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Article

Effects of Vanadium and Niobium on the Mechanical Properties and High-Temperature Oxidation Behavior of Austenitic Stainless Steels

by
Fan Wang
1,2,
Zheng Zhang
1,
Guizhi Xiao
1 and
Dening Zou
1,3,*
1
School of Metallurgy and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
2
Shaanxi Special Equipment Inspection and Testing Institute, Xi’an 710048, China
3
Engineering Research Center on Additive Manufacturing Technology and Application in Universities of Shaanxi Province, Xi’an Siyuan University, Xi’an 710038, China
*
Author to whom correspondence should be addressed.
Metals 2025, 15(4), 347; https://doi.org/10.3390/met15040347
Submission received: 13 February 2025 / Revised: 14 March 2025 / Accepted: 15 March 2025 / Published: 22 March 2025
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Abstract

This study focuses on the effects of vanadium and niobium microalloying elements on the mechanical properties and high-temperature oxidation behavior of austenitic stainless steels. Vanadium–niobium elements were confirmed to play an effective role in fine-grain strengthening at room temperature, achieving a tensile strength and yield strength of approximately 768.8 MPa and 464.6 MPa, respectively, with the additions of 0.32 wt% V and 0.21 wt% Nb. During the high-temperature oxidation process, the weight gain and cracking of the oxide layer increased with increasing niobium–vanadium content. The loose structure and delamination of the oxide layer during the oxidation process were caused by the enhanced internal stress of the oxide layer and the molten state of V2O5 at 850 °C.

1. Introduction

Austenitic stainless steels have been widely used in pipelines of thermal power plants because of their excellent formability and corrosion resistance [1,2,3,4]. As the national energy-saving and emission-reduction strategies continue to be promoted, higher requirements have been put forward for the efficiency of coal utilization and the reduction of pollutant emissions in thermal power plants [5,6,7]. The thermal efficiency of the generator set mainly depends on the steam parameters of the unit, and increasing the steam parameters places greater requirements on the performance of the materials [8,9]. The safety and stability of thermal power plant materials in high-temperature and corrosive environments for long-term service ensure safe operation [5].
Microalloying elements are typically used alone or in combination to control grain size and generate precipitates in steel, resulting in fine-grain strengthening and precipitation strengthening. Wu et al. [10] reported that the addition of Nb to steel hindered grain growth and caused microstructure refinement, whereas the randomly distributed NbC-rich phases promoted precipitation strengthening in steel. Gong et al. [11] noted that carbide and nitride formed from steel grades with two microalloying elements (Ti, Nb) were more stable than those formed from a single element (Nb), accompanied by a stronger pinning effect on grain boundaries. Okayasu et al. [12] revealed that the size of niobium precipitates in austenitic stainless steels regulated precipitation strengthening and grain boundary cohesive strength, which in turn affected the mechanical properties of the material. The solubility of the carbon and nitride formed by V is much greater than that formed by Nb in steel, and it has a stronger affinity for carbon and nitrogen, generating a more stable V(C,N) [13]. Fine-crystalline reinforcement and precipitation strengthening effect are subsequently produced to improve the mechanical properties of the material [14]. Zhang et al. [15] reported that the tensile strength and elongation of Cr19 series duplex stainless steel increased significantly with the addition of V because of the TRIP effect. Liu et al. [16] declared that the synergistic effect of nanoprecipitated phases and fine-grain (FG) organization in V-containing martensitic die steels improved their strength and toughness. Wen et al. [17] demonstrated that the size of the carbide precipitation phase decreased and the strength of the steel increased with increasing V content in Fe-Cr-Ni-Mo high-strength steels. Parker et al. [18] showed that the addition of V to 18Cr9Ni3CuNbN steel preferentially precipitated the fine-sized Z phase, which effectively improved the endurance strength.
Furthermore, some studies investigated the effects of Nb–V microalloying on steel properties. Chen et al. [19] demonstrated that the addition of Nb and V to hot-stamped steel resulted in a decreasing trend in strength with increasing V content. The δ-TRIP steel was microalloyed with Nb–V, which promoted the precipitation of high-density nanoscale Nb–V carbides and increased the tensile strength to 1028 MPa [20]. However, few studies have reported the addition of both Nb and V to austenitic stainless steels. In addition, studies on the high-temperature oxidation properties of austenitic stainless steels with the addition of V and Nb have been mixed. Some results indicate that V forms a precipitated phase that hinders chromium diffusion and reduces oxidation resistance [3]. Nb can effectively form an intermediate layer in the oxide layer to hinder oxidation [21]. Further systematic research is needed on the synergistic effects of Nb and V on the microstructural properties and oxidizing properties of austenitic stainless steels, to reveal the specific strengthening mechanism of V and Nb in austenitic stainless steels and to explore the effects of V and Nb on the oxide film of austenitic stainless steels. This study is based on the addition of certain Nb and V elements to austenitic stainless steel; the influence patterns of Nb and V on the properties of austenitic stainless steel were investigated.

