Improvement and Process Experiment Research on Production Line of Ultra-fine Grain Screw-Thread Steel

For reducing consumption of energy without increasing cost of production,improving comprehensive properties,according to the equipment and technical renovation fund condition in Jinan iron and steel Ltd production line,the first step is innovation of middle or finishing mill,cooling and control systems,etc.Then,Ⅱ level and Ⅲ level reinforced bar is produced at lower cost and higher added value through transformation strengthening and fine grain strengthening using average carbon manganese steel with little or without microalloy element.After the second step innovation,such as rough mill reform,Ⅲ level and Ⅳ level reinforced bar is made when the production process is organized according to the technology of ultra-fine grain technology.