Numerical Three Reconstruction Of Cast Defects And Effect Of Cast Defects On Service Performance Of Casting

Casting is contains a large number of complex physical and chemical processes of metal forming methods. In the casting process with a variety of casting defects such as shrinkage, porosity, cracks, deformation, etc. during solidification, shrinkage defects is very large damage on the casting quality. Owing to casting structure, metal smelting, process design, the casting during solidification will appear more or less shrinkage defects. Exist of shrinkage defects not only undermine the local continuity of the material, but also reduce significantly the mechanical properties of materials, making the material can premature fracture and failure. And shrinkage defects will damage casting quality, seriously affecting the service performance of the castings.In casting production process, the many studies have focused on improved technology programs or optimize the product structure to minimize the defect rate. But with little consider for the presence of casting defects in the field of structural analysis, resulting in the result of parts of the service performance and the actual analysis with defective castings are very different. However, it is because of the existence of these local defects will make the casting premature failure and damage.In order to complete and accurate analysis of the stress and fatigue properties of casting containing porosity, casting simulation, structural analysis and fatigue analysis are organically combined, give full consideration to the impact of mechanical properties and service characteristics of casting containing porosity. The results of the analysis of the study methods compare with the results of the analysis of the actual casting will appear more real and more consistent.In this paper, the numerical reconstruction method to get the porosity defect characteristic in casting specimens, and defect information is mapped to the finite element mesh model. On this basis, non-homogeneous finite element model of casting containing porosity defects will execute stress analysis and fatigue analysis, obtaining the effect of defect feature on service performance and fatigue life. Analysis found that the mechanical properties of defect-free casting specimen and the specimen of defective castings, the stress distribution of the porosity defects in the casting than the defect-free castings stress distribution. And these of the stress concentration is not the same, with the increasing of porosity defects, the stress concentration have vast change in casting containing porosity defects; In addition. Analysis found that the fatigue performance of defect-free casting specimen and the specimen of defective castings, whether it is in the fatigue life or it is in the fatigue damage, its fatigue life and cycle times are quite different. And with the increasing of porosity defects, fatigue failure and fatigue damage will appear a sharp decline.In this paper, the numerical simulation of casting analysis and the actual casting analysis will make more consistent, so that it can better promote and improve the quality of castings, ensure the stability and reliability of the castings in the service period, the study method on the casting process design and optimization will have a certain theoretical significance and practical value.