Abstract:High strength and low iron loss are required for the driving motors of new energy vehicles. However, it is challenging to achieve both.The synergistic optimization of both high strength and low iron loss of non-oriented silicon steels was realized by adjusting the microstructure and nano-B2 Cu-rich precipitates which have a low mismatch with the matrix. The effect of annealing temperature on the microstructure, precipitates, strength, and iron loss of Cu-containing non-oriented silicon steel was studied, and high-performance non-oriented silicon steel with high strength and low iron loss was prepared. The results revealed high-density nano-B2 Cu-rich precipitates in the annealed sheets. With increased annealing temperature, the size of the precipitates gradually increases at first, followed by a significant increase, while the number density and volume percent of the precipitates initially decrease significantly and then decrease slowly. Under the pinning action of nano-B2 Cu-rich precipitates, the grain grows remarkably first and then slowly. The precipitation strengthening contribution of the nano-B2 Cu-rich precipitates decreases first and then increases, and the grain boundary strengthening contribution is gradually lowered. Under the influence of both, the strength of the silicon steel decreases first and then increases. Due to the low mismatch between the nano-B2 Cu-rich precipitate and the matrix, the precipitates do not deteriorate the iron loss of Cu-containing silicon steels,and the increase in grain size reduces the iron loss,which significantly decreases first and then increases slowly.When annealed at 950-1 000 ℃, the size and density of the nano-B2 Cu-rich precipitate are optimal, which can improve the yield strength by more than 200 MPa without deteriorating the iron loss. Therefore, the synergistic optimization of high strength and low iron loss of non-oriented silicon steel can be achieved.
景文强, 程朝阳, 倪正轩, 钟柏林, 刘静. 退火温度对含铜高强无取向硅钢强度和铁损的影响[J]. 钢铁, 2023, 58(3): 119-127.
JING Wen-qiang, CHENG Zhao-yang, NI Zheng-xuan, ZHONG Bo-lin, LIU Jing. Effect of annealing temperature on strength and iron loss of Cu-containing high-strength non-oriented silicon steel[J]. Iron and Steel, 2023, 58(3): 119-127.
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