Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization

To address the failure of 25MnB crawler track steel due to insufficient strength and toughness, this study designed a new type of 25MnB crawler track steel and investigated the effects of the Nb content on its mechanical properties, microstructure, dislocation evolution, and precipitation behavior....

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Main Authors: Zixun He, Jianjing Wang, Houxin Wang, Yajie Cui, Zhengbing Meng, Jiangbo Deng, Meiqiao Wu, Chaoyang Zhou, Xinbin Liu
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/5/490
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author Zixun He
Jianjing Wang
Houxin Wang
Yajie Cui
Zhengbing Meng
Jiangbo Deng
Meiqiao Wu
Chaoyang Zhou
Xinbin Liu
author_facet Zixun He
Jianjing Wang
Houxin Wang
Yajie Cui
Zhengbing Meng
Jiangbo Deng
Meiqiao Wu
Chaoyang Zhou
Xinbin Liu
author_sort Zixun He
collection DOAJ
description To address the failure of 25MnB crawler track steel due to insufficient strength and toughness, this study designed a new type of 25MnB crawler track steel and investigated the effects of the Nb content on its mechanical properties, microstructure, dislocation evolution, and precipitation behavior. The experimental results show that, compared to 25MnB steel without Nb, the addition of 0.03% Nb significantly increased the yield strength of the experimental steel to 1450 MPa, with an elongation rate of 15.9%. The room-temperature impact energy showed a slight improvement, while the low-temperature impact absorption energy improved notably, reaching 36 J at −40 °C. The microstructural characterization and analysis revealed that increasing the Nb content refined the effective grain size of prior austenite and martensite. The (Nb, Ti)C precipitates provided a higher precipitation driving force, promoting the formation of precipitates and increasing the average dislocation density. Additionally, the increased proportion of high-angle grain boundaries (HAGBs) enabled grain boundaries and precipitates to jointly hinder crack propagation. This study demonstrates that Nb-Ti microalloying can effectively enhance the strength, toughness, and plasticity of track steel, demonstrating promising application prospects.
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issn 2075-4701
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spelling doaj-art-591333ac9ca14abe96f6ed9bc278b03f2025-08-20T01:56:20ZengMDPI AGMetals2075-47012025-04-0115549010.3390/met15050490Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural CharacterizationZixun He0Jianjing Wang1Houxin Wang2Yajie Cui3Zhengbing Meng4Jiangbo Deng5Meiqiao Wu6Chaoyang Zhou7Xinbin Liu8Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004, ChinaResearch Institute of Shandong Iron and Steel Co., Ltd., Jinan 271104, ChinaCITIC Metals Co., Ltd., Beijing 100004, ChinaKey Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004, ChinaKey Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004, ChinaKey Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004, ChinaKey Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004, ChinaSchool of Metallurgical Engineering, Jiangsu University of Science and Technology, Zhangjiagang 215600, ChinaSchool of Intelligent Manufacturing and Mechanical Engineering, Hunan Institute of Technology, Hengyang 421002, ChinaTo address the failure of 25MnB crawler track steel due to insufficient strength and toughness, this study designed a new type of 25MnB crawler track steel and investigated the effects of the Nb content on its mechanical properties, microstructure, dislocation evolution, and precipitation behavior. The experimental results show that, compared to 25MnB steel without Nb, the addition of 0.03% Nb significantly increased the yield strength of the experimental steel to 1450 MPa, with an elongation rate of 15.9%. The room-temperature impact energy showed a slight improvement, while the low-temperature impact absorption energy improved notably, reaching 36 J at −40 °C. The microstructural characterization and analysis revealed that increasing the Nb content refined the effective grain size of prior austenite and martensite. The (Nb, Ti)C precipitates provided a higher precipitation driving force, promoting the formation of precipitates and increasing the average dislocation density. Additionally, the increased proportion of high-angle grain boundaries (HAGBs) enabled grain boundaries and precipitates to jointly hinder crack propagation. This study demonstrates that Nb-Ti microalloying can effectively enhance the strength, toughness, and plasticity of track steel, demonstrating promising application prospects.https://www.mdpi.com/2075-4701/15/5/490microalloying25MnB crawler track steelmechanical propertiesNb contentprecipitation kineticsdislocation movement
spellingShingle Zixun He
Jianjing Wang
Houxin Wang
Yajie Cui
Zhengbing Meng
Jiangbo Deng
Meiqiao Wu
Chaoyang Zhou
Xinbin Liu
Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization
Metals
microalloying
25MnB crawler track steel
mechanical properties
Nb content
precipitation kinetics
dislocation movement
title Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization
title_full Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization
title_fullStr Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization
title_full_unstemmed Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization
title_short Effect of Nb Content on Strength and Toughness of 25MnB Crawler Steel and Its Microstructural Characterization
title_sort effect of nb content on strength and toughness of 25mnb crawler steel and its microstructural characterization
topic microalloying
25MnB crawler track steel
mechanical properties
Nb content
precipitation kinetics
dislocation movement
url https://www.mdpi.com/2075-4701/15/5/490
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