Third Roll Tube Technology And The Impact Of Technology On The Quality Steel

Hengyang Steel Tube (Group )Co.,Ltd has the only set of full three-Rolling Mill in the world - The 0108mm Three-Rolling Mill, which adopts the unique craftsmanship of three- roll piercing - three -roll rolling - three roll SRM with the designed capacity of 30,000 tons. It has not actually reached a capacity of 66,000 tons until its technical innovation. During recent years, the previous production process and equipments can not meet the market due to customer's more and more critical quality requirements on tubes especially those on tube's surface quality. In order to solve surface quality problem, the author of the thesis, together with his collegues, has conducted many experiments and tests for more than one year and finally detected the causes for defects like cracks or crack lines on the surface, We have explored out the optimal production process route, and fixed the most efficient items for technological transformations. By analyzing the reasons of formation of cracks or crack lines on the tube surface and by analyzing the different influences of different piercing processes on surface quality , the model for the optimal production process route was put forward. By analyzing the formation characteristics of the piercing Mill, together with considering the varieties and sizes of this Mill, the designed models of the piercing roll, plug, guidance board, and roll knurl were suggested, which optimized the three roll rolling process ,established the experienced formula of feeding angle of the three roll rolling mill. The SRM ellipticity equation was presented in the thesis.In the following technological transformations finished year, the