Investigating the Effect of Intercritical Annealing Heat Treatment on the Quenching and Partitioning of Ferrite-Bainite-Martensite Microphases in High-Silicon Low-Alloy DIN 1.5025 Steel

Document Type : Research Paper

Authors

• Shima Pashangeh ¹
• Soheil Afkhami ²
• Seyyed Sadegh Ghasemi Banadkouki ³

¹ Assistant prof. of Materials Engineering, Department of Materials Engineering, Yasouj University, Yasouj, Iran

² MSc of Materials Engineering, Department of Mining and Metallurgical Engineering, Yazd University, Yazd, Iran

³ Associate prof., Department of Mining and Metallurgical Engineering, Yazd University, Yazd, Iran

10.30495/jnm.2024.33076.2033

Abstract

Abstract
In this study, the influence of intercritical annealing heat treatment on the quenching and partitioning (Q&P) of ferrite-bainite-martensite multiphase in high-silicon low-alloy DIN 1.5025 steel was investigated. Initially, a normalization heat treatment process involving austenitization at 900°C for 5 minutes followed by air cooling to room temperature was conducted to achieve homogeneous and uniform initial ferritic-pearlitic microstructures for all of the specimens. Subsequently, the Q&P heat treatment cycles comprising partial austenitization in the intercritical austenite-ferrite region at 775°C for 60 minutes, followed by quenching in a molten salt bath of partitioning at temperatures of 250, 300, and 350°C for various durations of 2, 5, 15, 30, and 60 minutes were performed. Optical microscopy (OM) and field-emission scanning electron microscopy (FE-SEM) observations, standard tensile tests, and hardness measurements were employed to evaluate the microstructural changes in relation to the mechanical properties of the specimens. The results demonstrate that the presence of ferrite phase during partial austenitization in the intercritical austenite-ferrite region enriches austenite with carbon, reduces the martensite start temperature (M_s), promotes the formation of fine bainite crystals, and consequently leads to unconventional continuous yield behavior in the specimens. A partitioning heat treatment time of 30 minutes in the molten salt bath at 350°C induces the formation of multiphase microstructures containing a mixture of ferrite-bainite-martensite microphases, along with optimizing the formability and tensile strength properties to values of 16% and 1350 MPa, respectively.

Keywords

• High-silicon low-alloy steel
• intercritical annealing
• quenching and partitioning
• ferrite-bainite-martensite microphases
• superior tensile properties

---

References

1.         Heimbuch R. An overview of the auto/steel partnership and research needs. In: Advanced high-strength steels: fundamental research issues workshop, Arlington, Virginia. 2006.

2.         Maresca F, Polatidis E, Šmíd M, Van Swygenhoven H, Curtin WA. Measurement and prediction of the transformation strain that controls ductility and toughness in advanced steels. Acta Mater. 2020;200:246–55. Available from: https://doi.org/10.1016/j.actamat.2020.08.028

3.         Bouaziz O, Zurob H, Huang M. Driving force and logic of development of advanced high strength steels for automotive applications. steel Res Int. 2013;84(10):937–47.

4.         Christian Lesch Norbert Kwiaton FBK. Advanced High Strength Steels (AHSS) for Automotive Applications − Tailored Properties by Smart Microstructural Adjustments. Steel Res Int. 2017;88(10).

5.         Czerwinski F. Current trends in automotive lightweighting strategies and materials. Materials (Basel). 2021;14(21).

6.         Tsipouridis P. Mechanical properties of dual-phase steels. Technische Universit�t M�nchen; 2006.

7.         Tisza M. Three Generations of Advanced High Strength Steels in the Automotive Industry. In: Jármai K, Voith K, editors. Vehicle and Automotive Engineering 3. Singapore: Springer Singapore; 2021. p. 81–94.

8.         Nayak SS, Anumolu R, Misra RDK, Kim KH, Lee DL. Microstructure – hardness relationship in quenched and partitioned medium-carbon and high-carbon steels containing silicon. 2008;498:442–56.

9.         De Moor E, Speer JG. Bainitic and quenching and partitioning steels. Automotive Steels: Design, Metallurgy, Processing and Applications. Elsevier Ltd; 2016. 289-316 p. Available from: http://dx.doi.org/10.1016/B978-0-08-100638-2.00010-9

10.       Pashangeh S, Banadkouki SSG, Somani MC. Abnormal mechanical response in a silicon bearing medium carbon low alloy steel following quenching and bainitic holding versus quenching and partitioning treatment. J Mater Res Technol. 2020;9(3):5007–23. Available from: https://www.sciencedirect.com/science/article/pii/S2238785419320095

11.       Soleimani M, Kalhor A, Mirzadeh H. Transformation-induced plasticity (TRIP) in advanced steels: A review. Vol. 795, Materials Science and Engineering A. Elsevier B.V.; 2020. 140023 p. Available from: https://doi.org/10.1016/j.msea.2020.140023

