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For the head single piece, small batch production tooling costs, the problem of high cost of production, this paper presents a new technology to an overall pressure bulging head. In this paper, a combination of experimental and numerical simulation methods, bulging of internal pressure on the head as a whole. First of all, the force of pressure inside the head as a whole bulging process, need to come to a head as a whole pressure bulging critical pressure formula. Then, the initial sheet size φ360 × 3mm in two different geometric shapes Q235 specimen hydraulic bulging experiment, round flat state specimen cracking in the bulging process, whereas the blanks were pre-bend specimen in loaded to 7MPa uninstall the ratio of the length of the shaft 2.6 elliptical head, a small gap between standard elliptical head (the ratio of the length of the shaft 2). The basic data of the internal pressure in the head as a whole bulging obtained through experiments to determine the feasibility of the inner pressure in the head as a whole bulging. Based on the above experiment, the finite element simulation of the pressure inside the head as a whole bulging, and the simulation results are compared with the experimental results, the pressure bulging process of stress concentration and effect analysis of the specimen, including force size and distribution of the initial geometry of the specimen has a great influence on the bulging results. Specimen welds to the bulging process the weak point, round flat state as a whole internal pressure bulging head, specimen weld stress concentration the serious large plastic strain of the material, when the internal pressure 3MPa weld The stress of 507MPa, effects such as variable up to 42.5%, resulting in cracking of the specimen; the specimen can greatly reduce the stress concentration in the bulging of the initial sheet preflex, pre-bend specimens, including pressure 7MPa The weld stress 460.8MPa, equivalent stress becomes 10.5%, 24.7% of the maximum equivalent strain 3MPa when only round flat state specimens, including pressure. Through comparison of experimental and finite element simulation study specimens pre bend radius to take the rough radius of 1/9 more appropriate specimen bulging can effectively reduce the stress, strain, and so on. Inflation pressure on the head as a whole shaped the course of stress and strain fields and bulging after specimen geometry, reveals the head bulging pressure within the whole law, and the overall head pressure bulging rough structure and process optimization. On this basis Q235, φ3600 × 30mm head finite element simulation of the whole internal pressure bulging. Simulation results show that the internal pressure of 10MPa, the ratio of the length of the specimen axis was 1.89, less than the standard elliptical head of the length of the shaft 2; weld specimen equivalent strain largest, at 12.9%, less than the limit of the material extension rate of 27%; the top of the specimen material thinning rate of 7.7%, less than 13% of the prescribed rate of thinning GBT4746-2002 local strain and local thinning does not occur in the form of process pressure within the head as a whole inflation The phenomenon, which demonstrates the feasibility of the inner pressure in the head as a whole bulging.
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