Abstract: Based on the previous simulation experiment,the inner support ring of the nozzle with large taper was obtained by multi-fire forging,and the grain size was analyzed to judge the performance of the forging.According to the simulation,the forging forming process is well coated,and the size meets the design requirements.From the actual forging point of view,the forging has no cracks and pits and other defects after many forging forms,and the forging also meets the size conditions;The change of grain size before and after forging is obvious,and the whole grain size is more uniform and obviously refined after rolling,about 4.5～5 grade grain of 60%and the 9.5～10 grade fine crystal of 40%.The grain of big end size compared with the small end after forming,and the big end is finer.The whole section of the grain size is uniform after heat treatment,reaching 6.5～7 grade.