Large With Flange Head Forging A Numerical Simulation Study

With the development of economy in our society, the pressure containers in some industries, such as nuclear power, coal, oil refining and petrochemical industry, present a development trend of large-scale. Especially large diameter and wall thickness of hydrogenation reactor, coal liquefaction etc, put forward a new topic to the reactor manufacturing industry. Head is mainly confined part of pressure vessel. Not only the size is increasingly large, but also the shape is complex day and day. The large head with flange which used in hydrogenation reaction is a typical case. This kind of large head with flange has five meters above in outer diameter, and 0.175 meters in wall thickness. Its whole forging brings higher requirements on large forging equipment and technology.In this paper, to research the possibility and feasibility of its shape, an initial head's forming scheme proposed by a domestic company has been simulated. The changing laws of head's wall thickness and rotation pressing height during deformation process have been analyzed also. It shows an uneven reducing speed of wall thickness on rotation pressing. The most intensive reducing is located near the round angle of the lower die and a necking phenomenon may even appear in this field, but the rotation pressing height would decrease and then arise. The simulation results show that there are many problems existed in the initial process scheme. For example, short blank; one process upsetting can not achieve the initial scheme requirements because of limited forging capacity of forging equipment; uneven wall thickness and necking phenomenon during rotation pressing; the flange is not obvious, and the root of flange exists serious shortage of meat after final forging, etc.To solute the problems existed in the initial process scheme, after large number of numerical simulations, this paper optimizes billet size and the mass increases to 197.2t. After that, the degree of uneven wall thickness and necking phenomenon has been change observably. By optimizing half-moon anvil shape and mold forming process, the flange after forming reaches the standard part. Process scheme has been changed so to cut the process out. Finally it puts forward the most optimization process scheme which could form the reasonable head and the head would meet the requirement through the simulation. Analysis shows that, the forming head by eventually forming process scheme is consistent with the forgings in shape. The quality is good, and the forming process is simple and feasible, etc. It has good reference value to the forging of actual production factory.