Optimized forming process for improving forming quality of outer transition sleeve

Based on the stress status in load transfer zone during radial close-in process,the structural shortage of close-in die and the resilience of base material,the root cause for the diameter deviation of outer transition sleeve of gas turbine combustor was analyzed.It was testified that the close-in process was not suitable to form this kind of sleeve parts.Therefore,the bulging process was discussed to replace the original close-in process,which expanded the overall sleeve part by the action of the tensile stress and thus solving the problem of wall thickening in the deformation zone and the buckling in load transfer zone etc.A new rigid bulging die with conical sliding blocks was designed and the profile size of each block was eventually defined through forming tests.The final inspection results show that the material resilience after bulging process is controlled technologically and the quality of sleeve parts is significantly improved to meet the designed requirements.