2. Materials and Methods

Two austenitic stainless steels with different chemical compositions were prepared via vacuum induction melting and hot rolled into 6 mm thick plates: 0 V–0 Nb steel and 0.32 V–0.21 Nb steel. The solution treatment was carried out at 1150 °C for 30 min, after which the samples were water quenched. The chemical compositions are listed in Table 1. The chemical composition of 0 V–0 Nb steel is similar to that of 304 N steel.
The mechanical properties were tested according to the National Standard of the P.R.C. GB/T 228.1-2010 standard [22]. The size and shape of the tensile samples are presented in Figure 1. To ensure the consistency of the test results, three parallel samples were taken from each composition in the test process along the longitudinal rolling direction. The microstructure and fracture morphology were determined via a Zeiss Axio Imager A2m metallurgical microscope (OM) (Zeiss, Oberkochen, Germany), a JEOL 700 scanning electron microscope (SEM) (JEOL, Tokyo, Japan), SEM-electron backscatter diffraction (SEM-EBSD), and Rigaku SmartLab SE X-ray diffraction (XRD) (Rigaku, Akishima-shi, Tokyo).
The oxidation test process was carried out in strict accordance with National Standard of the P.R.C. GB/T 13303-1991 [23]. The high-temperature oxidation test was conducted in a BR-14 s-12 box-type resistance furnace via the isothermal oxidation method. The oxidation tests were performed at a temperature of 850 °C for 40, 80, 120, 160, and 200 h. After high-temperature oxidation, the samples were weighed with an electronic balance with an accuracy of 0.1 mg. The samples were placed in the crucible, including weighing the sample before oxidation together with the crucible, and weighing the sample after oxidation together with the crucible. All oxidation products had to be fully retained on the sample and in the crucible when weighing, so the weighing included the spalled oxide scale. The morphology of the oxide film as well as the chemical composition of the test steel were analyzed via a JEOL 700 scanning electron microscope (SEM) (JEOL, Tokyo, Japan) and energy dispersive spectrometer (EDS). In addition, the structural composition of the physical phase of the oxidation products was determined via a D/MAX 2500H Rigaku X-ray diffractometer (Rigaku, Akishima-shi, Tokyo). The chemical valence states of the oxidation products were characterized via an ESCALAB 250× X-ray spectrometer (XPS) (ESCALAB, Belo Horizonte, Brazil).

