Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel
In this study, X80 pipeline steel is prepared with different Nb contents through the thermo-mechanically controlled rolling process. The effects of using two different Nb contents on the impact toughness and microstructure of the pipeline steel are examined using various experimental techniques. The...
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MDPI AG
2023-12-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/14/1/42 |
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| author | Jinxing Jiang Zhongde Zhang Kai Guo Yingping Guan Liangzeng Yuan Qingfeng Wang |
| author_facet | Jinxing Jiang Zhongde Zhang Kai Guo Yingping Guan Liangzeng Yuan Qingfeng Wang |
| author_sort | Jinxing Jiang |
| collection | DOAJ |
| description | In this study, X80 pipeline steel is prepared with different Nb contents through the thermo-mechanically controlled rolling process. The effects of using two different Nb contents on the impact toughness and microstructure of the pipeline steel are examined using various experimental techniques. The results show that with the increase in Nb content, the transformation temperature Ar<sub>3</sub> decreases, and the nucleation and growth of bainitic ferrite with lath features (LB) are promoted, while those of granular bainite (GB) are inhibited. In addition, the stability of the austenite phase increases with the increase in Nb content. Therefore, the volume fractions of LB and martensite–austenite (M/A) constituents increase, while the proportion of high-angle grain boundaries (HAGBs) decreases. The impact energy of pipeline steel at −45 °C is closely related to the Nb content. Specifically, the impact energy decreases from 217 J at 0.05 wt.% Nb to 88 J at 0.08 wt.% Nb. The cracks are preferentially formed near the M/A constituents, and the HAGBs significantly inhibit the crack propagation. The steel with 0.05 wt.% Nb has a lower content of M/A constituents and a higher proportion of HAGBs than the one with 0.08 wt.% Nb. In addition, as the Nb content increases, the crack initiation energy and the crack propagation energy decrease. Thus, the 0.05 wt.% Nb steel has a higher low-temperature impact energy. |
| first_indexed | 2024-03-08T10:40:30Z |
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| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-08T10:40:30Z |
| publishDate | 2023-12-01 |
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| spelling | doaj.art-85a404024eae41c9ad50c4190f696e6c2024-01-26T17:40:47ZengMDPI AGMetals2075-47012023-12-011414210.3390/met14010042Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline SteelJinxing Jiang0Zhongde Zhang1Kai Guo2Yingping Guan3Liangzeng Yuan4Qingfeng Wang5School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, ChinaLaboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, ChinaLaboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, ChinaSchool of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, ChinaLaboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, ChinaLaboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, ChinaIn this study, X80 pipeline steel is prepared with different Nb contents through the thermo-mechanically controlled rolling process. The effects of using two different Nb contents on the impact toughness and microstructure of the pipeline steel are examined using various experimental techniques. The results show that with the increase in Nb content, the transformation temperature Ar<sub>3</sub> decreases, and the nucleation and growth of bainitic ferrite with lath features (LB) are promoted, while those of granular bainite (GB) are inhibited. In addition, the stability of the austenite phase increases with the increase in Nb content. Therefore, the volume fractions of LB and martensite–austenite (M/A) constituents increase, while the proportion of high-angle grain boundaries (HAGBs) decreases. The impact energy of pipeline steel at −45 °C is closely related to the Nb content. Specifically, the impact energy decreases from 217 J at 0.05 wt.% Nb to 88 J at 0.08 wt.% Nb. The cracks are preferentially formed near the M/A constituents, and the HAGBs significantly inhibit the crack propagation. The steel with 0.05 wt.% Nb has a lower content of M/A constituents and a higher proportion of HAGBs than the one with 0.08 wt.% Nb. In addition, as the Nb content increases, the crack initiation energy and the crack propagation energy decrease. Thus, the 0.05 wt.% Nb steel has a higher low-temperature impact energy.https://www.mdpi.com/2075-4701/14/1/42pipeline steelmicroalloyingmicrostructureimpact toughness |
| spellingShingle | Jinxing Jiang Zhongde Zhang Kai Guo Yingping Guan Liangzeng Yuan Qingfeng Wang Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel Metals pipeline steel microalloying microstructure impact toughness |
| title | Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel |
| title_full | Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel |
| title_fullStr | Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel |
| title_full_unstemmed | Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel |
| title_short | Effect of Nb Content on the Microstructure and Impact Toughness of High-Strength Pipeline Steel |
| title_sort | effect of nb content on the microstructure and impact toughness of high strength pipeline steel |
| topic | pipeline steel microalloying microstructure impact toughness |
| url | https://www.mdpi.com/2075-4701/14/1/42 |
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