The technique of precision plastic
deformation can improve product quality, properties and their market competitive ability.
Not only it can save material and power, shorten manufacturing period and decrease production costs, it can also obtain complex structure and good surface quality of forming part. The technique of precision plastic formation tend to complication, precision, optimization quality ,
simulation of technological design and the integrity of CAD and CAM in die design and manufacture.The law of plastic
deformation was known by means of photo-plasticity simulation. Deformation information in deformed body can be obtained some results were gotten with the aid of photo-plasticity simulation of no-flash die forging star-like inner race. The deformation of metal material is symmetrical in the technique of no-flash die forging star-like inner race. Strain state is changeable in deformation region. Deformation region is divided into rigidity, even deformation and violent deformation region. The area under the punch is rigidity region. The area of part center is the even deformation region. The other region is violent deformation region. These results of simulation experiment play an important role in die design of no-flash die forging forming star-like inner race of steel.