High Manganese Austenitic Steel Research Articles

Key role of gradient-nanostructure and extremely thin amorphous passive film on tribocorrosion behavior of a novel Cr+N alloyed high-Mn austenitic steel

High manganese steel is influenced by the combined effects of corrosion and wear during service under specific conditions, resulting in components with shortened service life. Under harsh service environments, newly developed Cr+N alloyed austenitic high manganese steel (Mn18Cr7C0.6N0.2 steel) as a new type of railway steel has shown promising results. Herein, the tribocorrosion behaviors of Mn18Cr7C0.6N0.2 and Mn13C1.1 steels in artificial acid rain were studied using electrochemical methods, field emission scanning electron microscope (FE-SEM), focused ion beam scanning electron microscopy (FIB-SEM), scanning transmission electron microscopemicroscopy energy dispersive X-ray spectroscopy (STEM-EDS), and high resolution transmission electron microscopy (HR-TEM). The results showed the formation of passive film and gradient-nanostructure on surfaces of both test steels during tribocorrosion. A dense and tightly adhering amorphous passive film was formed on Mn18Cr7C0.6N0.2 steel surface with a superior blocking effect toward invasive ions. The high strain resistance and plasticity of the Mn18Cr7C0.6N0.2 steel resulted in an intact gradient-nanostructure, suitable for obtaining high surface hardness and maintaining the toughness of the matrix, contribute to providing high wear resistance. The oxide film on the Mn13C1.1 steel surface comprised crystal α-FeOOH. Vortex cracks formed in its gradient structure due to strain localization. Meanwhile, the relatively poor corrosion protection ability and vortex cracks of its gradient-nanostructure prevented it from maintaining interface integrity of the gradient nanostructure, resulting in inferior tribocorrosion resistance. In artificial acid rain, the new type of Cr+N alloyed Mn18Cr7C0.6N0.2 steel exhibited higher tribocorrosion resistance than traditional high manganese steel, promising for use as an excellent wear-resistant material under corrosive environments.

Interaction of erosion and corrosion on high-strength steels used for marine dredging engineering

In this work, the erosion–corrosion performances of three high-strength steel samples: high manganese austenitic steel (HMnS), dual-phase steel (D-PS), and martensitic steel (MS), which are potentially used to construct marine dredged pipelines were investigated in comparison to the Q235 carbon steel. The corrosion-enhanced erosion (C-E) and erosion-enhanced corrosion (E-C) were electrochemically studied in conjunction with surface and subsurface characterizations. Results showed that the fracture of the steel extrusions induced by micro-cutting was the main erosion-corrosion feature under normal sand impacts. The C-E played a significant role in the erosion–corrosion process, which resulted in the dissolution of the work-hardening layer and facilitated the subsurface crack propagation, particularly for D-PS and MS. Although the general E-C rate was low, the concentration of the major anodes at the highly eroded area significantly enhanced the erosion process. Evaluating erosion resistance solely based on hardness is significantly limited. The twinning deformation of the austenite grain in HMnS effectively hindered the crack propagation during the erosion–corrosion. The addition of Al and Cr elements improved the erosion–corrosion resistance of high-strength steels.

Welding Processing of Medium-Manganese Austenitic Steels for Cryogenic Applications

Abstract For several years, the significance of gaseous energy sources (e. g. liquified natural gas and hydrogen) has been increasing worldwide due to environmental and climate policy requirements. Storage and transportation of the liquids occur under cryogenic conditions. This results in specific requirements for the mechanical properties of the materials used at cryogenic temperatures. Nowadays, cold-tough, high-nickel austenites and martensitic steels of type X8Ni9 are used for such purposes. While austenitic materials offer good processing properties, they are not attractive due to their comparatively low strength and high costs. Welding martensitic steel with commonly used nickel-based additives significantly impacts processing quality and process automation due to high magnetic remanence. Additionally, the increased requirements for the storage of liquid hydrogen regarding low-temperature toughness push the conventional low-temperature materials to their limits. A potential solution to the identified challenges can be achieved by using medium- and high-manganese austenitic steels. Within the scope of this work, the medium-manganese steel X2CrMnNiN1775 (1.4371) is investigated as an economical substitute for the conventionally used materials in cryogenic applications. Considering the relevant qualification requirements for welded joints and welding additives, submerged arc welded joints are investigated and their applicability under cryogenic operating temperatures is demonstrated.