3. Results and Discussion

3.1. Mechanical Properties

3.1.1. Microstructure

Figure 2 shows the optical microscope (OM) images of different specimens. As can be seen in Figure 2, the microstructure of both specimens is a single austenitic structure. The grain size of the test steel became finer and more uniform with the addition of Nb and V.
To further characterize the microstructure of the specimens, EBSD observations were performed. Figure 3 displays the microstructures of the two test steels, characterized by EBSD inverse pole figure (IPF) maps and associated kernel-averaged misorientation (KAM) maps. The 0 V–0 Nb and 0.32 V–0.21 Nb steels presented fully austenitic microstructures with average grain sizes of ~19.64 ± 12.66 µm and ~7.20 ± 2.63 µm, respectively.
Figure 4 shows the XRD patterns of the two test steels in the solid solution state. The main diffraction peaks that appeared in the test steels were γ austenite (FCC). the positions of these peaks coincide with the standard diffraction peaks of austenitic stainless steels, indicating that a large amount of austenite phase exists in the sample. This is verified by the metallography of the test steels in Figure 2 and the EBSD results in Figure 3.
Austenitic stainless steels generated fine precipitated phases (such as MX and Z phases) during solidification as a result of the addition of Nb and V [24,25,26,27]. MX-type precipitates were composed of M = Nb, V, Cr, and X = C, N, and the fine Z phase was (Cr, Fe)(Nb,V)N [24]. The microstructure in the 0.32 V–0.21 Nb steel was characterized by SEM, as shown in Figure 5. It can be seen that the second phase precipitates in 0.32 V–0.21 Nb steel are distributed at grain boundaries and within the grain. EDS analysis of the precipitated phases was carried out, and the results are shown in Figure 5c–j. It can be analyzed that the precipitated phases in the yellow dashed box in Figure 5b are enriched in the elements of Nb, V, C, and N. Combined with the literature [28], it can be seen that this type of precipitated phases is (Nb,V)(C,N). In contrast, the second phase particles in the red dashed box are brighter than the particles in the yellow box. These types of particles are enriched in the elements Nb, C, and N. Combined with the previous study [29,30], it is known that the precipitation phase is Nb(C,N). These precipitated phases formed by Nb and V played a role in heterogeneous nucleation during both solidification and crystallization processes, thus refining the grains. Moreover, the compounds precipitated at the grain boundaries exhibited a “pinning” effect, inhibiting the migration of the grain boundaries and preventing the growth of the grains.

3.1.2. Tensile Properties

The engineering stress–strain curves of the two samples are shown in Figure 6, and the corresponding tensile property data are summarized in Table 2. The ultimate tensile strength and yield strength of 0 V–0 Nb are approximately 654.6 MPa and 329.5 MPa, respectively. The addition of Nb and V increased the tensile strength to about 768.8 MPa and the yield strength to approximately 464.6 MPa, but the corresponding elongation value decreased from about 96.2% to 55.8%. The addition of Nb and V favored room-temperature tensile strength.

3.1.3. Fracture Analysis

Figure 7 shows the SEM images of the fracture surfaces of the different samples. During the tensile test, the two samples were subjected to tensile stress, resulting in dimples. However, owing to the addition of the microalloying elements V and Nb, the size and depth of the dimples in the two test steels significantly differed. The fracture dimples size was counted using the MIPAR software (MAPAR V5.1.0), and the results are shown in Figure 7c–f. The colors in Figure 7c,d are the dimples marked by the Mipar software when counting dimples. With increasing V and Nb contents, the size and depth of the dimples in the 0.32 V–0.21 Nb steel decreased. Han et al. [31] reported that larger and deeper dimples indicated better plasticity in steel, consistent with the tensile test results. From the fracture SEM results of 0.32 V–0.21 Nb steel, it can be seen that the density of dimples is much higher than that of 0 V–0 Nb steel, and the density of dimples may enable the material to have higher strength because a large number of tough nests can effectively disperse the crack extension when the material is fractured, which improves the strength of the material.
Generally, fine-grain strengthening is described by the Hall–Petch equation (Equation (1) [32,33]:
σ g = k g d − 1 / 2
where k g denotes the Hall–Petch coefficient, and d represents the grain size. To study the contribution of fine-grain strengthening of microalloying elements to the yield strength of test steels, it is necessary to determine the contribution of alloy grain refinement to the yield strength before and after the addition of Nb and V. For the 0 V–0 Nb and 0.32 V–0.21 Nb steels, the results are expressed in Equations (2) and (3), respectively.
σ g 2 = k g d 2 − 1 / 2
σ g 3 = k g d 3 − 1 / 2
The above two equations can be derived from Equation (4):
σ g 3 − σ g 2 = k g d 3 − 1 / 2 − d 2 − 1 / 2
According to previous relevant studies [34], the Hall–Petch coefficient k g of austenitic stainless steel is 395 MPa μm0.5. The yield strengths of 0.32 V–0.21 Nb steel and 0 V–0 Nb steel obtained from tensile tests were approximately 464.6 MPa and 329.5 MPa, respectively. The EBSD results revealed that the grain sizes of the two test steels, d3 and d2, were approximately 19.64 and 7.20 μm, respectively. By substituting the above data into Equation (4), the contribution of fine-grain strengthening was concluded to be approximately 42.9% for the increase in yield strength. Therefore, fine-grain strengthening is an important strengthening mechanism.

