Process Of Hollow Ingot Forging

Large cylinder forgings are the key components of nuclear power,petrochemical, thermal power, coal chemical industry, aeronautics andaerospace pressure vessel. At present, the large cylinder forgingsmanufacturing mainly use the ordinary solid steel ingot in domestic, themanufacturing process is: chamfering blanking pressure jaw-rough upsettingremoval of water riser-upsetting punching-core bar stretching-saddleforging-precision forging. Using this method manufacturing large cylinderforgings, more process number, more heating number, more internalorganization defects, the forming quality is n’t easy to control, external sizeallowance is large, the utilization rate of steel ingot is low, cannot satisfy thefuture requirements about green, environmental protection, low carbon,emission reduction. Using hollow ingot manufacturing large cylinder forgingshas incomparable advantages of material saving, energy saving and shortprocess compared with the solid steel ingot. The application of hollow ingot isan important way to solve the large cylinder forgings green manufacturing andproduct large-scale trend.This dissertation first carry on the system research of hollow ingotupsetting through numerical simulation and experiment, theoretical analysis,provides the relationship between hollow ingot upsetting and the shape ofhollow ingot, the hollow ingot upsetting scope of application and permissionreduction are preliminarily obtained.Through numerical simulation, the deformation effect and influence lawof upsetting, core bar stretching and saddle forging on the process of hollowingot’s spherical, radial, axial and tangential cavity defect closure werestudied, the upsetting experimental verification for radial and axial cavitydefect closure has also done. The research shows that the hollow steel ingotblocking process could not choose upsetting, directly conduct core barstretching or saddle forging.Finally through numerical simulation and production experience, the reasonable process parameters of core bar stretching and saddle forging areobtained, and numerical simulation of using hollow ingot manufacturing largecylinder forgings through two different process combinations: directly corebar stretching-saddle forging, cogging by saddle forging-repeated upsettingand stretching-saddle forging, the repeated upsetting and stretchingnumerical simulation process make full use of hollow ingot upsetting theorythe above has been obtained, upsetting and stretching process have very goodcohesion. Through the simulation research of the two different processes, theeffect of composite load on forging forming is preliminary concluded.The research work in this dissertation provides useful references for theuse of hollow ingot manufacturing cylinder forgings, and also provides thebasis for back-stepping hollow ingot ingot model by forging.