1 School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China 2 State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072, China 3 Steelmaking Research Department, Research Institute, Baoshan Iron and Steel Co., Ltd., Shanghai 201999, China
Effect of Mg addition on formation of intragranular acicular ferrite in heat-affected zone of steel plate after high-heat-input welding
1 School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China 2 State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072, China 3 Steelmaking Research Department, Research Institute, Baoshan Iron and Steel Co., Ltd., Shanghai 201999, China
ժҪ The effects of Mg content, inclusion size, and austenite grain size on the intragranular acicular ferrite (IAF) nucleation in heat-affected zone of steel plate after high-heat-input welding of 400 kJ/cm were investigated by welding simulation and observation using a scanning electron microscope equipped with an energy dispersive spectrometer and an optical microscope. The IAFs are observed in steel with Mg addition, and the volume fraction of IAF is as high as 55.4% in the steel containing 0.0027 mass% Mg. The MgO�CAl2O3�CTi2O3�CMnS inclusions with size around 2 lm are effective nucleation sites for IAF, whereas Al2O3�CMnS inclusions are impotent to nucleate the acicular ferrite. The prior-austenite grain (PAG) size distribution in low Mg steel is similar to that in steel without Mg addition. The austenite grain with size about 200 lm is favorable for the IAF formation. In the steel with high Mg content of 0.0099%, the growth of PAG is greatly inhibited, and PAG sizes are smaller than 100 lm. Therefore, the nucleation of IAF can hardly be observed.
Abstract��The effects of Mg content, inclusion size, and austenite grain size on the intragranular acicular ferrite (IAF) nucleation in heat-affected zone of steel plate after high-heat-input welding of 400 kJ/cm were investigated by welding simulation and observation using a scanning electron microscope equipped with an energy dispersive spectrometer and an optical microscope. The IAFs are observed in steel with Mg addition, and the volume fraction of IAF is as high as 55.4% in the steel containing 0.0027 mass% Mg. The MgO�CAl2O3�CTi2O3�CMnS inclusions with size around 2 lm are effective nucleation sites for IAF, whereas Al2O3�CMnS inclusions are impotent to nucleate the acicular ferrite. The prior-austenite grain (PAG) size distribution in low Mg steel is similar to that in steel without Mg addition. The austenite grain with size about 200 lm is favorable for the IAF formation. In the steel with high Mg content of 0.0099%, the growth of PAG is greatly inhibited, and PAG sizes are smaller than 100 lm. Therefore, the nucleation of IAF can hardly be observed.
Long-yun Xu, ? Jian Yang ? Rui-zhi Wang ? Wan-lin Wang ? Yu-nan Wang. Effect of Mg addition on formation of intragranular acicular ferrite in heat-affected zone of steel plate after high-heat-input welding[J].Journal of Iron and Steel Research International, 2018, 25(4): 433-441.
Long-yun Xu, ? Jian Yang ? Rui-zhi Wang ? Wan-lin Wang ? Yu-nan Wang. Effect of Mg addition on formation of intragranular acicular ferrite in heat-affected zone of steel plate after high-heat-input welding. , 2018, 25(4): 433-441.
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