Abstract: Described in the paper are the main aspects of the Φ159 mm FQM 3-roll Mandrel Pipe Mill located in Pangang Group Chengdu Iron & Steel Co., Ltd., including the process, and the composition, features and basic data of the main equipment units. With the three-roll structure, satisfactorily-enclosed pass is available which ensures more homogeneous metal deformation, significantly-improved wall thickness and OD accuracies and better surface finish of the shell. Thanks to the three-roll formed pass, the contact area is reduced, and thus the rolling pressure is also reduced, which lessens the overfill or under-fill of the pass so as to enhance the ability of the mill to roll light-wall tubes and hi-deformation steel grades. Furthermore, with the well-enclosed pass, defects like tube-end folding or fin is eliminated or reduced, and the pre-stretch-reducing cropping length of the tube is shortened or even the cropping process can be eliminated at all, resulting in higher yield and better rolling consistency.