根据PQF连轧孔型及工艺特点，分析了连轧管宽展规律对产品尺寸精度和钢管横截面积的影响，并建立PQF连轧过程三维非线性有限元模型，预报了荒管的尺寸形状，对比某厂现场数据，两者吻合良好。通过对不同孔型、不同规格产品的系列仿真，研究宽展规律的影响因素，分析了延伸系数和空隙率对周长系数的影响，延伸系数和减径率对壁厚系数的影响；并利用多元线性回归分析法得到PQF连轧宽展模型，为PQF连轧孔型设计及产品尺寸精度控制提供了理论指导。

According to the geometric pass and technological characteristics in the three-roll continuous mandrel rolling process, the effects of spread rule on the tube dimension accuracy and cross sectional area of tube was also investigated. A 3-D nonlinear finite element model of this process was established to predict the size of elongated shell. The simulation solutions show good agreement with the experiment results. By a series of simulations on different pass and different specifications, the influence factors of spread rule were studied including the effect of the lengthening coefficient and the clearance rate on the circumference coefficient and the effect of the lengthening coefficient and the reducing rate on the thickness coefficient. The spread model was also obtained by multiple linear regression analysis method which provides a theoretical basis for the pass design and the tube dimension precision of the three-roll continuous mandrel rolling process.