A Comparative Study of Acicular Ferrite Transformation Behavior between Surface and Interior in a Low C–Mn Steel by HT-LSCM
Abstract
:1. Introduction
2. Materials and Methods
3. Results and Discussion
3.1. As-Cast Microstructure and Inclusion
3.2. In Situ Transformation Behaviors by LSCM
3.3. Microstructural Comparison between the Surface and Interior
3.4. Micro and Macrohardness
4. Conclusions
- (1)
- Cooling rates have significant influence on the AF transformation behavior. With an increase in cooling rate, the nucleation rate of AF increased and the surface microstructure was more interlocked. Sample surface microstructure formed at 3 °C/s was dominated by ferrite side plates, while the ferrite nucleating sites transferred from grain boundaries to intragranular particles when the cooling rate was 15 °C/s.
- (2)
- The microstructure between the surface and interior of the HT-LSCM sample was obviously different. AF dominating microstructure was always obtained in the sample interior and was much finer than the sample surface. The micro and macrohardness values tested on the sample surface varied significantly, and the microhardness of the sample surface was much lower than that of the sample interior.
- (3)
- The start and finish transformation temperatures of surface layers were both higher than the sample matrix. For the sample surface, the start temperatures of nucleation at grain boundaries and intragranular particles decreased with the increase in cooling rate, where the two nucleation manners happened simultaneously when the cooling rate was 15 °C/s. However, the temperature-dilation curves reflected almost pure intragranular AF transformation behavior.
- (4)
- The combined factors led to the coarse size of AF on the sample surface. AF formed at a higher temperature resulted in a coarse size. The available particles for AF nucleation on the sample surface were quite limited, such that hard impingement between AF plates was much weaker than that in the sample interior. In addition, the transformation stress in austenite on the sample surface could be largely released, which contributed to a coarse AF plate size.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Conflicts of Interest
References
- Shim, J.H.; Cho, Y.; Chung, S.; Shim, J.D.; Lee, D. Nucleation of intragranular ferrite at Ti2O3 particle in low carbon steel. Acta Mater. 1999, 47, 2751–2760. [Google Scholar] [CrossRef]
- Li, X.; Min, Y.; Liu, C.; Jiang, M. Study on the formation of intragranular acicular ferrite in a Zr–Mg–Al deoxidized low carbon steel. Steel Res. Int. 2016, 86, 622–632. [Google Scholar] [CrossRef]
- Yuan, G.; Hu, W.; Wang, X.; Kang, J.; Zhao, J.; Di, H.; Misra, R.D.K.; Wang, G. The relationship between microstructure, crystallographic orientation, and fracture behavior in a high strength ferrous alloy. J. Alloy. Compd. 2017, 695, 526–539. [Google Scholar] [CrossRef]
- Wang, C.; Wang, Z.D.; Wang, G.D. Effect of hot deformation and controlled cooling process on microstructures of Ti–Zr deoxidized low carbon steel. ISIJ Int. 2016, 56, 1800–1807. [Google Scholar] [CrossRef] [Green Version]
- Song, F.Y.; Shi, M.H.; Wang, P.; Zhu, F.X.; Misra, R.D.K. Effect of Mn content on microstructure and mechanical properties of weld metal during high heat input welding processes. J. Mater. Eng. Perform. 2017, 26, 2947–2953. [Google Scholar] [CrossRef]
- Jiang, M.; Wang, X.H.; Hu, Z.Y.; Wang, K.P.; Yang, C.W.; Li, S.R. Microstructure refinement and mechanical properties improvement by developing IAF on inclusions in Ti–Al complex deoxidized HSLA steel. Mater. Charact. 2015, 108, 58–67. [Google Scholar] [CrossRef]
