Research and application of hot rolling coiling process for 600 MPa high strength steel
ZHANG Liang-liang1,2, YU Yang1,2, LI Xiao-jun3, SHI Zhen3
1. Jingtang Technology Center, Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China; 2. Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production Technology, Beijing 100043, China; 3. Manufacturing Department, Shougang Jingtang United Iron and Steel Co., Ltd., Tangshan 063210, Hebei, China
Abstract：In order to explore the change law of iron oxide scale, microstructure and property of hot rolled strip during coiling, the scanning electron microscope, electron probe, optical microscope, transmission electron microscope and tensile testing machine were used to study the effects of different coiling temperatures and cooling methods on the surface quality and microstructure properties of 600 MPa hot rolled strip. The results show that at the coiling temperature of 650 and 600 ℃, compared with the slow cooling method, the rapid cooling method can effectively improve the structure of iron oxide scale on the surface of hot rolled strip, increase the proportion of FeO in the iron oxide scale by 10%-15%, and decrease the thickness of iron scale by 25%-30%. At the same time, it can effectively weaken the enrichment of silicon and manganese elements at the interface between the iron oxide scale on the surface of hot rolled strip and matrix. The grain size in the hot rolled strip under different cooling processes is similar. The yield strength of hot rolled strip under the process of 650 ℃ coiling + rapid cooling is the highest, and the dislocation density at the fracture of sample is the highest, but the elongation after fracture does not decrease significantly.
张亮亮, 于洋, 李晓军, 史震. 600 MPa级高强钢热轧卷取工艺研究及应用[J]. 中国冶金, 2022, 32(12): 106-112.
ZHANG Liang-liang, YU Yang, LI Xiao-jun, SHI Zhen. Research and application of hot rolling coiling process for 600 MPa high strength steel[J]. China Metallurgy, 2022, 32(12): 106-112.
2022, Vol. 32 