An approach to calculating the casting temperature of high-manganese austenite steel

An approach to calculating the casting temperature of high-manganese austenite steel

Developing austenitic high-manganese high-carbon steels for biodegradable stent applications: Microstructural and mechanical studies

Fully degradable stents that temporarily support healing tissue can solve potential long-term complications associated with permanent implants. In this study, we investigate austenitic high-manganese high-carbon steels as promising candidates for such biodegradable stent applications. The microstructural characteristics and mechanical properties of the Fe–Mn–C steels were systematically analysed to assess their suitability for this purpose. A series of four austenitic Fe–Mn–C steels with varying manganese (15 and 30 wt%) and carbon (0.6–1.0 wt%) content were processed by vacuum induction casting, annealing and hot forging. Microstructural analysis was performed, and the hot forged materials were further evaluated using ultrasound, macro hardness, and (stopped) quasi-static tensile tests to assess stent-related parameters. In contrast to the as-cast state, the hot forged steels exhibited high chemical homogeneity, as was found by energy-dispersive X-ray spectroscopy (EDXS). Electron backscatter diffraction (EBSD) revealed comparability between the four steels regarding their annealing twin fractions and grain size distributions. An austenitic microstructure was revealed for all modifications by transmission X-ray diffraction (XRD), except Fe–15Mn–0.6C, which displayed a minor ε–martensite fraction. Reducing manganese from 30 to 15 wt% resulted in favourable effects, including a higher Young's modulus, lowered offset yield strength, and an increased ultimate tensile strength due to larger strain hardening while preserving a high total elongation. However, reducing the carbon content to 0.6 wt% diminished the mechanical performance due to reduced solid solution strengthening and the ε–martensite formation. Among the investigated steels, the novel Fe–15Mn–0.8C alloy exhibited the most attractive combination of the studied properties for potential stent applications.

Determination of rational heat treatment modes for new high-manganese austenitic steel using thermodynamic modeling

Determination of rational heat treatment modes for new high-manganese austenitic steel using thermodynamic modeling

Study on Characteristics of Through-Thickness Crack When Cryogenic Materials are Applied to Independent B Type Tank

Due to climate change, interest in eco-friendly energy is continuously increasing around the world. LNG is an intermediate energy source and its use increases continuously because of its established infrastructure. LNG temperature is -165°C and requires low temperature toughness of tank material. High manganese austenitic steel has similar mechanical properties to cryogenic material for LNG listed in IGC and IGF code. High manganese austenitic steel easily satisfies the low temperature toughness required at cryogenic temperature and shows superior performance in yield strength, tensile strength and elongation, compared to existing materials in IGC and IGF code.</br>In this study, the thickness ratio is reviewed while loading the same LNG fuel. Based on the thickness ratio, the thickness for 9%Ni steel, STS304 and Al5083 is calculated for two standard thickness of 10 mm and 20 mm for the high manganese austenitic steel. 9%Ni steel, STS304, Al5083 and high manganese austenitic steel are compared and reviewed from the viewpoint of the required time for initial surface cracks to grow into through-thickness cracks and the size of through-thickness cracks under the same amount of LNG fuel. The effect of different thickness, welded joint and stress sequence on through-thickness cracks are investigated.

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.

The influence of recrystallization annealing time on high cycle fatigue behavior of high-Mn austenitic steel at 77 K

Three high manganese austenitic steels were prepared by different recrystallization annealing time (0, 32, and 128 min) to investigate the effect of recrystallization annealing time on high-cycle fatigue behavior at 77 K. The microstructure was characterized by means of quasi in situ scanning electron microscope (SEM). When fatigue life is about 5.0 × 106 loading cycles, the fatigue strength at 77 K increases from 512 MPa to 625 MPa with the decrease in recrystallization annealing time (RAT). Decrease in RAT leads to grain refinement and the increase in density of dislocation. Grain refinement can delay crack initiation, prevent crack propagation, and hardly hinders the formation of deformation twins. In addition, it is surprising that the grain refinement and the increase in dislocation density promote the formation of nanoscale voids, which leads to stress relaxation and thus improve the fatigue performance.

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.

Study on the Novel High Manganese Austenitic Steel Welded Joints by Arc Welding for Cryogenic Applications of LNG Tanks

The novel high-Mn austenitic steel is becoming a promising steel for cryogenic applications of LNG tanks. The welded joints take a critical role in cryogenic service for storage tanks. In this work, we developed well-matched high-Mn welding consumables and prepared the welded joints by shielded metal arc welding (SMAW), submerged arc welding (SAW) and gas tungsten arc welding (GTAW). The detailed welding parameters were proposed first, then the welding quality, mechanical properties, and microstructure were investigated. The results show that good welding quality, excellent mechanical properties, and stable levels of mechanical properties were obtained for high-Mn steel welded joints using similar welding consumables, the solid core of electrodes, and solid welding wires. Notably, the lowest cryogenic absorbed energy was found at 5 mm away from the fusion line rather than at the fusion line. The hardness of the welded joints was detected to be less than 280 HV due to the whole austenitic microstructure.

