.304 L Stainless Steel Heat Deformation Process Of Microstructure Evolution Mechanism

304L austenitic stainless steel is one of the main materials of heavyforgings. The nuclear power stainless steel heavy forging not only volume are big, but moreover the request material must be pure and the forging structure property is even . The temperature which, the material streamline and the distortion no uniformity causes by the free forging cause in the forging process in the heavy forging actual production to have the hot forging dehiscence, the crystal grain thick and non-uniform and so on difficulty technical questions. Solves the above question key to lie in the forging interior grain refining and even, its technology's core is forges in the process the heavy forging interior crystal grain size active control. However, the investigations of essential character in China far lagbehind practical manufacture, furthermore, the further optimization of hotworking process were firmly retarded.In this article, uses the Gleeble-1500D thermal / mechanical simulation testing machine do single-stroke hot compression tests to the forged 304L austenite stainless steel under different deformation temperature , the different deformation strain rate, obtained the strain-stress curves of 304L austenite stainless steel, studied the influence of deformation conditions such as initial grainsize ,deformation temperature, deformation amount, quantity and strain rateto austenite recrystallization behaviors and flow-stress curves. build dynamics model, kinematics model,flow stress model, recrystallization grain size model and the dislocation density model. We have obtained the recrystallization grain size,configuration and distribution of dislocation by analysis the results of metallographic experiment and transmission electron microscopy (TEM) experimental.Using ANSYS finite element thermal simulation software to simulate the deformation process, analysis the equivalent strain, stress and temperature distribution in differen deformation zone of 304L stainless steel samples during hot deformation. The effect of uneven distribution of strain during compression on dynamic recrystallization and grain size of austenite was analyzed with reference to metallurgical map .The results show that in different regions of the specimen, equivalent strain and stress distribution varied widely; temperature was also different;The effect on dynamic recrystallizatio of the shear strain is large than the equivalent strain; under the maximum deformation of the test ,there is a critical value of the effect on grain refinement of equivalent strain,but with the increase of shear strain, austenite grain continue to refine with the increase of shear strain, so,can be seen, the effect of the shear strain on austenite grain size is greate than equivalent strain.The simulation results with the experimental results, indicating that the model can be used to accurately describe the process of hot deformation of 304L stainless steelThrough the thermal simulation experiments and numerical simulations to explore the grain size, distribution, causes and due to micro-mechanism under hot deformation and establishes the microscopic crystal grain size and the distribution rule and the amount of deformity, the distortion temperature, the soaking time, the stress condition and so on between the macroscopic deformation coordinates relations.The research results may provide the reliable scientific basis for the nuclear power austenite stainless steel heavy forging production in plastic processing quality forecast and the control technology.