Relationship between crystallographic structure of complex inclusions MgAl2O4/Ti2O3/MnS and improved toughness of heat-affected zone in shipbuilding steel
1 College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, Hebei, China; 2 College of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, Hebei, China; 3 China Analysis and Testing Center, North China University of Science and Technology, Tangshan 063210, Hebei, China; 4 MCC Capital Engineering & Research Incorporation Limited, Metallurgical Engineering Consulting and Design Division, Beijing 100176, China;
Relationship between crystallographic structure of complex inclusions MgAl2O4/Ti2O3/MnS and improved toughness of heat-affected zone in shipbuilding steel
1 College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, Hebei, China; 2 College of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, Hebei, China; 3 China Analysis and Testing Center, North China University of Science and Technology, Tangshan 063210, Hebei, China; 4 MCC Capital Engineering & Research Incorporation Limited, Metallurgical Engineering Consulting and Design Division, Beijing 100176, China;
摘要 In accordance with the minimum degree of disregistry mechanism in oxide metallurgy, the intragranular acicular ferrite (IAF) generated by microalloying elements in austenite was studied. Herein, the effect of Mg treatment on the microstructure and toughness of the heat-affected zone (HAZ) in shipbuilding steel was investigated. Mg treatment produced inclusions that influenced the formation of acicular ferrite in the microstructure. This refined the HAZ microstructure and improved its toughness. Electron backscatter diffraction was used to determine the oxides of titanium and the MgO Al2O3 or MgAl2O4 complex inclusions that induced the formation of IAF. MnS precipitated on MgAl2O4 on a specific habit plane and in a specific direction. MnS had a specific orientation relationship with MgAl2O4, i.e., f100gMgAl2O4 //{100}MnS. The 35-mm-thick plate obtained in the industrial test after welding at a welding heat input of 120 kJ/cm had an average impact absorbed energy of 282.7 J at - 40 ℃ and 2 mm from the weld joint in the HAZ. The twodimensional disregistry index between inclusions can be used as the basis for controlling their distribution and adsorption force. Microalloy addition in the order of Al–Mg–Ti is key to obtaining abundant dispersion and fine nucleation in austenite.
Abstract：In accordance with the minimum degree of disregistry mechanism in oxide metallurgy, the intragranular acicular ferrite (IAF) generated by microalloying elements in austenite was studied. Herein, the effect of Mg treatment on the microstructure and toughness of the heat-affected zone (HAZ) in shipbuilding steel was investigated. Mg treatment produced inclusions that influenced the formation of acicular ferrite in the microstructure. This refined the HAZ microstructure and improved its toughness. Electron backscatter diffraction was used to determine the oxides of titanium and the MgO Al2O3 or MgAl2O4 complex inclusions that induced the formation of IAF. MnS precipitated on MgAl2O4 on a specific habit plane and in a specific direction. MnS had a specific orientation relationship with MgAl2O4, i.e., f100gMgAl2O4 //{100}MnS. The 35-mm-thick plate obtained in the industrial test after welding at a welding heat input of 120 kJ/cm had an average impact absorbed energy of 282.7 J at - 40 ℃ and 2 mm from the weld joint in the HAZ. The twodimensional disregistry index between inclusions can be used as the basis for controlling their distribution and adsorption force. Microalloy addition in the order of Al–Mg–Ti is key to obtaining abundant dispersion and fine nucleation in austenite.
Yan Wang,Li-guang Zhu,Jin-xia Huo, et al. Relationship between crystallographic structure of complex inclusions MgAl2O4/Ti2O3/MnS and improved toughness of heat-affected zone in shipbuilding steel[J]. Journal of Iron and Steel Research International, 2022, 29(08): 1277-1290.
2022, Vol. 29 
