Discussion on Hot-rolling Process of Seamless Steel Tube with 20CrMoNbVTiB Continuous Casting Round Billet

Addressing the problems as staying with the 20CrMoNbVTiB CC billet in Steel Grade 110S such as poor plasticity,high resistance against deformation during rolling process and a lot of difficulties as occurring in the rolling operation,the technological process of the Φ180 mm mandrel pipe mill is discussed and optimized,involving a number of measures,including increasing the circular furnace temperature,lowering the rpm of the piercer,adapting large feeding angle,using after running-in roll,adjusting MPM rpm,and re-heating the shell in the MF furnace prior to sizing process,etc. Thanks to the above mentioned optimization of the mill,the whole hot-rolling process is performed very well.Moreover the plug service life is greatly prolonged,the repair rate is remarkably reduced,and the yield is enhanced from 81.6% up to 91.5%.