The commercial pilot production for 693 pieces of 168 mm x 7 mm tube rolled by Accu-Roll mill from 192. 39 t Φ180 mm round casting bloom of steel B grade (0. 20% C) with center line shrinkage rating W2 has been carried out. Results show that the yield of rolled tube is 90% ； there are not defects in internal surface of tube such as internal overlap

abscess layer and cracks； the tube isn't leaking water by water pressure test with 15 MPa for 5 s and each tube is passed and qualified by ultrasonic examination according to standard GB/T5777-1996 with artificial defect depth rating C12. 5.