AUSTENITE TRANSFORMING IN CONTINUOUS COOLING PROCESS UNDER DIFFUSION CONTROL MODEL

doi:10.11900/0412.1961.2015.00305

Acta Metall Sin

2015, Vol. 51

Issue (11): 1341-1348 DOI: 10.11900/0412.1961.2015.00305

Current Issue | Archive | Adv Search

AUSTENITE TRANSFORMING IN CONTINUOUS COOLING PROCESS UNDER DIFFUSION CONTROL MODEL

Lei WANG,Di TANG(

),Yong SONG

Engineeing Research Institute, University of Science and Technology Beijing, Beijing 100083

Cite this article:

Lei WANG,Di TANG,Yong SONG. AUSTENITE TRANSFORMING IN CONTINUOUS COOLING PROCESS UNDER DIFFUSION CONTROL MODEL. Acta Metall Sin, 2015, 51(11): 1341-1348.

Download:

HTML

PDF(883KB)
Export: BibTeX | EndNote (RIS)

Abstract

Austenite-ferrite transformation in low carbon steels has a fundamental role in phase transformation and is industrial importance. The kinetics of austenite transformation can be described by the kinetics of austenite-ferrite interface migration. Two classical models, the diffusion-controlled growth model and the interface-controlled model, can be used to describe the growth of proeutectoid ferrite during g→a isothermal transformation. The austenite transformation in continuous cooling process is more common in production. In continuous cooling process, the equilibrium carbon concentrations in austenite and ferrite change with temperature and the kinetics of austenite transformation is different from that in isothermal process. Based on the models for g→a isothermal transformation, a diffusion control model is established for the growth of proeutectoid ferrite during the decomposition of supersaturated austenite in continuous cooling process. The interface position of proeutectoid ferrite varying with temperature is described with the model. The soft impingement effect at the later stage of transformation is considered. The carbon concentration at the austenite side of interface is difficult to reach the equilibrium carbon concentration when the cooling rate is high. A parameter as the function of cooling rate is proposed to modify the carbon concentration at the austenite side of interface. The polynomial diffusion field approximation is assumed in front of the interface. Simulation is done by utilizing the model to analyze the growth of proeutectoid ferrite in continuous cooling process with different bulk concentrations, austenite grain sizes and cooling rates. The interface position of proeutectoid ferrite as a function of temperature or time is obtained under different cooling conditions. Also, carbon diffusion length at the austenite side of interface as a function of time and carbon profile as a function of interface position are obtained under different cooling conditions. Furthermore, the proeutectoid ferrite fraction as a function of temperature can be acquired. The change law of carbon diffusion length with interface position and the change law of interface position with square root of time are discussed. The simulation results of diffusion control for austenite transforming in Fe-0.17C (mass fraction, %) alloy with grain size of 17 mm and different cooling rates show a good agreement with the literature results previously reported.

Key words: diffusion control austenite continuous cooling proeutectoid ferrite interface position

Fund: Supported by Fundamental Research Funds for the Central Universities (No.FRF-IC-14-005)

	Service

	E-mail this article
	Add to citation manager
	E-mail Alert
	RSS
	（）
	Articles by authors
	Lei WANG
	Di TANG
	Yong SONG

URL:

https://www.ams.org.cn/EN/10.11900/0412.1961.2015.00305 OR https://www.ams.org.cn/EN/Y2015/V51/I11/1341

Fig.1 Schematic of the diffusion fields evolution during austenite transforming in continuous cooling process for the diffusion-controlled growth model (x₀ is the position of austenite/ferrite interface, L is the length of diffusion field, C^g and C^a are the equilibrium carbon concentrations in austenite and ferrite, C₀ is the bulk carbon concentration, C_m is the carbon concentration at the center of austenite, X is the centre of austenite, T₁~T₇ are temperatures)

Fig.2 Comparison between calculation results and literature results^[24] at different cooling rates

Fig.3 Interface position as a function of temperature (d—austenite grain size, j—cooling rate)

(a) d=15 mm, j=1 ℃/s (b) d=15 mm, j=5 ℃/s (c) d=30 mm, j=1 ℃/s (d) d=30 mm, j=5 ℃/s

Fig.4 Diffusion length and solute concentration at the center of the austenite phase as a function of temperature in Fe-0.3C alloy with austenite grain size of 30 mm and cooling rate of 1 ℃/s

