Quenching Deformation of the 16MnCrS5 Gear Steel for Automobile
QU Xiaobo1(), AN Jinmin1, WANG Lin2, LI Xi2()
1 Jiangsu Yonggang Group Co. Ltd., Suzhou 215628, China 2 School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Cite this article:
QU Xiaobo, AN Jinmin, WANG Lin, LI Xi. Quenching Deformation of the 16MnCrS5 Gear Steel for Automobile. Acta Metall Sin, 2025, 61(4): 597-607.
The 16MnCrS5 gear steel, known for its exceptional machinability and hardenability, is commonly utilized in the production of gears and worms in the automotive industry. However, the quenching process of this steel tends to provoke deformation, leading to increased wear and an inability of gear teeth to mesh. This issue seriously restricts the broader use of 16MnCrS5 gear steel. This study explores the quenching deformation of 16MnCrS5 gear steel through a combination of experimental research and numerical simulation to provide theoretical insight to mitigate this deformation in industrial production. The quenching deformations of C-notch samples derived from 16MnCrS5 gear steel, varying in grain size, banded structures, and hardenabilities were first measured. Subsequently, employing the deform finite element analysis software, the temperature field, stress field, and phase field during the quenching of these samples were simulated, thereby visually portraying the corresponding quenching deformation processes. The results indicate that the quenching deformation of 16MnCrS5 gear steel escalates with an increase in grain size and the proportion of banded structures. For instance, the sample with a grain size of 75 μm demonstrated nearly double the quenching deformation of the sample with a grain size of 22 μm. Moreover, when the grade of the banded structure surpasses 3, the quenching deformation of the sample markedly increases. Concurrently, the results revealed a positive correlation between quenching deformation and hardenability of 16MnCrS5 gear steel. Specifically, when the hardness at 9 mm from the quenching end (J9) > 32.2 HRC, the sample's core is largely martensitic, showing a stronger correlation with hardenability. Conversely, when J9 ≤ 32.2 HRC, there is noticeable bainitic transformation in the sample's core, resulting in a weaker correlation between the quenching deformation and hardenability. The experimental research and numerical simulations suggest that the intrinsic mechanism of quenching deformation in 16MnCrS5 gear steel is mainly attributable to thermal stress and martensitic transformation-induced stress. Notably, the temporal and spatial inhomogeneity of the martensite transformation in time and spatial distribution is the predominant factor affecting the quenching deformation of 16MnCrS5 gear steel.
Fig.1 C-notch specimen for the measurement of quenching deformation and 5 characteristic points (P1-P5) of the geometrical model for numerical simulation (unit: mm. w—width)
Fig.2 Measurements of the phase-transformation parameters of 16MnCrS5 gear steel (a) time-temperature-transformation (TTT) curves (A, F, P, B, and M denote austenite, ferrite, pearlite, bainite, and martensite, respectively; Ms, Mf, Ac1, and Ac3 are martensite transformation start temperature, martensite transformation finish temperature, start temperature of transformation from pearlite to austenite during heating, and finish temperature of transformation from ferrite to austenite during heating, respectively. 1% and 99% represent the transformation variables of 1% and 99%, respectively) (b) continuous cooling transformation (CCT) curves
