Feng Chien-Cheng, Lin Ming-Hong, Chuang Wei-Heng, Chen Yi-Cheng, Ou Shih-Fu
Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, No. 415, Jiangong Rd., Sanmin Dist., Kaohsiung 80778, Taiwan.
Department of Mold and Die Engineering, National Kaohsiung University of Science and Technology, No. 415, Jiangong Rd., Sanmin Dist., Kaohsiung 80778, Taiwan.
Materials (Basel). 2022 Feb 18;15(4):1534. doi: 10.3390/ma15041534.
Poor formability in hot-rolled strips may be attributed to the many pearlite-banded structures (PBSs) that develop in steel during the hot-rolling process. The challenge of manufacturing strips with minimum PBSs is that multiple factors influence the amount and distribution of the PBSs. This study used the Taguchi method to find the optimum hot-rolling parameters to obtain strips with a reduced number of PBSs. The strips were then subjected to bending tests to evaluate their ductility. The first part analyzes the contribution of selected parameters to the hot-rolling process: (1) finishing rolling temperature, (2) finishing rolling speed, (3) coiling temperature, and (4) coiling speed. The second part confirms, using bending tests, the influence of the finishing rolling temperatures 780, 800, 820, 840, 860, 870, and 880 °C on the formability of an A36 hot-rolled strip. Based on the experimental protocol for the study, the optimal process parameters were determined to be the finishing rolling speed (0.80 m/s), finishing rolling temperature (870 °C), coiling speed (2.80 m/s), and coiling temperature (650 °C). When the A36 strip was prepared at the optimum parameters, the average length and thickness of the PBS were 108.61 ± 0.11 μm and 10.18 ± 0.12 μm, respectively. According to the Taguchi analysis, the finishing rolling temperature had the most significant influence on the dimensions of the PBS. In tests where the hot-rolled A36 strip was bent to 90° and 180°, at the finishing rolling temperatures of 870 °C and 880 °C, no cracking was observed at the R angle.
热轧带钢的可成型性差可能归因于热轧过程中钢中形成的许多珠光体带状组织（PBSs）。制造具有最小PBSs的带钢面临的挑战在于，多个因素会影响PBSs的数量和分布。本研究采用田口方法来寻找最佳热轧参数，以获得具有较少PBSs数量的带钢。然后对这些带钢进行弯曲试验，以评估其延展性。第一部分分析选定参数对热轧过程的贡献：（1）精轧温度，（2）精轧速度，（3）卷取温度，以及（4）卷取速度。第二部分通过弯曲试验，确认了780、800、820、840、860、870和880℃的精轧温度对A36热轧带钢可成型性的影响。根据该研究的实验方案，确定最佳工艺参数为精轧速度（0.80米/秒）、精轧温度（870℃）、卷取速度（2.80米/秒）和卷取温度（650℃）。当以最佳参数制备A36带钢时，PBS的平均长度和厚度分别为108.61±0.11μm和10.18±0.12μm。根据田口分析，精轧温度对PBS的尺寸影响最为显著。在热轧A36带钢弯曲至90°和180°的试验中，在870℃和880℃的精轧温度下，R角处未观察到裂纹。
