Influence of Solution Treatment Duration on Microstructural Features of an Industrial Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

Cojocaru, Vasile; Răducanu, Doina; Angelescu, Mariana Lucia; Vintila, Adrian Nicolae; Şerban, Nicolae; Dan, Ioan; Cojocaru, Elisabeta Mirela; Cincă, Ion

doi:10.1007/s11837-017-2372-0

Cited by 17 publications

(9 citation statements)

References 46 publications

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“…Considering the TM processing specific features, the samples´reference frame, indicated in Figure 2a, assumes the following main directions: RD-rolling direction, TD-transverse direction, and ND-normal direction. The sample's microstructure was analysed in the plane defined The metallographic preparation procedure applied to all the samples collected from all TM processed states is presented and detailed elsewhere [19][20][21]. The microstructure was investigated by SEM techniques, with the purpose of observing the microstructural constituent phases and the changes occurred during TM processing.…”

Section: Methodsmentioning

confidence: 99%

“…All data were rounded to the nearest whole number, in MPa and J (for strength and impact properties), while the elongation was rounded to 0.5% (i.e., according to EN 10002-1). The metallographic preparation procedure applied to all the samples collected from all TM processed states is presented and detailed elsewhere [19][20][21]. The microstructure was investigated by SEM techniques, with the purpose of observing the microstructural constituent phases and the changes occurred during TM processing.…”

Section: Methodsmentioning

confidence: 99%

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Influence of Aging Treatment on Microstructure and Tensile Properties of a Hot Deformed UNS S32750 Super Duplex Stainless Steel (SDSS) Alloy

Cojocaru

Răducanu

Nocivin

et al. 2020

Metals

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In this present study, the influence of isothermal aging temperature and duration on microstructural and mechanical properties of a hot-deformed UNS S32750 super duplex stainless steel (SDSS) alloy was investigated by SEM-EBSD (scanning electron microscopy-electron backscatter diffraction) and tensile testing techniques. An isothermal aging treatment, at temperatures between 400 and 600 °C and treatment duration between 3 and 120 h, was applied to a commercial UNS S32750 SDSS alloy. Microstructural characteristics of all thermomechanical (TM) processed states, such as distribution and morphology of constituent phases, grain’s modal orientation (MO), and obtained mechanical properties were analysed correlated with the TM processing conditions. The obtained experimental results show that the constituent phases, in all TM processed states, are represented by elongated γ-phase grains within the δ-phase matrix. The R-phase was observed in the case of aging treatment performed at 600 °C for 120 h. Within the δ-phase matrix, dynamically recrystallized grains were identified as a result of applying hot deformation and isothermal aging treatments. Also, it was observed that aging treatment parameters can significantly influence the mechanical behaviour exhibited by the UNS S32750 SDSS alloy, in terms of elongation to fracture and absorbed energy during impact testing.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Influence of Aging Treatment on Microstructure and Tensile Properties of a Hot Deformed UNS S32750 Super Duplex Stainless Steel (SDSS) Alloy

Cojocaru

Răducanu

Nocivin

et al. 2020

Metals

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“…Secondary processing, such as heat treating, can also be used to further refine the structure of the steel. In the forging processes of SDSS, a special care is mandatory for the heating and cooling stages, considering the fact that secondary deleterious phases are formed mainly during these periods [19]. For example, it was found that the σ and τ phases are formed due to Cr diffusion towards the grain boundaries during slow cooling after forging [19,20].…”

Section: Introductionmentioning

confidence: 99%

“…In the forging processes of SDSS, a special care is mandatory for the heating and cooling stages, considering the fact that secondary deleterious phases are formed mainly during these periods [19]. For example, it was found that the σ and τ phases are formed due to Cr diffusion towards the grain boundaries during slow cooling after forging [19,20]. It was also shown that σ phase precipitation is a very slow process and small grain sizes and low contents of σ phase are found in the material after soft cooling [21,22], σ phase precipitating mainly in the ferrite-austenite grain boundaries area and around inclusions or incoherent grain boundaries [19,23].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Optimal Forging Temperature Range for an Industrial UNS S32750 SDSS Alloy Using SEM-EBSD Analysis