12.       Avishan B. Transformation induced plasticity effect under tensile and compression stresses in nanostructured bainite. Mater Sci Eng A. 2018;729:362–9. Available from: https://www.sciencedirect.com/science/article/pii/S0921509318307548

13.       پشنگه ش, کریمی زارچی ح, قاسمی بنادکوکی سص. بررسی رفتار مکانیکی غیرمتعارف فولاد کم‌آلیاژ فنر حاوی %wt Si7/1%wt C- 5/0 در شرایط سه فازی بینیتی- مارتنزیتی-آستنیت باقیمانده. مهندسی متالورژی و مواد. 2020;31(2):137–52. Available from: https://jmme.um.ac.ir/article_33613.html

14.       Franceschi M, Pezzato L, Gennari C, Fabrizi A, Polyakova M, Konstantinov D, et al. Effect of intercritical annealing and austempering on the microstructure and mechanical properties of a high silicon manganese steel. Metals (Basel). 2020;10(11):1–19.

15.       Pashangeh S, Somani M, Sadegh S, Banadkouki G. Structure-Property Correlations of a Medium C Steel Following Quenching and Isothermal Holding above and below the M s Temperature. 2021;61(1):1–10.

16.       Yan S, Liu X, Liu WJ, Liang T, Zhang B, Liu L. Materials Science & Engineering A Comparative study on microstructure and mechanical properties of a C-Mn- Si steel treated by quenching and partitioning ( Q & P ) processes after a full and intercritical austenitization. Mater Sci Eng A. 2017;684(October 2016):261–9. Available from: http://dx.doi.org/10.1016/j.msea.2016.12.026

17.       پشنگه ش, قاسمی بنادکوکی سص. اصلاح شگرف خواص کششی یک فولاد کم‌آلیاژ سیلیسیم متوسط DIN 1.5025 در شرایط عملیات حرارتی کوئنچ و پارتیشن‌بندی تک مرحله‌ای در مقایسه با شرایط کاملا مارتنزیتی. فصلنامه علمی - پژوهشی مواد نوین. 2020;11(40):59–74. Available from: https://jnm.marvdasht.iau.ir/article_4319.html

18.       Kong H, Chao Q, Cai MH, Pavlina EJ, Rolfe B, Hodgson PD, et al. One-step quenching and partitioning treatment of a commercial low silicon boron steel Materials Science & Engineering A One-step quenching and partitioning treatment of a commercial low silicon boron steel. Mater Sci Eng A. 2017;707(December):538–47. Available from: http://dx.doi.org/10.1016/j.msea.2017.09.038

19.       Xia S, Zhang F, Yang Z. Materials Science & Engineering A Microstructure and mechanical properties of 18Mn3Si2CrMo steel subjected to austempering at di ff erent temperatures below M s. Mater Sci Eng A [Internet]. 2018;724(March):103–11. Available from: https://doi.org/10.1016/j.msea.2018.03.067

20.       Speich GR, Szirmae A, Richards MJ. Formation of austenite from ferrite and ferrite-carbide aggregates. TRANS MET SOC AIME. 1969;245(5):1063–74.

21.       Md Arif S, Ghorai S, Nandan Bar H, Mandal D. Effect of quenching and partitioning time on microstructure and mechanical properties of low carbon micro-alloyed steel. Mater Today Proc. 2022;66:3865–9. Available from: https://www.sciencedirect.com/science/article/pii/S2214785322043309

22.       Wang H, Cao L, Li Y, Schneider M, Detemple E, Eggeler G. Effect of cooling rate on the microstructure and mechanical properties of a low-carbon low-alloyed steel. J Mater Sci. 2021;56(18):11098–113. Available from: https://doi.org/10.1007/s10853-021-05974-3

23.       Trzaska J, Jagiełło A St., Dobrzański LA. The calculation of CCT diagrams for engineering steels. Arch Mater Sci Eng. 2009;39:13–20.

24.       Standard Guide for Preparation of Metallographic Specimens. Am Soc Test Mater. 2001;3(July).

25.       Garcia CI, Deardo AJ. Formation of austenite in 1.5 pct Mn steels. Metall Trans A [Internet]. 1981;12(3):521–30. Available from: https://doi.org/10.1007/BF02648551

26.       Speich GR, Demarest VA, Miller RL. Formation of austenite during intercritical annealing of dual-phase steels. Metall Mater Trans A. 1981;12(8):1419–28.

27.       Fonstein N. Advanced high strength sheet steels: physical metallurgy, design, processing, and properties. Springer; 2015.

28.       Ghatei Kalashami A, Kermanpur A, Najafizadeh A, Mazaheri Y. The Effect of Intercritical Annealing Time on the Microstructures and Mechanical Properties of an Ultrafine Grained Dual Phase Steel Containing Niobium. Int J Iron Steel Soc Iran.