The temperature-dependent tendency of austenite to strain-induced ε/α′-martensitic transformation and mechanical twinning was qualitatively and quantitatively assessed using the EBSD technique. The steel containing 26 wt% of Mn showed the beneficial strength–ductility balance at reduced deformation temperature -40 °C due to the intense Transformation-Induced Plasticity (TRIP) effect which resulted in the formation of significant ε- and α′-martensite fractions during tensile deformation. The mechanical properties of steel containing 27 wt% of Mn were more beneficial at elevated deformation temperature 200 °C due to the occurrence of intense Twinning-Induced Plasticity (TWIP) effect expressed by the presence of significant fraction of mechanical twins. Moreover, at the highest deformation temperature 200 °C, the evidence of thermally activated processes affecting the mechanical behavior of the higher Mn steel was identified and described.

Morphology and formation of three-phase pearlite in an aged 100Mn13 steel

The pearlite formed in 100Mn13 high carbon high manganese steel after 1323 K water toughening subsequently 923 K aging treatment is studied by transmission electron microscope and high-resolution technique. The results show that the pearlite is composed of three phases, which are M3C lamellae, M7C3 lamellae, and ferrite lamellae, respectively, with the orientation relationships of ()α∥()M7C3, ()α∥()M3C, ()M3C∥()M7C3, []M3C∥[]M7C3∥[]α. And M7C3 is formed at the phase interface between M3C and α. The growth physical model of three-phase pearlite is proposed.

The Effects of Post-Welding Heat Treatment on the Cryogenic Absorbed Energy of High Manganese Steel Weld Metal

In this study, a post-weld heat treatment (PWHT) was proposed at high temperatures of 600 °C, 750 °C, and 900 °C for 30 min to significantly improve the impact absorbed energy of high manganese steel weld metal. Electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) were employed to characterize the production and study the deformation mechanisms in the high manganese steel weld metal. The impact absorbed energy is divided into crack initiation energy and crack propagation energy, which are divided by the value of Pmax. The cryogenic impact absorbed energy was 81 J. After PWHT at 600 °C, 750 °C, and 900 °C, it was 75 J, 69 J, and 88 J, respectively. The impact absorbed energies did not follow a proportional relationship with the PWHT temperatures. The increase in impact absorbed energy can be attributed to the narrowing of the dendritic region, which blocks the crack propagation path and efficiently prevents crack propagation. Conversely, the decrease in impact absorbed energy can be attributed to the presence of 100-nm-sized (Cr, Mn)23C6-type carbides at the grain boundaries, which facilitate crack propagation.

Transient evolution of non-metallic inclusions in molten high aluminum and high manganese steel contacting with slag and crucible: experimental investigation and FactSage macros modeling

In this work, high temperature experiments of high Al molten steel contacting with crucible and slag were performed to investigate the effect of crucible–slag–steel reaction on transient evolution of inclusions in the high Al molten steel. Processing samples were taken for the chemical compositions of steel and also the inclusions have been characterized by using SEM and EDS AZtec. FactSage macros have been applied to simulate the evolution of molten steel composition and inclusions in molten steel during steel-slag reaction and comparing to the experimental results. Due to the steel–crucible–slag reactions especially under the condition of the high Al molten steel, the Ca and Mg transferred from slag and crucible to the molten steel and then subsequently led to the evolution of Mg and Ca-containing inclusions. The Mg inclusions transferred from MgAl2O4 to MgO inclusions while Ca transferred to steel and modified MgAl2O4 at crucible interface to form CaMgAl2O5 phase. The FactSage macros modeling did agree reasonably well with the experimental results.

The effect of loading direction and pre-deformation on the low-cycle fatigue behavior of high-manganese twinning-induced plasticity steels

The low-cycle fatigue performance of high-manganese twinning-induced plasticity (TWIP) steels with the specimen axial direction of 0°, 22.5°, 45°, 67.5°, and 90° to the rolling direction is investigated in the range of the total strain amplitudes (Δε/2) of 0.6 % ∼ 4.4 % and two types of pre-deformed conditions (i.e., tension and tension-unloading). Experimental results show that the dependence of the fatigue life on the specimen orientation is obvious for lower strain amplitudes, and it gradually reduces with the increase of the applied strain level. The 0° orientations show the highest sensitivity to the pre-deformation process, and the tension-unloading pre-deformation exhibits the most severe change of the texture at fracture.

