Parametric Design And Database Establishment Of Supporting Mandrel In The Elbow Hot-bending Process

With the rapid development of industry,pipeline system is widely used in various industries and fields.As an important part of the pipeline system,elbow is widely used in aerospace,shipbuilding,electric power,automobile industry and petrochemical industry.Since the reform and opening up,a large number of researchers in China have studied the various forming methods of elbow,especially the large number of researches on the hot forming of elbow.Through unceasingly in the practical production test and summary,the researchers found that in elbow and pipe between a reasonable hole enlargement ratio range,when according to the reasonable scope of hole enlargement ratio to design and choose of rods,can very good push to produce good quality of elbow.However,due to the limitations of the size specification of the tube billet,the former design staff can only have individual cores designed according to the reasonable expansion ratio when designing the core bar.In recent years,with the development of the tube billet production technology,the tube billet elbow in the actual production to choose the specification more and more,mandrel designers are no longer as before design according to the existing pipe mandrel,but according to the reasonable scope of hole enlargement ratio design good mandrel and then to choose the pipe,it is helpful to realize the standardization of the mandrel design.At the same time,it is also helpful to realize the parametric design of mandrel.In this paper,taking the elbow of Φ57 × 3.5 × 76 as an example,modeling the horn core rod by using the 3D modeling software UG,and designing the coil of induction heating.The model,material model,unit type,contact model,friction model and pushing speed of the finite element model are selected and set in the preprocessor of Deform software.Using Deform to bend the heating process in the process of production of the pipe and the temperature field in finite element analysis,get the tube billet temperature field distribution in the whole process of hot push and tube billet temperature curve of change over time.Then,the numerical simulation of the bending process is carried out,and the wall thickness and equivalent strain are analyzed.At the same time,the influence of the center line of the core and the Angle of the horizontal line α,The short axis and long axis ratio k of the mandrel section ellipse,the velocity and the friction coefficient on the forming quality of the elbow is studied and analyzed.In this paper,on the basis of forefathers’ research,this paper gives a general design method of horn mandrel.Then,based on UG’s parameterized modeling of the mandrel,a second development is carried out to realize the parameterized modeling of the core rod in the 3d modeling software UG,which only needs to input the basic parameters of elbow and tube billet.And set up the horn mandrel library,the commonly used core rod into the horn mandrel and implementation in the horn mandrel machining can be directly called directly from horn mandrel libraries core data,avoid the mandrel many design and a lot of repairing mold such as man-made factors on the quality of the bend forming.