Nuclear Power Binglei Forgings Finite Element Analysis And Experimental Study

Generally, the free forging has little flaw, but in terms of heavy forging, the chance of appearing flaw is much higher, therefore it is necessary to predict such flaws in free-forging process by using CAE simulation, thus to avoid huge economic losses.Based on vessel head project of China Erzhong, this paper has focused attention to research the blank-forming process in order to decrease cracks in vessel head during the following process of drawing and punching so as to obtain a relatively high quality. Meanwhile, because the upsetting deformation is the main forming mode for heavy disk forgings, the reject rate is high and a large-area of dense defects in forgings'central area is the main quality issue when processing ultrasonic flaw detection.Both material characteristics and mechanical conditions result in the flaw appearing in central area of heavy disk forgings used for nuclear power station. Based on rigid-plastic model in FEM software DEFORM, this paper, taking the model provided by China Erzhong as study object, has combined methods of numerical simulation and theory analysis, firstly carries on numerical simulation and the finite element analysis to the cylinder upsetting between platens; then secondly makes simulation to the upsetting between cone platens; finally, analyzes the rationality of design scheme for vessel head project of China Erzhong.Simulation on different ratios of height and diameter of cylinder models during upsetting process between platens, we analyze changes of stress and strain in hard-deformation zone and central area in forgings under various reductions in uneven temperature field. We also research the relationship between size of hard-deformation zone and reduction, and find the relations between the stress in central area and instantaneous ratios under different ratios of height and diameter of deformation bodies, as well as the formation mechanism of intense shear bands in central area. At last, we draw a conclusion that in forging practice, choosing blanks with H0/D0≤1.0 is much better.When simulation different ratios of height and diameter during upsetting process between cone platens, we analyze the changes of stress, strain and temperature field, then we find when H0/D0≤1.0 (the end plane of blank completely contacted with anvil), the radial stress of central point has changed from tensile stress to compressive stress, so the blank is under tri-axial compression stress state, which has improved the quality of forgings and further optimized the upsetting technology.In compaction simulation to boss with 1:3 in vessel head project of China Erzhong, we discuss the feasibility of free slab forming technology and how to set process parameters. We also simulate the whole deformation process during slab forming in order to obtain the distribution of force and energy parameters in blanks. Comparing 3 different slab forming schemes, we have got the best design scheme to forge dish-shaped forgings with bosses. Now, we have finished simulation of vessel head with supporting ear handle and have developed qualified products.This simulation and calculation has provide reference basis for setting and optimizing process parameters during free die forging process of dish-shaped forgings used for nuclear power and gave beneficial information to improve quality of products.