Novel Wear-Resistant Mechanism Induced by MUPZs via RRA Process in Microalloyed High Manganese Steel

Microalloying and heat treatment have been regarded as an efficient way to get higher wear resistance in high manganese steel, and multiscale precipitates can be obtained randomly by the aging process; however, most of the previous work on heat treatment was more concerned with peak aging time and not the synergistic mechanism of different sized precipitates. Here, we propose a novel wear-resistant mechanism by multiscale precipitates regulated via a retrogression and re-aging (RRA) process. Micron, submicron, and nano precipitates are obtained by the RRA process and jointly form micro-scale ultrafine precipitation zones (MUPZs), which can protect the matrix surface and reduce the abrasive embedded probability, thus ameliorating the micro-cutting and micro-plowing mechanisms. This novel wear-resistant mechanism induced by MUPZs shows better effect under high impact energy due to sufficient work hardening caused by the interaction between dislocations and multi-scale precipitates in MUPZs. This work was investigated using SEM, EDS, and TEM, combined with mechanical properties and impact abrasive wear tests.

Growing interface structure of pearlite in an aged 100Mn13 steel

Growing interface structure of pearlite in 100Mn13 high carbon high manganese steel was studied after 1323 K solution treatment and subsequently 823 K aging treatment by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The results show that longer pearlite lamellae consisting of ferrite lamella and cementite lamella are formed in initial growth stage of pearlite colony, in which there are protrusions and branches in M3C/γ interface. The cementite lamella is divided along (01¯0) M3C into two parts which differ in some respects, such as edge dislocations, (01¯0) M3C lattice arrangement. Besides, edge interface of ferrite lamella is wavy morphology including two peaks presenting small curvature radius, which accommodate more C atoms under the premise of meeting composition condition for transformation to accelerate the transformation. The growth physical model of cementite lamella with protrusions and branches, ferrite lamella with two peaks and three troughs are respectively proposed.

Microstructure and mechanical behavior of a novel Fe–Mn–C–Cr–Si high-manganese steel

Microstructure and mechanical behavior of a novel Fe–Mn–C–Cr–Si high-manganese steel

Effects of titanium addition on austenite grain size and mechanical properties of high manganese steel

Manganese steels have been widely used in industries due to their good wear resistance, high work hardening ability, and high toughness and ductility. This research investigated the effect of modification, i.e., FeTi and Mischmetal, on the grain size and mechanical properties of the high manganese steel (13–15 wt.%). The alloys are modified at different temperatures of 1500, 1550, and 1600 o. The modified alloys were heat-treated after solidification by a two-step process. The grain size, chemical composition, and phase formation of the heat-treated steel were characterized by Optical Microscopy, X-ray Diffractometry, and Energy-Dispersive X-ray Spectroscopy. The mechanical properties of the steel, such as Brinell hardness, tensile strength, and toughness, were measured. As a result, the grain size of the heat-treated alloys is smaller compared to that of un-modified alloys and decreases with the increase in modification amount. The addition of Ti reduced C in the austenite phase by forming very stable carbides, TiC. Maximum tensile strength of 780 MPa was achieved with the addition of 0.1 wt.% Ti, while maximum fracture toughness was 140 J/cm2 at 0.05 wt.% Ti.

THE EFFECT OF CARBON AND NEGATIVE TEMPERATURE ON THE PHYSICAL, MECHANICAL AND OPERATIONAL PROPERTIES OF AUSTENITIC HIGH-MANGANESE STEEL

Purpose. It consists in determining the influence of carbon and manganese, concentrations of modifiers, test temperatures on the physical and mechanical properties and wear resistance of austenitic highmanganese steel Г13Л.
 Research methods. Determination of impact viscosity was carried out on the MK-30A pendulum probe, microhardness – on the PMT-3 device. The hydrostatic weighing method was used to determine the density. Microstructural analysis and study of non-metallic inclusions were carried out using metallographic and electron microscopes. Corrosion resistance was determined in a model environment with pH9, which corresponded to the production conditions of beneficiation processes of ferrous and non-ferrous metallurgy.
 Results. It was established that the best indicators of the properties of steel 110Г13Л are provided at average values of carbon and manganese concentrations within the standard. For parts that work under low shock loads, it is advisable to use austenitic wear-resistant steels with lower manganese concentrations and higher carbon concentrations within the standard chemical composition.
 Scientific novelty. New dependences on carbon influence, structural modification, non-metallic inclusions, and physical and mechanical properties of high-manganese steel were clarified and obtained. The strength limit of steel increases monotonically with increasing carbon content, and the dependences describing changes in plasticity, impact toughness, and hardness are extreme in nature.
 Practical value. A rational method of modification to improve the operational characteristics of steels is proposed. The influence of the test temperature on the impact toughness of steel with changes in carbon concentrations was studied, as the main indicator of the reliability of machine parts at low temperatures.

Study on the role of cryogenic treatment on corrosion and wear behaviors of high manganese austenitic steel

In this study, electrochemical corrosion and wear experiments were conducted to clarify the role of cryogenic treatment on the microstructural morphology and resistance to corrosion and wear of high-manganese austenitic steel. Heat treatment of the solution (950 °C) and annealing (500 °C and 600 °C) were performed on the hot-rolled specimens. Cryogenic treatment was applied to hot-rolled, hot-rolled + heat treated specimens. Cryogenic treatment is a practical technology for eliminating the strip morphology of hot-rolled specimens and improves the wear resistance of heat-treated specimens. However, it plays different role on the corrosion resistance of tested specimens related with production process. The wear mechanism differs due to the cryogenic treatment. A schematic model of the wear mechanism is proposed based on the experimental results. Cryogenic treatment coarsens the grain size regardless of the production process.