Fig.3 Tensile true stress-strain curve at ambient temperature (a) and the simulated flow stress curves of the theoretical constituent phases (martensite, bainite, austenite, ferrite, and pearlite) at 500 oC (b) for 16MnCrS5 gear steel with a grain size of 22 μm
Fig.4 Jominy hardness curves of the 16MnCrS5 gear steels with different hardenabilities (J9 represents the hardness at 9 mm from the quenching end)
Fig.5 OM images of the 16MnCrS5 original sample (a) and that after annealing at 1150 oC for 10 min (b) and 60 min (c)
Fig.6 Quenching deformations of the 16MnCrS5 C-notch samples obtained by experiment and simulation as function of grain size
Fig.7 Numerical simulated temperature (a) and struc-tural stress (b) change curves as function of time at P3 of samples with different grain sizes during quenching (Inset in Fig.7a is the close-up view of the purple frame region)
Fig.8 OM images showing the banded structure morphologies of the 16MnCrS5 samples after hot rolling with water-colling (a), air-cooling (b), and furnace cooling (c)
Fig.9 Quenching deformations of the 16MnCrS5 C-notch samples obtained by experiment and simulation as function of band structure grade (TD—transverse direction, RD—rolling direction)
Fig.10 Jominy hardness curves of the 16MnCrS5 and TL4227 gear steels
Fig.11 Quenching deformations of the 16MnCrS5 and TL4227 C-notch samples obtained by experiment and that of the 16MnCrS5 structural models with different hardenabilities calculated by simulation (a), martensite transformation distribution of the sample with J9 = 38.8 HRC (b), and bainite transformation distribution of the sample with J9 = 32.2 HRC (c)
Fig.12 Numerical simulated martensite volume fraction (a) and structural stress (b) change curves as function of time at P4 of the C-notch samples with different hardenabilities during quenching
Fig.13 Analyses of quenching deformation of 16MnCrS5 gear steel (a) curves of quenching deformation of the 5 characteristic points with time (b) temperature difference between notch and core changes over time (c) variation of martensite proportion with time at P4
Fig.14 Microstructure characterizations of the quench-ing deformed 16MnCrS5 gear steel (a) SEM image (b) EBSD inverse pole figure (IPF) grain orientation map (c) corresponding kernel average misorientation (KAM) map
1
Lin C, Zhao M J, Pan H, et al. Blending gear shift strategy design and comparison study for a battery electric city bus with AMT [J]. Energy, 2019, 185: 1
2
Arunachalam R, Krishnan P K, Muraliraja R. A review on the production of metal matrix composites through stir casting—Furnace design, properties, challenges, and research opportunities [J]. J. Manuf. Processes, 2019, 42: 213
3
Gupta K, Jain N K, Laubscher R F. Spark erosion machining of miniature gears: A critical review [J]. Int. J. Adv. Manuf. Technol., 2015, 80: 1863
4
Xiao N, Hui W J, Zhang Y J, et al. Hydrogen embrittlement behavior of a vacuum-carburized gear steel [J]. Acta Metall. Sin., 2021, 57: 977
doi: 10.11900/0412.1961.2020.00363
Inoue A, Takeuchi A. Recent development and application products of bulk glassy alloys [J]. Acta Mater., 2011, 59: 2243
6
Fang X R, Liu L, Xu H H, et al. Effect of pre-heat treatment before carburizing on distortion of gear shaft made of 17CrNiMo6 steel [J]. Heat Treat. Met., 2022, 47(3): 113
doi: 10.13251/j.issn.0254-6051.2022.03.022
Zhang G Q. Microstructure and distortion of niobium-containing 18CrNiMo7-6 gear steel after high-temperature carburization [D]. Beijing: Central Iron & Steel Research Institute, 2021
Cao Y G. Study on hardenability, heat treatment distortion and fatigue property of carburized gear steels [D]. Beijing: Central Iron & Steel Research Institute, 2017
曹燕光. 渗碳齿轮钢淬透性及其热处理变形和疲劳性能研究 [D]. 北京: 钢铁研究总院, 2017
9
