Control Technique of Break Marks in Hot Strip Mill
LI Jun1,2
1.Material Department, Panzhihua Iron and Steel Research Institute，Panzhihua 617000, Sichuan, China; 2.Faculty of Materials and Metallurgical Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China
Abstract：Based on spike height resulting in break marks, the new technique of eliminating break marks by getting microstructure of quasiacicular ferrite in hot strip mill was applied. The results show as follows: （a）There is a critical spike height for producing break marks. By getting microstructure of quasiacicular ferrite, spike height can be decreased below the critical point and it is more important to reduce remarkably the difficulty of controlling break marks; （b）Factors such as higher carbon content, coarser austenite grain, faster accelerated cooled rate, lower accelerated cooled start/end temperature can promote the formation of microstructure of quasiacicular ferrite, and the optimal accelerated cooled start/end temperature are at which proeutectoid ferrite and pearlite start to form respectively. The new technique has been applied successfully at PZH Steel.
2009, Vol. 44 