3.2. High-Temperature Oxidation Performance

3.2.1. Oxidation Kinetics

Figure 8 shows the oxidation kinetic curves of the test steels at 850 °C for 200 h. The oxidized weight gain of both test steels clearly increased with increasing oxidation time. The 0 V–0 Nb steel possessed a flat weight gain curve at the late stage of oxidation, and the oxidized weight gain of the 0.32 V–0.21 Nb steel was much greater than that of the 0 V–0 Nb steel after 40 h.

3.2.2. Morphology of Oxide Layer

The micromorphology of the samples after oxidation for 120 h was observed via SEM at low magnification (Figure 9), aiming to characterize the integrity of the oxide layer after oxidation of the test steels. Only a very small part of the surface of the 0 V–0 Nb steel underwent cracking and spalling (red marked part in Figure 9a), whereas the oxide layer of the steel containing Nb–V experienced a large scattering and shedding phenomenon (red marked part in Figure 9b). The area where the oxide layer peeled off exposed more substrate surfaces, and the newly exposed area reacted with oxygen, which greatly increased the oxidation rate of the material. According to the oxidation kinetic curve (Figure 8), it can be known that the oxidation weight gain of 0 V–0 Nb steel basically does not increase after 80 h of oxidation, while the oxidation mass gain of 0.32 V–0.21 Nb steel increases with the increase in oxidation time. Therefore, the oxidation product of 0.32 V–0.21 Nb steel is more than 0 V–0 Nb steel.
The surface microstructures of the oxide layers formed by the two test steels after an oxidation time of 200 h are presented in Figure 10. The morphologies of the oxidation products of the two test steels were obviously different. The oxidation products of 0 V–0 Nb steel were fine spinel and lamellar (Figure 10a), whereas the oxidation products of 0.32 V–0.21 Nb steel comprised large lumps of oxidation products covering the surface of the oxidation layer in addition to fine spinel and lamellar layers. The oxidation products of the two test steels were analyzed via EDS, as listed in Table 3. The oxides of 0 V–0 Nb steel mainly consisted of O, Cr, Mn, and Fe; and the oxidation products of 0.32 V–0.21 Nb steel contained O, Cr, Mn, V, and Fe, without obvious enrichment of Nb on the surface of the oxide layer.
The cross-sectional morphology of the oxide layer of the test steel was analyzed via SEM–EDS, as displayed in Figure 11. The yellow dashed lines labeled in (a) and (b) in Figure 11 showed the thickness of the oxide layer for the two test steels. The oxide film of the 0.32 V–0.21 Nb steel was clearly thinner and looser than that of the 0 V–0 Nb steel. The oxide layer on the surface of the tested steels was divided into two sublayers, where the outer part was composed of oxides of Cr, Mn, and Fe, and the layer close to the matrix side was an oxide of Si. In addition, the addition of Nb and V increased the degree of internal oxidation of the material, accompanied by the generation of silicon oxides inside the matrix. The Nb was distributed in the middle of the oxide layer as well as near the surface.