Liu J M. Research on abnormal deformation of automobile gear during carburizing and quenching heat treatment [J]. Met. Work., 2005, (11): 40
刘建明. 汽车齿轮渗碳淬火热处理异常变形的研究 [J]. 机械工人, 2005, (11): 40
10
An J M, Qin M, Ding Y. Effect of austenite grain size on heat treatment distortion automotive gear steels [J]. Heat Treat., 2013, 28(3): 48
Wang J, Dang S E, Fan Z J, et al. Microstructure homogenization of 17CrNiMo6 gear steel [J]. Heat Treat. Met., 2022, 47(11): 126
doi: 10.13251/j.issn.0254-6051.2022.11.022
Lai H Z. Research on forming mechanism of banded structure in 60Si2Mn spring flat steel and its influence on mechanical properties [D]. Ganzhou: Jiangxi University of Science and Technology, 2014
Wang Z Y, Xing Z G, Wang H D, et al. The relationship between inclusions characteristic parameters and bending fatigue performance of 20Cr2Ni4A gear steel [J]. Int. J. Fatigue, 2022, 155: 106594
15
Wang B X, Liu X H, Wang G D. Dynamic recrystallisation behaviour and microstructural evolution in a Mn-Cr gear steel [J]. Mater. Sci. Technol., 2005, 21: 798
16
Huang J B. Research on the hardenability and phase transformation behavior of heavy transmission gear steel [D]. Beijing: Beijing Jiaotong University, 2017
黄金宝. 重载传动齿轮钢淬透性及相变变形规律的研究 [D]. 北京: 北京交通大学, 2017
17
Yang C, An J M, Huan Z Z. Numerical simulation of banded microstructure on quenching distortion in gear steel based on Deform [J]. Bao-Steel Technol., 2016, (3): 16
Seo H, Lee D G, Park J, et al. Quench hardening effect of gray iron brake discs on particulate matter emission [J]. Wear, 2023, 523: 204781
19
Zhang W H. A study on fabrication, heat-treatments and mechanical properties of V-Nb microalloyed gear steel [D]. Wuhan: Wuhan University of Science and Technology, 2007
An X X, Tian Y, Wang H J, et al. Suppression of austenite grain coarsening by using Nb-Ti microalloying in high temperature carburizing of a gear steel [J]. Adv. Eng. Mater., 2019, 21: 1900132
21
O'Brien E C H C, Yeddu H K. Multi-length scale modeling of carburization, martensitic microstructure evolution and fatigue properties of steel gears [J]. J. Mater. Sci. Technol., 2020, 49: 157
doi: 10.1016/j.jmst.2019.10.044
22
Wang B, He Y P, Liu Y, et al. Mechanism of the microstructural evolution of 18Cr2Ni4WA steel during vacuum low-pressure carburizing heat treatment and its effect on case hardness [J]. Materials, 2020, 13: 2352
23
Wang Y B. A study on hardenability and band structure of 20CrMoH gear steel [D]. Kunmin: Kunming University of Science and Technology, 2010
王彦彬. 20CrMoH齿轮钢的淬透性及带状组织研究 [D]. 昆明: 昆明理工大学, 2010
24
Hu S B. A simple conversion formule of HV and HRC mutual [J]. J. Hubei Univ. Auto. Technol., 1992, (2): 64
Koistine D F, Marburger R E. A general equation prescribing the extent of the austenite-martensite transformation in pure iron-carbon alloys and plain carbon steels [J]. Acta Metall., 1959, 7: 59
26
Denis S, Gautier E, Simon A, et al. Stress-phase-transformation interactions—Basic principles, modelling, and calculation of internal stresses [J]. Mater. Sci. Technol., 1985, 1: 805
27
Li H B, Zheng M Y, Tian W, et al. Flow stress constitutive equation of M50NiL gear steel based on Johnson-Cook model [J]. Mater. Mech. Eng., 2016, 40(11): 31
Rego R, Löpenhaus C, Gomes J, et al. Residual stress interaction on gear manufacturing [J]. J. Mater. Process. Technol., 2018, 252: 249
29
Chen W, He X F, Yu W C, et al. Nano- and microhardness distribution in the carburized case of Nb-microalloyed gear steel [J]. J. Mater. Eng. Perform., 2020, 29: 4626
doi: 10.1007/s11665-020-04992-7
30
Du Y F. Effects of heat treatment and hot processing on banded structure characteristics and mechanical properties of PCrNi3MoV steel [D]. Taiyuan: North University of China, 2021