关键词: 无缝钢管连轧, 限动芯棒, 有限元分析, 金属流动, 工艺优化

Abstract: A steel pipe continuous rolling process simulation model of a 180 mm retained mandrel pipe mill was established. The model was simulated to show the distributions of stress, strain and displacement on the cross-sections of steel pipes and the evolutions of wall thicknesses and diameters during the rolling processes of retained mandrel pipe mills. This model was designed to reveal the rolling pressure distributions, variations of the total rolling forces, the effects of temperature and the friction coefficient in the rolling zones on wall thicknesses and rolling forces. The wall thickness and diameter data of the steel pipes were extracted from the simulation results by cubic spline interpolation method. The finite element model was validated by the measured rolling force and wall thickness data of the industrial productions of the target units. It is found by simulation that during the continuous rolling processes, the steel pipes firstly reduced the diameter in the longitudinal direction, and then the wall thickness deformations occurred. In the lateral direction, the metal mainly flows from the top areas to the open areas. The contact pressures of the first three mill stands mainly concentrate on the top areas with large amount of deformations, which is the main deformation mill stand. The contact pressures of the fourth and fifth mill stands are the largest in the side areas with small amount of deformations, which mainly plays the role of finishing and rounding. With the rolling temperature increases, the wall thickness of steel pipes increases and the rolling forces decrease. With the friction coefficient between the mandrel and the steel pipe increases, the wall thickness decreases and the rolling force decreases. The simulation results support the key structural design of the rolling mills, the determination of rolling process parameters and the optimization of process parameters in engineering commissioning.

Key words: continuous rolling of seamless steel pipe； retained mandrel； fimite element analysis； metal flow, process optimization