3.2.3. Oxide Phase Analysis

The XRD and XPS results of the test steel surface oxides are shown in Figure 12 and Figure 13, respectively. Cr, Fe, Mn, O, and V were detected on the surface of the 0.32 V–0.21 Nb steel, while higher peak intensities of Cr, Fe, Mn, and O were present on the surface of the oxidized film of the 0 V–0 Nb steel (Figure 13a). There were the electronic orbitals of Cr 2p1/2 and Cr 2p3/2 at 586.6 eV and 576.5 eV in the XPS spectra of 0.32 V–0.21 Nb steel Cr, respectively. The XPS spectra of 0 V–0Nb steel Cr exhibited the electron orbitals of Cr 2p1/2 at 586.2 eV and Cr 2p3/2 at 576.1 eV (Figure 13b). The corresponding Cr was in the +3 valence state, which indicated that chromium oxide was produced in the oxide film. The electron orbital binding energies of Mn 2p1/2 and Mn2 p3/2 of the niobium–vanadium-containing steels were located at approximately 653.1, 652.1 eV and 641.7, 640.4 eV, respectively, suggesting the occurrence of Mn2+ and Mn3+ oxides in the oxide layer. According to the XRD analysis results (Figure 12), Mn3O4 and spinel-structured MnCr2O4 appeared in the oxide film; the XPS spectra of O corresponded to 531.1 eV and 530.3 eV, respectively [35] (Figure 13c). The electron orbital binding energies of Fe 2p1/2 and Fe 2p3/2 were centered at 726.3 and 724.2 eV and 712.9 and 711.1 eV in the 0 V–0 Nb steel, respectively. The peaks of Fe shifted to the right with the addition of niobium and vanadium. The results revealed the presence of Fe2+ and Fe3+ and the XRD results (Figure 12) indicated the presence of Fe3+ and Fe2+ on the surface of the tested steels (Figure 13e) [36]. The niobium was enriched mainly in the interior of the oxide layer during the oxidation process, and no oxides were formed on the surface of the oxide layer, as shown by the SEM morphology of the oxide film cross section (Figure 11). Only V was detected on the surface of the oxide film of the 0.32 V–0.21 Nb steel, forming V2O5.
The PBR value of the oxide (the volume ratio of the oxide to the metal consumed to form the oxide) is an important parameter for evaluating the protective properties of the base metal oxide film. When the PBR value is less than 1, the protective properties of the oxide film are poor in the presence of certain tensile stresses, resulting in incomplete coverage of the metal by the oxide film. Similarly, when the PBR is greater than 3, the oxide film has a weak protective effect due to the compressive stress in the film. The oxide film exhibits a protective effect when the PBR is between 1 and 2. The PBR value of V2O5 was 3.19, which was much larger than that of the main protective oxidation product Cr2O3 (1.99) generated by 0 V–0 Nb steel. In the growth process of V2O5 in the oxide layer, a large internal stress was produced, generating cracking of the oxide film or even a portion of the oxide layer, resulting in an incomplete oxide layer structure. Oxygen atoms can pass through the cracked oxide layer gaps and react with the surface of the material matrix in the high-temperature oxidation process, resulting in a more severe oxidation phenomenon, which is consistent with the surface morphology of the oxide layer [3]. The melting of V2O5 near 670 °C has been reported previously in the related literature [37,38,39,40]. In the high-temperature oxidation process, the melted V2O5 liquid dripped from the sample surface. The melting of the oxide layer exposed the fresh substrate surface, allowing more oxygen to contact the substrate for oxidation to occur, resulting in a thicker oxide layer. V2O5 is an “n-type” oxide, and defects in the n-type oxide, such as interstitial metal ions and oxygen ion vacancies, serve as “fast lanes” for oxygen diffusion [41]. These defects not only provided additional diffusion channels but also reduced the activation energy of oxygen diffusion, thus accelerating the oxygen diffusion process.