Enhancing hot ductility of a cryogenic high manganese steel at a high strain rate by matrix homogenization

The high temperature brittle zone of cryogenic high manganese (Mn) steel often leads to transverse cracks during hot working process, which seriously hinders the production of its sheets or wires. In the present work, we found that the brittle zone (at temperatures between 800 and 900 °C) can be effectively enhanced by homogenizing the initial microstructure and composition. It was revealed that the elements such as Mn and C tend to be enriched in the inter-dendrite area of the as-cast samples, which is difficult to eliminate even during high temperature forging. The C segregation promotes the formation of fine precipitates, such as NbC and Cr23C6. These carbides are usually located at or near grain boundaries, which can weaken grain boundary cohesion and deteriorate the hot ductility. However, homogenizing the initial composition helps to increase the size of hybrid precipitates containing TiN, WC, MoO2 and WO3 and inhibit the precipitation at grain boundaries. Meanwhile, homogenizing the initial microstructure size and stored energy reduces the critical dynamic recrystallization (DRX) temperature to 850 °C. A lower Z value and critical DRX stress increase the DRX fraction from 24% to 66%, which recover microstructure and inhibit grain boundary slip.

Study on Effects of Ultrasonic Nano-crystal Surface Modification on High-manganese Steels Built by Directed Energy Deposition

Study on Effects of Ultrasonic Nano-crystal Surface Modification on High-manganese Steels Built by Directed Energy Deposition

Erosion-corrosion behaviour of high manganese steel used in slurry pipelines

The regular replacement and maintenance of steel pipes used to transport slurry in oil sands mining and extraction continue to represent a major expense for oil sands operations. Pipeline steels such as API 5 L X65 and X70 are the main materials for the slurry transport system. In our previous work, dual-phase stainless steel showed excellent performance in aeriated (high dissolved oxygen) slurries operated at low to moderate velocities involving erosion-corrosion. However, the benefits of using stainless steel diminish as the oxygen in slurry is depleted or at higher slurry velocities at which mechanical properties, particularly deformation energy or strain-hardening capability, of the steel become more dominant. This article reports our recent studies on erosion-corrosion of high manganese steel at different slurry velocities (3.5 m/s and 5.5 m/s) and different dissolved oxygen levels (0.6 ppm and 3.8 ppm). The erosion-corrosion tests were performed at 60 °C in sand-containing slurry (20% vol. silica) with 500 ppm chloride, which simulated common field situation. Characterization of the steel was carried out with optical and scanning electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction technique, micro-mechanical probe, and electrochemical testing. The performance of the high manganese steel was compared to those of API 5 L pipeline steels commonly used in slurry transport, ASTM A1053 Gr.50 dual-phase ferritic-martensitic stainless steel, and AR400 martensitic hard plate. Results of this investigation demonstrate how the high strain-hardening capability of the high manganese steel produces an outstanding erosion resistance, which is more than two times as high as those of ferritic steels. The results are compared to those obtained through field trials performed in an oil sands coarse tailings pipeline.

Investigation of Structure and Mechanical Characteristics of a High Manganese Steel via SolidCast Simulation Method

Casting is a fabrication method used to create various industrial parts with different shapes. Flaws such as shrinkage, porosity, and short metal filling can result in casting rejection. These flaws are heavily reliant on casting parameter design (gating and riser system design) and can be reduced by optimizing the casting parameter design. The development of materials with new or improved properties has long been the primary objective of materials scientists. The designing of metallic alloys for structural purposes must take strength, toughness, and formability into account to achieve the desired performance. The unique convergence of these essential characteristics that characterize high manganese steels fascinate scientists worldwide. The current work systematically investigated a gating system and riser design effect for high Manganese steel samples (bushes) to develop an understanding of the structure–property relationship. The first conventional manual calculation was performed to design the gating and riser system. Subsequently, a sophisticated simulation software called SolidCast was used to design, validate, and improve the casting parameters of the specimen. To back up the findings, confirmatory experiments were carried out. Both designs were used to make castings in order to check for flaws. The microstructural and mechanical characteristics of these materials were investigated. Visual inspection of the manually-designed castings revealed considerable shrinkage, whereas software-designed castings seemed in good shape, without the shrinkage, macroporosity, and microporosity. The microstructure of the specimens was also studied by applying optical microscopy and SEM analysis. By improving the gating and riser system with the SolidCast software, sound casting was achieved. This improved the quality of casting results with a considerable enhancement of yield strength (~32 percent), hardness (~34 percent), and tensile strength (~27 percent), which may lead to significant cost savings.