Macroscopic and nanoscale investigation of the enhanced wear properties of medium-Mn steel processed via room-temperature quenching and partitioning

High-manganese austenitic and high hardness martensitic steels are widely used in wear-related applications. However, their abrasive wear performance is unsatisfactory because of the insufficient twinning induced plasticity effect of the former and the weak strain hardening and low crack resistance during wear of the latter. Here, novel wear-resistant steels were developed via alloy design and simple room-temperature quenching and partitioning (RT-Q&P) of medium Mn steels (0.3C–10Mn and 0.3C–10Mn-0.25V). Their microstructure and sliding abrasive wear behavior were compared to those of conventional Hardox400 and Hadfield steels. The two medium-Mn steels had better wear properties than conventional wear-resistant steels. Moreover, the V-containing steel with a multiphase microstructure of tempered martensite, retained austenite, and nano-vanadium carbide precipitates, possessed 2.98 and 3.45 times higher abrasive wear resistance than the Hardox400 and Hadfield steels, respectively. Besides the stimulated transformation-induced-plasticity effect in RT-Q&P steels, the enhanced abrasive wear resistance of V-containing steel was attributed to microstructural refinement and improved strain hardening during wear imparted by V element. The main wear mechanism of RT-Q&P wear-resistant steels was cutting, while it was grooves and pits for Hadfield steel, and peeling pits and delamination for Hardox400 steel. This study can guide the design of structural materials with excellent wear resistance through multiphase microstructural and nano-precipitate regulation to overcome the wear challenges of components.

Synergistic effect of grain size and second-phase particle on the oxidation behaviour of a high-manganese austenitic heat-resistant steel

The effect of grain size and second-phase particles on the oxidation behaviour of a high-manganese austenitic (HMA) heat-resistant steel are investigated. Four HMA steels with controlled grain size and volume fraction of second-phase particles are prepared and then exposed at 1023 K in air for 400 h. The results show that the particle-reinforced HMA heat-resistant steels exhibit excellent oxidation resistance. A physical model was proposed to investigate the synergistic effect of grain size and second-phase particle on the oxide scale evolution in HMA steels. The presence of second-phase particles can significantly reduce the effective grain size for the oxide scale formation by providing diffusion channels. Therefore, the formation of nodular oxide and the occurrence of internal oxidation are effectively inhibited in the particle-reinforced heat-resistant steels.

HOT DUCTILITY BEHAVIOR OF Fe-0.05C-24Mn-3.5Si-1.6Al STEEL WITH Nb AND Ti MICROADDITIONS

"Hot ductility tests were carried out on Fe-0.05C24Mn-3.5Si-1.6Al high-manganese austenitic steel with Nb and Ti microadditions at a concentration of 0.029% and 0.075%, respectively. Hot tensile tests were performed using Gleeble 3800 thermomechanical simulator on specimens with a diameter of 6 mm and 116.5 mm in length. Deformation was carried out in a temperature range from 1050 °C to 1200 °C with a strain rate of 2.5 · 10-3 s -1 and 5.0 · 10-3 s -1 . Hot ductility was determined on the basis on evaluation of reduction in area (RA). Higher values of stress on the work-hardening curves were observed during tension carried out at higher strain rate. An analysis of the form and course of curves obtained in the tensile test allows to state that, in the studied range of hot plastic deformation parameters, the decrease of strain hardening is caused by the process of dynamic recrystallization (DRX). The reduction in area in a temperature range from 1050 °C to 1200 °C decreases from 90% to approx. 58% for the strain rate of 2.5 · 10-3 s -1 and from 82% to 48% – for the strain rate of 5.0 · 10-3 s -1 ."

Susceptibility of High-Manganese Steel to High-Temperature Cracking.

Tests were carried out on two high-Mn steels: 27Mn-4Si-2Al-Nb with Nb microaddition and 24Mn-3Si-1.5Al-Nb-Ti with Nb and Ti microadditions. High-manganese austenitic steels, due to their good strength and plastic properties belong to the AHSS (Advanced High-Strength Steel) group and are used in the automotive industry. The main difficulties faced during the casting of the steel and hot working are hot cracks, which can appear in the surface of the ingot. Cracks on the edges of the sheet after hot rolling are the reason for cutting the edges of the sheet and increasing production costs and material losses. The main reason for the formation of hot cracks is the decrease in metal ductility in the high-temperature brittleness range (HTBR). The width of the HTBR depends on mechanical properties and microstructural factors, i.e., non-metallic inclusions or intermetallic phases at austenite grain boundaries. In this paper, a hot tensile test was performed. The research was performed on the GLEEBLE 3800 thermomechanical simulator. This test allows us to determine the width of the high-temperature brittleness range (HTBR), the Nil Strength Temperature (NST), the Nil Ductility Temperature (NDT), and the Ductility Recovery Temperature (DRT). Hot ductility was determined from the value of the reduction in area R(A). The obtained results make it possible to determine the temperature of the beginning of hot working from the tested high-Mn steels. Fractographic research enabled us to define mechanisms of hot cracking. It was found that hot cracks form as a result of disruptions in the liquid film on crystals' boundaries.