4. Conclusions

In this research, the effects of Nb and V elements on the mechanical properties and high-temperature oxidation behavior of austenitic stainless steels were investigated by doping them with V and Nb elements. The main conclusions are summarized as follows:
(1)
The microstructure of the test steel after the addition of V and Nb remained a single-phase austenitic organization. The microalloying elements V and Nb reduced the size of the austenitic grains and refined the grains.
(2)
The V and Nb elements play an effective role in fine-grain strengthening. According to theoretical calculations and experimental results, the contribution of fine-grain strengthening to the room-temperature yield strength was approximately 42.9%.
(3)
The weight gain and oxide film scattering increased significantly with increasing V and Nb contents after the high-temperature oxidation. During high-temperature oxidation, the dissolution of V oxide (V2O5) further increased the stress in the oxide layer and promoted the cracking and peeling of the oxide film.

Author Contributions

Conceptualization, F.W.; Data curation, F.W. and G.X.; Investigation, F.W.; Methodology, F.W. and D.Z.; Writing—original draft, F.W.; Funding acquisition, Z.Z. and D.Z.; Resources, Z.Z. and D.Z.; Formal analysis, F.W. and G.X.; writing—review and editing, Z.Z., G.X. and D.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Major Program of Science and Technology in Shanxi Province (202202050201019), the National Natural Science Foundation of China (52271067), and the Young Science Foundation (52404351).

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.

Acknowledgments

The authors are also very grateful to Jiaojiao Ma, Ning Wang, Bo Song, and Ye Qiang for their contributions to the manuscript in terms of methodology, formal analysis, software, and investigation.

Conflicts of Interest

The authors declare that they have no commercial or associative interests that represent conflicts of interest in connection with this paper submitted.