Angelescu

Cojocaru

Şerban

et al. 2018

Metals

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The deformation temperature of Super-Duplex Stainless Steels (SDSS) is a key factor defining the number of phases, their proportions, and their arrangement in space, with the main role for the hot plastic processing on the industrial scale. The main scope of the study was to determine the optimal forging temperature of UNS S32750 Super-Duplex Stainless Steel by means of the SEM-EBSD technique. The alloy was forged at different temperatures between 800 • C and 1300 • C, after which the most representative samples were analysed by SEM-EBSD. Microstructural characteristics as nature, distribution, morphology, and relative proportion of constituent phases, grain form, homogeneity, and dynamic recrystallization of the structure were analysed in relation to forging temperature. Primary phases as δ-Fe and γ-Fe were identified in all structural states of the steel, irrespective of the deformation temperature. Secondary phases σ-(Cr-Fe) and χ-(Fe-Cr-Mo), identified only under 1050 • C, have a strong negative effect on hot formability because they are fragile. The conclusion was that the optimal forging temperature range for the UNS S32750 steel is 1050-1300 • C because between these temperatures the structure is composed only of ferrite and austenite, without other harmful secondary alloy phases. Due to the dynamic recrystallization, the plasticity of the material also increases in this thermal range.

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“…Currently, studies about heating furnace energy conservation are mainly focused on equipment optimization and reform [1], waste gas heat recycling and utilization [2], development and application of new materials (non-quenched and tempered steel, alloy metals, and so on) [3][4][5], improvement of heat treatment process [6,7], etc. However, the studies about energy-saving scheduling are still limited.…”

Section: Introductionmentioning

confidence: 99%

Research on Energy-Saving Scheduling of a Forging Stock Charging Furnace Based on an Improved SPEA2 Algorithm

Shen

Guan

et al. 2017

Sustainability

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Abstract:In order to help the forging enterprise realize energy conservation and emission reduction, the scheduling problem of furnace heating was improved in this paper. Aiming at the charging problem of continuous heating furnace, a multi-objective furnace charging model with minimum capacity difference and waiting time was established in this paper. An improved strength Pareto evolutionary algorithm 2 (SPEA2) algorithm was designed to solve this problem. The original fitness assignment strategy, crossover operator and population selection mechanism of SPEA2 are replaced with DOPGA (Domination Power of an Individual Genetic Algorithm), adaptive cross operator, and elitist strategy. Finally, the effectiveness and feasibility of the improved SPEA2 was verified by actual arithmetic example. The comparison of results gained from three methods shows the superiority of the improved SPEA2 in solving this problem. Compared with strength Pareto evolutionary algorithm (SPEA) and SPEA2, the improved SPEA2 can get a better solution without increasing time complexity, the heating time is reduced by total 93 min, and can save 7533GJ energy. The research in this paper can help the forging enterprise improve furnace utilization, reduce heating time and unnecessary heating preservation time, as well as achieve sustainable energy savings and emissions reduction.

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Influence of Solution Treatment Duration on Microstructural Features of an Industrial Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

Cited by 17 publications

References 46 publications

Influence of Aging Treatment on Microstructure and Tensile Properties of a Hot Deformed UNS S32750 Super Duplex Stainless Steel (SDSS) Alloy

Influence of Aging Treatment on Microstructure and Tensile Properties of a Hot Deformed UNS S32750 Super Duplex Stainless Steel (SDSS) Alloy

Evaluation of Optimal Forging Temperature Range for an Industrial UNS S32750 SDSS Alloy Using SEM-EBSD Analysis

Research on Energy-Saving Scheduling of a Forging Stock Charging Furnace Based on an Improved SPEA2 Algorithm

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