Study on the Influences of Adding Rare Earth Ce on the Precipitation Behaviors of TiN Inclusions in 20CrMnTi

Jian Wang; Jun Peng; Lixia Liu; Fang Zhang; Jihua Peng; Hao Tang; Jie Zheng; Shengli An

doi:10.3390/ma16165598

Study on the Influences of Adding Rare Earth Ce on the Precipitation Behaviors of TiN Inclusions in 20CrMnTi

Materials (Basel). 2023 Aug 12;16(16):5598. doi: 10.3390/ma16165598.

Authors

Jian Wang^{1

2

3}, Jun Peng^{1

2

3

4}, Lixia Liu^{1

2

3}, Fang Zhang^{1

2

3}, Jihua Peng^{1

2

3}, Hao Tang^{1

2

3}, Jie Zheng^{1

2

3}, Shengli An^{1

2

3}

Affiliations

¹ School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, China.
² Inner Mongolia Key Laboratory of Advanced Ceramic Materials and Devices, Inner Mongolia University of Science and Technology, Baotou 014010, China.
³ Key Laboratory of Green Extraction & Efficient Utilization of Light Rare-Earth Resources, Ministry of Education, Inner Mongolia University of Science and Technology, Baotou 014010, China.
⁴ School of Rare Earth Research and Development, Inner Mongolia University of Science and Technology, Baotou 014010, China.

Abstract

The morphologies and sizes of TiN inclusions in gear steel 20CrMnTi have a significant impact on its service performance. This paper selects rare earth Ce to modify TiN inclusions in 20CrMnTi. The inclusions are analyzed by SEM (scanning electron microscope), EBSD (electron back-scattered diffraction), EDS (energy disperse spectroscopy), and OTS statistical software, and Thermo-Calc software is used to calculate the inclusion formations. The inclusions of MgAlO₄-Ce and CeAlO₃ can be formed when rare earth Ce is added into 20CrMnTi, which becomes TiN nucleation core after precipitation. Without the addition of rare earth Ce, square TiN inclusions ranging from 2 to 5 μm account for 60% of the total inclusions in 20CrMnTi. After adding rare earth Ce, the TiN inclusions in 20CrMnTiCe account for 36.7% of the total inclusions. Due to the new phase formations of MgAlO₄-TiN and CeAlO₃-TiN with sizes less than 2 μm, the titanium-containing inclusions are refined. Fatigue tests are conducted on the steels before and after the addition of Ce. The average fatigue lives of 20CrMnTi do not reach 10⁷ times, and the deviations between the maximum and minimum fatigue lives are great. Large-sized TiN are the main inclusions that affect the fatigue performance of 20CrMnTi. The average fatigue lives of 20CrMnTiCe exceed 10⁷ times, and the deviations of the fatigue lives are smaller than those of 20CrMnTi.

Keywords: TiN inclusions; gear steel; precipitation; rare earth Ce.

Abstract

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