1 The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China 2 Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China 3 School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China 4 The Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology, Yangtze Normal University, Chongqing 408100, China
Effect of heat input on microstructure and toughness of rare earthcontained C�CMn steel
1 The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China 2 Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China 3 School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China 4 The Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology, Yangtze Normal University, Chongqing 408100, China
ժҪ Gleeble-1500D thermal simulator was used to simulate the thermal cycle of different welding processes in C�CMn steel. The toughness of steel matrix and heat-affected zone (HAZ) was investigated, and the microstructure and inclusion were characterized as well. The results showed that the welding process has a great influence on the microstructure in HAZ. When t8/5 (the cooling time from 800 to 500 C) value of the welding process is less than 111 s, the microstructure in HAZ is mainly bainite/Widmansta��tten in spite of the addition of rare earth. However, when t8/5 value is more than 250 s, there are a lot of acicular ferrites in the steel containing rare earth, while the main microstructures are grain boundary ferrite and bainite/Widmansta��tten in the steel without rare earth. The impact toughness of the HAZ at ambient temperature first decreases and then increases with the increase in t8/5 value. The impact toughness is the worst when t8/5 value is 111 s. Rare earth can improve the impact performance of HAZ at ambient temperature, especially when t8/5 value of the welding process is 445 s. After the rare earth treatment, the cooling rate of forming acicular ferrite is about 0.5�C7.5 C/s. Acicular ferrite can form even during the welding process with larger t8/5 value up to 600 s in rare earth-treated steel.
Abstract��Gleeble-1500D thermal simulator was used to simulate the thermal cycle of different welding processes in C�CMn steel. The toughness of steel matrix and heat-affected zone (HAZ) was investigated, and the microstructure and inclusion were characterized as well. The results showed that the welding process has a great influence on the microstructure in HAZ. When t8/5 (the cooling time from 800 to 500 C) value of the welding process is less than 111 s, the microstructure in HAZ is mainly bainite/Widmansta��tten in spite of the addition of rare earth. However, when t8/5 value is more than 250 s, there are a lot of acicular ferrites in the steel containing rare earth, while the main microstructures are grain boundary ferrite and bainite/Widmansta��tten in the steel without rare earth. The impact toughness of the HAZ at ambient temperature first decreases and then increases with the increase in t8/5 value. The impact toughness is the worst when t8/5 value is 111 s. Rare earth can improve the impact performance of HAZ at ambient temperature, especially when t8/5 value of the welding process is 445 s. After the rare earth treatment, the cooling rate of forming acicular ferrite is about 0.5�C7.5 C/s. Acicular ferrite can form even during the welding process with larger t8/5 value up to 600 s in rare earth-treated steel.
Ming-ming Song, ? Bo Song ? Sheng-hua Zhang ? Zhan-bing Yang ? Zheng-liang Xue, ? Sheng-qiang Song, ? Run-sheng Xu, ? Zhi-bo Tong. Effect of heat input on microstructure and toughness of rare earthcontained C�CMn steel[J].Journal of Iron and Steel Research International, 2018, 25(10): 1033-1042.
Ming-ming Song, ? Bo Song ? Sheng-hua Zhang ? Zhan-bing Yang ? Zheng-liang Xue, ? Sheng-qiang Song, ? Run-sheng Xu, ? Zhi-bo Tong. Effect of heat input on microstructure and toughness of rare earthcontained C�CMn steel. , 2018, 25(10): 1033-1042.
2018, Vol. 25 
