中文摘要：

鉴于大型直缝焊管的几何特殊性，多采用压力矫直的方式修正其直线度。受材料批次、热处理、变形情况等因素的影响，焊管的性能参数会有较大波动，准确地识别出管件的材料性能参数是提高矫直精度的一个重要条件。采用有限元方法验证了相同截面形状、相同材质的小曲率曲管在压力矫直过程与直管三点弯曲过程的等价关系；依据直管三点弯曲过程的理论模型建立了在线识别材料性能参数的识别系统，只需输入管件的几何参数、矫直模具参数、载荷行程实验数据，即可获取管件的真实材料性能参数。大型管件的有限元仿真结果和小尺寸管坯的试验结果均验证了识别系统的可行性、可靠性。

英文摘要：

According to the geometric particularity of longitudinally submerged arc welding （LSAW）pipes,at present a pressure straightening method inclined to be applied by the manufacturers to correct their straightness.Accurate identification of the material parameters of pipes is an important conditions for improving straightening precision of the material parameters which always have large fluctuations by the influences of the material batch,heat treatment and the deformation history.The e-quivalence relation between the small curvature pipe in pressure straightening process and the straight pipe in three-point bending process was verified by finite element method firstly.Then an on-line iden-tification system of the material parameters was establish based on the theoretical model of straight pipe in three-point bending.Finally,the material parameters of the pipes can be obtained by inputting the values of the pipes＆#39;geometric parameters,straightening moulds parameters and load-stroke exper-imental data to the system.The feasibility and the reliability of the identification system were verified by the FEM simulation of large pipes and the physical simulation experiments of small pipes.