Comparison Between Segregation of High‐Manganese Steels from 2‐D Phase‐Field Simulations, 1‐D Analytical Theories, and Solidification Experiments

The segregation patterns of solute elements in the Fe–17.1Mn–0.24C–1.38Al steel are systemically investigated by experiments and simulations. The electron probe microanalyzer (EPMA) is conducted to assess possible micro segregation. The result indicates that with the increase of solid fraction in dendrite arms, Mn shows a positive segregation tendency, C uniformly distributes, and Al content slightly fluctuates. Compared with micro segregation models, experimental results of C match well with the Brody‐Fleming model. The segregation ratios of Mn are in good agreement with the lever‐rule. There is no certain regularity displayed between the experimental and calculation results about the segregation ratios of Al. The matrix of the steel is inhomogeneous with severe Mn and C micro segregation in the inter dendritic zone, whereas Al shows the opposite trend. A multicomponent phase field method coupled to thermodynamic calculations is used to simulate the concentration profiles of solute elements in the dendrite arms, and the numerical results are in favorable agreement with the experimental ones. Finally, the roles of undercooling and cooling rate on dendrite morphology and micro segregation of Mn are investigated. It reveals that large undercoolings could improve Mn segregation, while cooling rates have little effect on the maximum Mn segregation concentration but contribute to reduce the total inter dendritic Mn amount. They both have refinement effects on the dendritic structure. Those are helpful to understand and improve the segregations in Fe–Mn–C–Al steels.

Section: Introductionmentioning

confidence: 99%

Study on Micro Segregation of High Alloy Fe–Mn–C–Al Steel

Shen

Yang

Liu

et al. 2019

“…Performed calculations of the phase composition in the system Fe- (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)Mn-(10-12.0)Al-1-2 C (wt%) indicate that in the considered range of concentrations, the appearance of undesirable phases during hardening is possible. Therefore, for such steels, it is crucial to ensure a stable composition and favorable solidification conditions to obtain a uniform structure: the cooling rate should be high but not cause cracks in the surface area.…”

Section: Discussionmentioning

confidence: 99%

“…On the contrary, a limited number of publications are devoted to the melting and refining of high‐manganese steels to remove harmful admixtures, [ 20,21 ] as well as research focused on casting and solidification. [ 22,23 ] Furthermore, there is a scarcity of studies examining the effect of slag on the final composition of these steels. [ 24 ]…”

Section: Introductionmentioning

confidence: 99%

“…On the contrary, a limited number of publications are devoted to the melting and refining of high-manganese steels to remove harmful admixtures, [20,21] as well as research focused on casting and solidification. [22,23] Furthermore, there is a scarcity of studies examining the effect of slag on the final composition of these steels. [24] Electroslag remelting (ESR) is a benchmark process for manufacturing high-quality, low-segregation ingots, especially for big cross-section components, from sophisticated steels and alloys that are used in the most critical applications, such as nuclear, petrochemical, mining, and other key branches of modern industry.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Medovar

Stovpchenko

Lisova

et al. 2023

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.

“…Micro-segregation in high Mn steels can have a significant effect on the mechanical properties at ambient temperature. [17][18][19] Compared to fundamental aspects and the properties under application conditions, the behavior of high and medium Mn steels during production and processing has not found so much attention. The behavior during cold rolling has been investigated by Ofei et al [20] The strain rate effect on the mechanical properties is important to adjust forming processes to the specific material and it is furthermore important for the crash performance in automotive applications.…”

mentioning

confidence: 99%

High‐Temperature Properties of High Mn Steel with Al, Si, and C

Wang¹,

Spitzer

2022

In the automotive industry, greenhouse gas emission reduction and improvement of vehicle safety are the main goals. New materials are considered to contribute significantly to this aim. [1] In this respect steels combining both high strength and high ductility offer considerable benefits. Due to high strength, the sheet thickness can be reduced without loss of stability, thereby, a weight reduction is achieved. High ductility enlarges the degrees of freedom in the design of components. Furthermore, it yields high energy absorbing ability in a crash. A unique combination of high strength and ductility is provided by high manganese steel.The properties of high manganese steels result from different mechanisms, such as crystallographic slip, the transformation of metastable austenite to martensite (TRIP), [2] twinning (TWIP), [3,4] and nano size κ-carbide formation (TRIPLEX). [5] High Mn steel containing about 13 wt.-% Mn and up to 1.4 wt.-% C, first made by Sir Robert Abbott Hadfield in the 1880s, is famous for its high impact strength and resistance to abrasion. [6] By variation of the Mncontent from 5 to 30 wt.-% (medium to high Mn steels) and by alloying with Al, Si, and C the excellent mechanical properties of Mn steel can be further optimized and adjusted. The addition of Al and Si improves roomtemperature properties by adjusting stacking fault energy and it also reduces density. [5,7,8] Increasing C-content in a suitable range was found to increase both strength and ductility. [9] Microalloying with Ti, Nb, and V can be used to increase yield strength by precipitation hardening. [10] Thermomechanical treatment, e.g., by warm rolling at about 200 °C and subsequent annealing at 520-550 °C, adjusts deformation mechanisms and in this way the resulting properties. [11] Furthermore, properties can be adjusted by annealing, e.g., to control the carbide morphology. [12] Apart from the mechanical properties, various further aspects of high Mn steel properties have been investigated like crack formation mechanisms and the influence of hydrogen. [13][14][15][16] Hydrogen embrittlement and delayed fracture is a serious problem for certain highmanganese steels. Micro-segregation in high Mn steels can have a significant effect on the mechanical properties at ambient temperature. [17][18][19] Compared to fundamental aspects and the properties under application conditions, the behavior of high and medium Mn steels during production and processing has not found so much attention. The behavior during cold rolling has been investigated by Ofei et al. [20] The strain rate effect on the mechanical properties is important to adjust forming processes to the specific material and it is furthermore important for the crash performance in automotive applications. [21] For casting, [22][23][24][25][26] hot rolling, [27] and welding, [28,29] the hightemperature properties are of crucial importance and it is essential to ensure a sufficient quality in these process steps. High-temperature brittleness restricts the applicability of the con...