Fig.5 Carbon profile evolution in the austenite phase in Fe-0.3C alloy with austenite grain size of 15 mm under j=1 ℃/s (a) and j=5 ℃/s (b)

Fig.6 Interface position and diffusion length as a function of time

(a) d=15 mm, j=1 ℃/s (b) d=15 mm, j=5 ℃/s (c) d=30 mm, j=1 ℃/s (d) d=30 mm, j=5 ℃/s

Fig.7 Interface position as a function of temperature in Fe-0.3C alloy with austenite grain size of 15 mm and cooling rates of 1 and 5 ℃/s

Fig.8 Interface position and diffusion length as a function of time in Fe-0.3C alloy under j=1 ℃/s (a) and j=5 ℃/s (b)

Fig.9 Diffusion length as a function of the interface position in Fe-0.1C, Fe-0.3C and Fe-0.5C alloys with austenite grain size of 30 μm under j=1 ℃/s (a) and j=5 ℃/s (b)

Fig.10 Interface position as a function of t^1/2 in Fe-0.1C, Fe-0.3C and Fe-0.5C alloys with different austenite grain sizes and cooling rates

(a) d=15 mm, j=1 ℃/s (b) d=15 mm, j=5 ℃/s (c) d=30 mm, j=1 ℃/s (d) d=30 mm, j=5 ℃/s

[1]	Liu Z Y, Yang Z G, Li Z D, Liu Z Q, Zhang C. Acta Metall Sin, 2010; 46: 390 (刘志远, 杨志刚, 李昭东, 刘振清, 张弛. 金属学报, 2010; 46: 390)
[2]	Svoboda J, Fischer F, Fratzl P, Gamsjager E, Simha N K. Acta Mater, 2001; 49: 1249
[3]	Bos C, Sietsma J. Scr Mater, 2007; 57: 1085
[4]	Capdevila C, Caballero F, de Andres C G. Metall Mater Trans, 2001; 32A: 661
[5]	Chen H, van der Zwaag S. J Mater Sci, 2011; 46: 1328
[6]	Fazeli F, Militzer M. Metall Trans, 2005; 36A: 1395
[7]	Gamsjager E, Militzer M, Fazeli F, Svoboda J, Fischer F D. Compu Mater Sci, 2006; 37: 94
[8]	Purdy G, ?gren J, Borgenstam A, Brechet Y, Enomoto M, Furuhara T, Gamsjager E, Gouné M, Hillert M, Hutchinson C, Militzer M, Zurob H. Metall Mater Trans, 2011; 42A: 3703
[9]	Bhadeshia H K D H. Prog Mater Sci, 1985; 29: 321
[10]	van der Ven A, Delaey L. Prog Mater Sci, 1996; 29: 181
[11]	Zener C. J Appl Phys, 1949; 20: 950
[12]	Christian J W. The Theory of Transformations in Metals and Alloys. Oxford: Pergamon Press, 2002: 1
[13]	Sietsma J, van der Zwaag S. Acta Mater, 2004; 52: 4143
[14]	Xu Z Y. Principle of Phase Transformation. Beijing: Science Press, 1988: 1 (徐祖耀. 相变原理. 北京: 科学出版社, 1988: 1)
[15]	Fan K, Liu F, Liu X N, Zhang Y X, Yang G C, Zhou Y H. Acta Mater, 2008; 56: 4309
[16]	Offerman S E, van Dijk N H, Sietsma J, Lauridsen E M, Margulies L, Grigull S, Poulsen H F, van der Zwaag S. Acta Mater, 2004; 52: 4757
[17]	Wang H F, Liu F, Zhang T, Yang G C, Zhou Y H. Acta Mater, 2009; 57: 3072
[18]	Krielaart G P, Sietsma J, van der Zwaag S. Mater Sci Eng, 1997; 237: 216
[19]	Serajzadeh S. J Mater Process Technol, 2004; 146: 311
[20]	Hawbolt E, Chau B, Brimacombe J. Metall Trans, 1985; 16A: 565
[21]	Johnson J W, Mehl R F. Trans AIME, 1939; 135: 416
[22]	Avrami M. J Chem Phys, 1939; 7: 1103
[23]	?gren J. Acta Metall Mater, 1982; 30: 841
[24]	Kumar M, Sasikumar R, Nair P K. Acta Mater, 1998; 46: 6291
[25]	Offerman S, van Dijk N, Sistsma J, Grigull S, Lauridsen E M, Margulies L, Poulsen H F, Rekveldt M T, van der Zwaag S. Science, 2002; 298: 1003

