Research On Technics Controlling Roll And Cooling Of 70# Excellent Carbon Steel Dish Winding

Based on the successful experience of adopting rolling and cooling control process into high speed rod coil bar hot rolling production, through the researching and discussing on the parameters of heating temperature, heating time, Austenite re-crystal zone rolling process, Austenite non-re-crystal zone rolling process, temperature at start point and fine rolling period, cooling speed, etc of high quality steel coil bar, the result that could guiding production is concluded. This result proved that: Reasonably controlling the cleanness and chemical content is the precondition to get No. 70 high quality carbon steel line coil bar; The temperature before first rolling should be controlled below 1060～1080℃,the Austenite grain getting before phase transformation is smaller; Rolling in the Austenite non-recrystal zone,the Sorbite structure begree is smaller than in the Austenite recystal zone; Cooling speed of 10～18m/s could acquire 1.5～2.5 level Sorbitie structure. In this article, the improvement to cooling process after rolling and suitable rolling and cooling process for No. 70 high quality carbon steel line hot rolling coil bar is introduced.After several years of application, rolling and cooling control process has been used in Chongqing Iron & Steel company high speed plant having produced more than one hundred thousand tons of No. 70 high quality carbon steel line coil bar with its mechanical performance 100% qualified. Therefore, this process could take in place of original production process.