- Kang, Y.; Han, K.; Park, J.H.; Lee, C. Variation in the chemical driving force for intragranular nucleation in the multi-pass weld metal of Ti-containing high-strength low-alloy steel. Metall. Mater. Trans. A. 2015, 46, 3581–3591. [Google Scholar] [CrossRef]
- Loder, D.; Michelic, S.K.; Bernhard, C. Acicular ferrite formation and its influencing factors—A review. J. Mater. Sci. Res. 2017, 6, 24–43. [Google Scholar] [CrossRef] [Green Version]
- Mu, W.; Shibata, H.; Hedström, P.; Jönsson, P.G.; Nakajima, K. Ferrite formation dynamics and microstructure due to inclusion engineering in low-alloy steels by Ti2O3 and TiN addition. Metall. Mater. Trans. B. 2016, 47, 2133–2147. [Google Scholar] [CrossRef]
- Wan, X.L.; Wu, K.M.; Nune, K.C.; Li, Y.; Cheng, L. In situ observation of acicular ferrite formation and grain refinement in simulated heat affected zone of high strength low alloy steel. Sci. Technol. Weld. Joining. 2015, 20, 254–263. [Google Scholar] [CrossRef]
- Mu, W.; Shibata, H.; Hedström, P.; Jönsson, P.G.; Nakajima, K. Combination of in situ microscopy and calorimetry to study austenite decomposition in inclusion engineered steels. Steel Res. Int. 2016, 87, 10–14. [Google Scholar] [CrossRef]
- Hanamura, T.; Shibata, H.; Waseda, Y.; Nakajima, H.; Torizuka, S.; Takanashi, T.; Nagai, K. In-situ observation of intragranular ferrite nucleation at oxide particles. ISIJ Int. 1999, 39, 1188–1193. [Google Scholar] [CrossRef]
- Kikuchi, N.; Nabeshima, S.; Kishimoto, Y.; Matsushita, T.; Sridhar, S. Effect of Ti de-oxidation on solidification and post-solidification microstructure in low carbon high manganese steel. ISIJ Int. 2007, 47, 1255–1264. [Google Scholar] [CrossRef] [Green Version]
- Kikuchi, N.; Nabeshima, S.; Kishimoto, Y.; Nakano, J.; Sridhar, S. Interface Migration Behavior of the δ→γ Interface in Low Carbon High Manganese Steel Samples De-oxidized with Ti or Al. ISIJ Int. 2008, 48, 954–962. [Google Scholar] [CrossRef] [Green Version]
- Kikuchi, N.; Nabeshima, S.; Yamashita, T.; Kishimoto, Y.; Sridhar, S.; Nagasaka, T. Micro-structure refinement in low carbon high manganese steels through Ti-deoxidation, characterization and effect of secondary deoxidation particles. ISIJ Int. 2011, 51, 2019–2028. [Google Scholar] [CrossRef] [Green Version]
- Song, B.; Wen, B. In Situ Observation of the Evolution of Intragranular Acicular Ferrite at Mg-containing Inclusions in 16Mn Steel. J. Manuf. Sci. Prod. 2013, 13, 61–72. [Google Scholar]
- Zhang, D.; Terasali, H.; Komizo, Y. In situ observation of the formation of intragranular acicular ferrite at non-metallic inclusions in C–Mn steel. Acta Mater. 2010, 58, 1369–1378. [Google Scholar] [CrossRef]
- Zhou, B.W.; Li, G.Q.; Wan, X.L.; Li, Y.; Wu, K.M. In-situ observation of grain refinement in the simulated heat-affected zone of high-strength low-alloy steel by Zr-Ti combined deoxidation. Met. Mater. Int. 2016, 22, 267–275. [Google Scholar] [CrossRef]
- Mu, W.; Jönsson, P.G.; Nakajima, K. Recent aspects on the effect of inclusion characteristics on the intragranular ferrite formation in low alloy steels: A review. High Temp. Mater. Process. 2017, 36, 309–325. [Google Scholar] [CrossRef]
- Wang, X.; Wang, C.; Kang, J.; Yuan, G.; Misra, R.D.K.; Wang, G. An in-situ microscopy study on nucleation and growth of acicular ferrite in Ti-Ca-Zr deoxidized low-carbon steel. Mater. Charact. 2020, 165, 110381. [Google Scholar] [CrossRef]