Digital experiment as a method for improving the mechanical properties of Hadfield steel

This study is devoted to determining the optimal composition of high-manganese austenitic Hadfield steel for producing castings with increased impact strength and hardness relative to the standard grade. The chemical composition of the steel was modified in terms of expanding the range of Mn content (12–19 %). The effect of combined doping with a complex of elements Cr, Mo, Ni is considered. Preliminary computer modeling and porosity analysis of the cast billets was carried out to determine the place of cutout of representative samples needed to evaluate the actual chemical composition and mechanical properties. Statistical analysis of the obtained results on the content of elements and impact strength of the samples was performed using the desirability function. Further optimization of the model was carried out using the response surface methodology. Based on the analysis of pairwise interactions, two experimental compositions of the Hadfield steel are proposed. A comparison of grade 110G13L with the proposed compositions based on the level of mechanical properties and grain score by microstructure is given. It is concluded that it is promising to further use the proposed Fe–1.1C–16Mn–0.8Si–1.3Cr–Ni–Mo composition, which can improve the reliability of castings operating under conditions of significant wear.The work was carried out within the framework of the state task for science of the Siberian Federal University, project number FSRZ-2020-0013.

Influence of Carbon Content on Tensile Properties of Pure High Manganese Austenitic Steel

The tensile properties of high manganese austenitic steels with a carbon content ranging from 0.79 to 1.28 wt.% were tested. X-ray diffraction, electron backscattering diffraction, transmission electron microscopy, and optical microscopy were used to observe the microstructures after tensile deformation. Results showed that the strength and plasticity of these high manganese austenitic steels increased with increasing carbon content. The tensile strength and elongation of the 130Mn11 steel reached 941 MPa and 38.2%, respectively. The 0.79% carbon-containing steel (80Mn11) formed the most deformation twins at the same strain because of the low stacking fault energy, which resulted in a high strain hardening rate. However, this high strain hardening rate was unsustainable, and the tensile properties of the 80Mn11 steel were the worst, with its tensile strength nearly 200 MPa lower than that of the 130Mn11 steel. In the case of the 1.28% carbon-containing steel (130Mn11), the relatively low density of deformation twins, the large number of dislocations, and intensified DSA effect made the steel display a moderate strain hardening rate, which facilitated the sustainability of deformation, and an excellent combination of strength and plasticity were obtained.

Heat Treatment of High Manganese Austenitic Steel: Structural and Mechanical Properties

Background: Technological progress is based on the development of different types of materials. Among the materials most solicited, we mention metals and alloys. The development of these materials has been initiated and resulted in a wide range of metallic materials, including austenitic manganese, constituting, until today, a center of interest for various research works given their wide use in the industry as well as the recent progress by observation and characterization instruments. Objective: The aim of the paper is to investigate the heat treatment conditions of high manganese austenitic steel and to determine their influence on the structure and mechanical properties. Methods: The samples were subjected to an austenitization treatment at five different temperatures: 980 °C, 1000 °C, 1020 °C, 1040 °C, and 1060 °C for 1 hour. The experimental techniques used are hardness, nanoindentation tests, optical microscopy and X-ray diffraction. Hardness and microhardness measurements were performed to determine the wear behavior of the studied steels. Result: The results indicated that the temperature affects the microstructure; by increasing the austenitizing temperature with pronounced growth of the austenite as well as the dissolution of carbides M7C3, the nano hardness and the modulus of elasticity decreases considerably. Conclusion: The heat treatment of materials modifying the microstructure is closely related to the mechanical behavior of the austenitic manganese steel. Therefore, the control of structural changes by heat treatment is essential to obtain the desired properties. The established heat treatment conditions of the obtained steel can be suitable for several industrial applications.

Factors Affecting the Mechanical Performance of High Manganese Austenitic Steel

High manganese austenitic steel has attracted increasing attention for its application in liquefied natural gas storage tank materials due to its excellent ductility and low cost. This paper presents an overview of the research progress of high manganese austenitic steel in recent years. As a structural material used at a low temperature environment, high manganese steel should not only have certain strength, but also good toughness to prevent brittle fracture at a low temperature. In this work, factors affecting mechanical properties of high manganese steel are discussed, possible reasons for the deterioration of low-temperature properties are analyzed, and the strengthening and toughening mechanisms of materials are elaborated, which may be beneficial to improve properties of high manganese austenitic steel.