[1]	DING Hua, ZHANG Yu, CAI Minghui, TANG Zhengyou. Research Progress and Prospects of Austenite-Based Fe-Mn-Al-C Lightweight Steels[J]. 金属学报, 2023, 59(8): 1027-1041.
[2]	WANG Bin, NIU Mengchao, WANG Wei, JIANG Tao, LUAN Junhua, YANG Ke. Microstructure and Strength-Toughness of a Cu-Contained Maraging Stainless Steel[J]. 金属学报, 2023, 59(5): 636-646.
[3]	HOU Xuru, ZHAO Lin, REN Shubin, PENG Yun, MA Chengyong, TIAN Zhiling. Effect of Heat Input on Microstructure and Mechanical Properties of Marine High Strength Steel Fabricated by Wire Arc Additive Manufacturing[J]. 金属学报, 2023, 59(10): 1311-1323.
[4]	SHEN Guohui, HU Bin, YANG Zhanbing, LUO Haiwen. Influence of Tempering Temperature on Mechanical Properties and Microstructures of High-Al-Contained Medium Mn Steel Having δ-Ferrite[J]. 金属学报, 2022, 58(2): 165-174.
[5]	LI Xueda, LI Chunyu, CAO Ning, LIN Xueqiang, SUN Jianbo. Crystallography of Reverted Austenite in the Intercritically Reheated Coarse-Grained Heat-Affected Zone of High Strength Pipeline Steel[J]. 金属学报, 2021, 57(8): 967-976.
[6]	JIANG Zhonghua, DU Junyi, WANG Pei, ZHENG Jianneng, LI Dianzhong, LI Yiyi. Mechanism of Improving the Impact Toughness of SA508-3 Steel Used for Nuclear Power by Pre-Transformation of M-A Islands[J]. 金属学报, 2021, 57(7): 891-902.
[7]	LIU Man, HU Haijiang, TIAN Junyu, XU Guang. Effect of Ausforming on the Microstructures and Mechanical Properties of an Ultra-High Strength Bainitic Steel[J]. 金属学报, 2021, 57(6): 749-756.
[8]	WANG Jinliang, WANG Chenchong, HUANG Minghao, HU Jun, XU Wei. The Effects and Mechanisms of Pre-Deformation with Low Strain on Temperature-Induced Martensitic Transformation[J]. 金属学报, 2021, 57(5): 575-585.
[9]	CHEN Wenxiong, HU Baojia, JIA Chunni, ZHENG Chengwu, LI Dianzhong. Post-Dynamic Softening of Austenite in a Ni-30%Fe Model Alloy After Hot Deformation[J]. 金属学报, 2020, 56(6): 874-884.
[10]	XU Wei,HUANG Minghao,WANG Jinliang,SHEN Chunguang,ZHANG Tianyu,WANG Chenchong. Review: Relations Between Metastable Austenite and Fatigue Behavior of Steels[J]. 金属学报, 2020, 56(4): 459-475.
[11]	PENG Yun,SONG Liang,ZHAO Lin,MA Chengyong,ZHAO Haiyan,TIAN Zhiling. Research Status of Weldability of Advanced Steel[J]. 金属学报, 2020, 56(4): 601-618.
[12]	LIU Zhenbao,LIANG Jianxiong,SU Jie,WANG Xiaohui,SUN Yongqing,WANG Changjun,YANG Zhiyong. Research and Application Progress in Ultra-HighStrength Stainless Steel[J]. 金属学报, 2020, 56(4): 549-557.
[13]	JIANG Yi,CHENG Manlang,JIANG Haihong,ZHOU Qinglong,JIANG Meixue,JIANG Laizhu,JIANG Yiming. Microstructure and Properties of 08Cr19Mn6Ni3Cu2N (QN1803) High Strength Nitrogen Alloyed LowNickel Austenitic Stainless Steel[J]. 金属学报, 2020, 56(4): 642-652.
[14]	LUO Haiwen,SHEN Guohui. Progress and Perspective of Ultra-High Strength Steels Having High Toughness[J]. 金属学报, 2020, 56(4): 494-512.
[15]	WANG Cunyu,CHANG Ying,ZHOU Fengluan,CAO Wenquan,DONG Han,WENG Yuqing. M³ Microstructure Control Theory and Technology of the Third-Generation Automotive Steels with HighStrength and High Ductility[J]. 金属学报, 2020, 56(4): 400-410.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Shared

Discussed