- Zou, X.; Sun, J.; Matsuura, H.; Wang, C. In Situ Observation of the nucleation and growth of ferrite laths in the heat-affected zone of EH36-Mg shipbuilding steel subjected to different heat inputs. Metall. Mater. Trans. B. 2018, 49, 2168–2173. [Google Scholar] [CrossRef]
- Mu, W.; Hedström, P.; Shibata, H.; Jönsson, P.G.; Nakajima, K. High-temperature confocal laser scanning microscopy studies of ferrite formation in inclusion-engineered steels: A review. JOM 2018, 70, 2283–2295. [Google Scholar] [CrossRef] [Green Version]
- Babu, S.S. The mechanism of acicular ferrite in weld deposits. Curr. Opin. Solid State Mater. Sci. 2004, 8, 267–278. [Google Scholar] [CrossRef]
- Sarma, D.S.; Karasev, A.V.; Jönsson, P.G. On the role of non-metallic inclusions in the nucleation of acicular ferrite in steels. ISIJ Int. 2009, 49, 1063–1074. [Google Scholar] [CrossRef] [Green Version]
- Byun, J.S.; Shim, J.H.; Cho, Y.W.; Lee, D.N. Non-metallic inclusion and intragranular nucleation of ferrite in Ti-killed C–Mn steel. Acta Mater. 2003, 51, 1593–1606. [Google Scholar] [CrossRef]
- Seo, K.Y.; Kim, M.; Evans, G.M.; Kim, H.J.; Lee, C. Formation of Mn-depleted zone in Ti-containing weld metals. Weld. World. 2015, 59, 373–380. [Google Scholar] [CrossRef]
- Wang, C.; Wang, X.; Kang, J.; Yuan, G.; Wang, G.D. Effect of thermomechanical treatment on acicular ferrite formation in Ti–Ca deoxidized low carbon steel. Metals. 2019, 9, 296. [Google Scholar] [CrossRef] [Green Version]
- Enomoto, M.; Wu, K.M.; Inagawa, Y.; Murakami, T.; Nanba, S. Three-dimensional observation of ferrite plate in low carbon steel weld. ISIJ Int. 2005, 45, 756–762. [Google Scholar] [CrossRef] [Green Version]
- Miyamoto, G.; Shinyoshi, T.; Yamaguchi, J.; Furuhara, T.; Maki, T.; Uemori, R. Crystallography of intragranular ferrite formed on (MnS + V(C, N)) complex precipitate in austenite. Scr. Mater. 2003, 48, 371–377. [Google Scholar] [CrossRef]
- Kim, Y.M.; Lee, H.; Kim, N.J. Transformation behavior and microstructural characteristics of acicular ferrite in linepipe steels. Mater. Sci. Eng. A. 2008, 478, 361–370. [Google Scholar] [CrossRef]
- Abyzov, A.S.; Fokin, V.M.; Rodrigues, A.M.; Zanotto, E.D.; Schmelzer, J.W.P. The effect of elastic stresses on the thermodynamic barrier for crystal nucleation. J. Non-Cryst. Solids 2016, 432, 325–333. [Google Scholar] [CrossRef]
- Xiong, Z.H.; Liu, S.L.; Wang, X.M.; Shang, C.J.; Misra, R.D.K. Relationship between crystallographic structure of the Ti2O3/MnS complex inclusion and microstructure in the heat-affected zone (HAZ) in steel processed by oxide metallurgy route and impact toughness. Mater. Charact. 2015, 106, 232–239. [Google Scholar] [CrossRef]
C | Si | Mn | Ti | Ca | P | S | Fe |
---|---|---|---|---|---|---|---|
0.08 | 0.25 | 1.56 | 0.01 | 0.001 | 0.011 | 0.007 | Bal. |
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Liu, X.; Yuan, G.; Misra, R.D.K.; Wang, G. A Comparative Study of Acicular Ferrite Transformation Behavior between Surface and Interior in a Low C–Mn Steel by HT-LSCM. Metals 2021, 11, 699. https://doi.org/10.3390/met11050699
Liu X, Yuan G, Misra RDK, Wang G. A Comparative Study of Acicular Ferrite Transformation Behavior between Surface and Interior in a Low C–Mn Steel by HT-LSCM. Metals. 2021; 11(5):699. https://doi.org/10.3390/met11050699
Chicago/Turabian StyleLiu, Xiaojin, Guo Yuan, Raja. Devesh Kumar Misra, and Guodong Wang. 2021. "A Comparative Study of Acicular Ferrite Transformation Behavior between Surface and Interior in a Low C–Mn Steel by HT-LSCM" Metals 11, no. 5: 699. https://doi.org/10.3390/met11050699