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Metals 15 00347 g001
Figure 1. Tensile test dimensions.
Figure 1. Tensile test dimensions.
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Figure 2. OM images of test steels of (a) 0 V–0 Nb and (b) 0.32 V–0.21 Nb.
Figure 2. OM images of test steels of (a) 0 V–0 Nb and (b) 0.32 V–0.21 Nb.
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Figure 3. (a,b) Inverse pole figure (IPF) maps, (c,d) kernel average misorientation (KAM) maps, and (e,f) grain size distributions of (a) 0 V–0 Nb steel and (b) 0.32 V–0.21 Nb steel.
Figure 3. (a,b) Inverse pole figure (IPF) maps, (c,d) kernel average misorientation (KAM) maps, and (e,f) grain size distributions of (a) 0 V–0 Nb steel and (b) 0.32 V–0.21 Nb steel.
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Figure 4. XRD diffraction pattern of test steels.
Figure 4. XRD diffraction pattern of test steels.
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Figure 5. SEM morphology and EDS analysis of precipitated phase particles in 0.32 V–0.21 Nb steel: (a,b) SEM images of 0.32 V–0.21 Nb steel; (c–j) EDS maps of precipitated phases in 0.32 V–0.21 Nb steel.
Figure 5. SEM morphology and EDS analysis of precipitated phase particles in 0.32 V–0.21 Nb steel: (a,b) SEM images of 0.32 V–0.21 Nb steel; (c–j) EDS maps of precipitated phases in 0.32 V–0.21 Nb steel.
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Figure 6. Engineering stress–strain curves of test steels.
Figure 6. Engineering stress–strain curves of test steels.
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Figure 7. Fracture surfaces of tensioned specimen: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel, (c) 0 V–0 Nb steel fracture dimple distribution, (d) 0.32 V–0.21 Nb steel fracture dimple distribution, (e) 0 V–0 Nb steel fracture dimple size statistics, (f) 0.32 V–0.21 Nb steel fracture dimple size statistics.
Figure 7. Fracture surfaces of tensioned specimen: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel, (c) 0 V–0 Nb steel fracture dimple distribution, (d) 0.32 V–0.21 Nb steel fracture dimple distribution, (e) 0 V–0 Nb steel fracture dimple size statistics, (f) 0.32 V–0.21 Nb steel fracture dimple size statistics.
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Figure 8. Oxidation kinetics curves of test steels.
Figure 8. Oxidation kinetics curves of test steels.
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Figure 9. SEM morphology of surface oxide film peeling off: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel.
Figure 9. SEM morphology of surface oxide film peeling off: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel.
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Figure 10. SEM morphology of oxide layers for the test steels oxidized at 850 °C for 200 h: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel.
Figure 10. SEM morphology of oxide layers for the test steels oxidized at 850 °C for 200 h: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel.
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Figure 11. Cross-sectional morphology of the experimental steels oxidized at 850 °C for 200 h: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel.
Figure 11. Cross-sectional morphology of the experimental steels oxidized at 850 °C for 200 h: (a) 0 V–0 Nb steel, (b) 0.32 V–0.21 Nb steel.
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Figure 12. XRD patterns of oxidation products.
Figure 12. XRD patterns of oxidation products.
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Figure 13. XPS spectra of the test steels: (a) Full spectrum, (b) Cr 2p, (c) Mn 2p, (d) V 2p, (e) Fe 2p, (f) O 1s.
Figure 13. XPS spectra of the test steels: (a) Full spectrum, (b) Cr 2p, (c) Mn 2p, (d) V 2p, (e) Fe 2p, (f) O 1s.
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Table 1. Chemical composition of steels (wt%).
Table 1. Chemical composition of steels (wt%).
Test SteelsCSiMnCrNiNVNbFe
0 V–0 Nb0.0340.451.1819.088.500.14——Bal
0.32 V–0.21 Nb0.0350.471.1318.858.300.140.320.21Bal
Table 2. The mechanical properties of the steels.
Table 2. The mechanical properties of the steels.
Test SteelsYield Strength (MPa)Tensile Strength (MPa)Elongation (%)
0 V–0 Nb329.5 ± 9.6654.6 ± 7.196.2 ± 5.8
0.32 V–0.21 Nb464.6 ± 17.1768.8 ± 14.055.8 ± 2.9
Table 3. EDS of points (1–3) on the surface oxide corresponding to Figure 10.
Table 3. EDS of points (1–3) on the surface oxide corresponding to Figure 10.
Test SteelsPositionElements (wt%)
OMnCrFeSiVNb
0 V–0 NbP135.782.4954.616.970.15——
P219.5412.4146.565.490.21——
0.32 V–0.21 NbP335.484.1156.542.940.340.340.25
P428.0633.622.783.870.3931.140.14
P534.923.0246.7814.460.130.590.10
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Wang, F.; Zhang, Z.; Xiao, G.; Zou, D. Effects of Vanadium and Niobium on the Mechanical Properties and High-Temperature Oxidation Behavior of Austenitic Stainless Steels. Metals 2025, 15, 347. https://doi.org/10.3390/met15040347

AMA Style

Wang F, Zhang Z, Xiao G, Zou D. Effects of Vanadium and Niobium on the Mechanical Properties and High-Temperature Oxidation Behavior of Austenitic Stainless Steels. Metals. 2025; 15(4):347. https://doi.org/10.3390/met15040347

Chicago/Turabian Style

Wang, Fan, Zheng Zhang, Guizhi Xiao, and Dening Zou. 2025. "Effects of Vanadium and Niobium on the Mechanical Properties and High-Temperature Oxidation Behavior of Austenitic Stainless Steels" Metals 15, no. 4: 347. https://doi.org/10.3390/met15040347

APA Style

Wang, F., Zhang, Z., Xiao, G., & Zou, D. (2025). Effects of Vanadium and Niobium on the Mechanical Properties and High-Temperature Oxidation Behavior of Austenitic Stainless Steels. Metals, 15(4), 347. https://doi.org/10.3390/met15040347

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