Investigation On Partible-die Forging Technology For The Elbow And Triple Valve

Pipe joint is an important connector in piping system. Due to its wide usage inpetroleum, chemical, nuclear and aerospace and other industries and severe itsperformance demanding, it is necessary to employ forging process to form pipe jointforgings. At present, the forged pipe joint is formed into solid forging firstly bycommon hot die forging, loose tooling forging or free forging and then followed bythe machining to obtain the inner hole and the dimension of the shape. However, theprocess above would produce large quantities of metal chips as waste inevitably andeven worse make the flow lines become discontinuous, thus degrading mechanicalproperties obviously. Moreover, this process would face other challenges such as highenergy and seriously environmental pollution, which is unable to meet the currentrequirements of energy saving and low carbon manufacturing. Partible-die forgingtechnology, especially for multi-way forging which is a typical process of partible-dieforging, is quit suitable for complex products with holes and it can achieve the closestsize with real forgings, thus realizing near net shape technique. Therefore, partible-dieforging technology is very fit for forming the parts such as pipe joint.In this paper, the coupled thermo-mechanical model of the partible-die forgedelbow is established based on the finite element method. Based on this method, theevolution laws of metal flowing and mechanics parameters, and the distribution lawsof strain and temperature are thoroughly revealed. Also, the effects of the workpiecedimensions, the feeding speed of the main punch, the initial temperature of theworkpiece and the friction factor on the effective strain, temperature and mechanicsparameters, and the influence law of different loading schemes of the punches on themetal flowing, effective strain and mechanics parameters are systematicallyinvestigated. Furthermore, the coupled thermo-mechanical model of the multi-wayforged equal triple valve is also established based on the finite element method. Byusing this method, the evolution laws that the effects of different loading schemes ofthe punches on the metal flowing, effective strain, temperature and mechanicsparameters. On the basis of finite element method, the technological test schemes ofthe partible-die forged elbow and the multi-way forged equal triple valve are designed by the common forging equipment, which verifies the accuracy of finite elementsimulation and obtains the qualified forgings.Through the analysis and investigation above, the results can not only providetheoretical and technical support for the research and extension of the partible-dieforged elbow and the multi-way forged equal triple valve processes, but also providethe important foundation and basis for technical improvement and practicalgeneralization of the partible-die forging process.