【作者】 赵石岩；

【导师】 郭宝峰； 金淼；

【作者基本信息】 燕山大学 ， 材料加工工程， 2009， 博士

【摘要】 UOE焊管成形质量控制的最终目的是使板料经过多步工序成形焊管的椭圆度和桃形凸度达到精度要求。UOE工艺涵盖了对宽厚板依次进行的板边弯曲、U成形、O成形和扩径等成形工序,是一种多工序集成的成形过程。各种工艺参数之间的相互影响关系复杂,而其又直接和焊管的成形质量相关。因此,对UOE成形工艺过程进行控制,使板料在各阶段的变形协调以提高最终制品的质量具有重要意义。本文首先对UOE工艺进行理论研究。基于板料在成形过程中的变形特点,推导了弯边、U成形和O成形工序的成形力和模具行程计算公式,并给出了板料在各成形阶段的回弹预测表达式。建立了UOE工艺过程的连续仿真有限元模型,并揭示了板料在成形过程中的变形机理。板料的变形包括弯曲、反弯曲、压缩和拉伸。弯边和U成形阶段以板料的弯曲变形为主;O成形阶段以板料局部反向弯曲和周向压缩变形为主;扩径阶段以周向伸长和壁厚减薄为主。沿圆周方向,坯料内部存在两个残余应力较大的区域,一处是U形弯曲件直壁段与圆弧部分过渡区,另一处是直壁段最先产生弯曲变形区域。UOE焊管成形过程属于多变量、强耦合的复杂弹塑性变形过程,很难得到工艺参数与最终制品质量的简单映射关系。本文以最终制品的椭圆度和桃形凸度为控制对象,根据后续工序成形质量要求确定前一步工序应该控制的质量参数,制定UOE成形工艺的质量控制参数及指标体系。通过对各质量评价指标对成形质量的影响定性和定量分析,制定了UOE焊管成形质量的控制策略。结合构建的质量评价体系,通过对MARC软件进行二次开发,建立了集成可视化菜单模块、UOE工艺过程仿真参数化建模模块、质量评价指标自动生成模块、人机交互式仿真计算模块以及缺陷分析模块于一体的UOE成形工艺过程仿真系统。仿真系统可在给定的工艺参数下,实现对焊管UOE工艺过程的正向仿真,模拟板料在成形工序中的连续变形过程,也可实现有继承的单工序仿真计算,并可自动输出成形载荷、回弹变形、制件尺寸、形状误差、残余应力分布等信息,为UOE工艺成形焊管过程的工序评价和分析提供便利。基于该系统的研究成果已应用于宝钢新建UOE大直径管线钢管生产线项目。通过成形工艺实验研究,测定了O成形载荷和制品椭圆度、桃形凸度。实验结果和理论分析、数值模拟结果吻合较好。更多还原

【Abstract】 The goal of quality control of the UOE forming process is that ellipticity and convex amount of pipe reach given precision. The process of UOE is integrated multi-operation, which contains edge bending, U-forming, O-forming and expanding. Technological parameters which have something with the quality of pipe impact on each other. It is important to control the forming process of UOE to improve the final product quanlity by compatibility of deformation in each stage.The fundamental theory of the forming process of UOE was studied in this paper. The formulae for calculating forming force and dies stroke of edge bending, U-forming and O-forming was deduced, and the predictive expression of spring-back was given in each working procedure.The FEM model for continuous simulation of UOE process was built, and deformation mechanism of sheet metal during the forming process were disclosed. The deformation of sheet metal contains bending, reverse bending, compress and tension. Bending is the main deforming in edge bending and U-forming; Local reverse bending and circumferential compress are main deforming in O-forming; Circumferential elongation and wall thickness reduction in expanding. The section have two regions whose residual stress is rather large, the intermediate zone of the arc parts and straight-wall section and the domain of straight-wall section where bending happened firstly in U-forming.It is hard to get a simple mapping relationship between technological parameters and the final product quanlity, as UOE process belongs to multivariate and close coupling elastic-plastic deformation. The quality control parameters and index system were established in this paper through determining the supposed quanlity control parameters of the stage by the forward one, which was made by controling ellipticity and convex amount of pipe. The qualitative and quantitative analysis of quality evaluation indicators influence on the quality of pipe is conducted and the quality control strategy of UOE pipe processing is proposed. According to the quality evaluation system, a virtual simulation system has been developed to simulate the forming process of sub-merged arc welded tube with large diameter using UOE method. The system is a secondary development of MSC.Marc which consists of visual menu, automatic generation of parametric model, automatic generation of quality evaluation indicators, numerical simulation with man-computer interaction and forming defect analysis modules. Once required technological parameters is given, with the aid of the module of automatic generation of FEM model, what is needed is only several simple operations to establish planar or 3-D FEM model, then the forming processes of steel plate from edge bending till expanding continuously. It also allows user to conduct subsequent simulation from the step where is a revision of the technological parameters is made according to the results of the forgoing simulation steps. After the simulation, important data on load, spring-back, size of product, shape tolerance and distribution of residual stress of product are provided automatically by the system. This system provides user with a convenient platform for UOE process simulation and analysis. The findings and simulation system have been applied to the new project of producing pipe line with large diameter in Baosteel.The ellipticity, convex amount and forming force of O-forming were measured in the experimental study. The experiments results are in good accordance with theoretical analysis and numerical simulation.更多还原