Casting hot crack growth prediction method based on numerical simulation

Abstract

The invention belongs to the field of casting numerical simulation, and discloses a casting hot crack growth prediction method based on numerical simulation, which comprises the following steps of S1,carrying out numerical simulation on the solidification process of a to-be-tested casting to obtain the thermal stress field data of the to-be-tested casting, and determining a hot crack initiation position according to the thermal stress field data and a hot crack criterion; S2, establishing a sub-model containing a hot crack initiation position, determining an initial position of the hot crackgrowth in the sub-model and a corresponding growth sub-step, and inserting an initial hot crack at the initial position of hot crack growth to obtain an initial hot crack form; and S3, predicting thehot crack growth according to the sub-model. The method can accurately predict the hot crack initiation and growth process in the casting process, and provides a basis for optimizing the casting process and improving the hot crack defect.

Description

Technical field [0001] The invention belongs to the field of casting numerical simulation, and more specifically, relates to a method for predicting the growth of casting hot cracks based on numerical simulation. Background technique [0002] Casting is one of the basic processes of the modern equipment manufacturing industry. Casting technology is widely used in aviation, aerospace, rail transit, ships, automobiles and other fields. Casting hot cracks are one of the most common defects in the casting production process. When the cracks in the castings initiate and start to expand, the life of the casting products will be greatly reduced, and the castings may even be directly scrapped. Thermal cracks mainly occur in the quasi-solid phase area during the solidification process of the casting, that is, in the later stage of the solidification of the casting, the solid phase has formed a complete skeleton and began to shrink linearly. In the part where the feeding is insufficient, d...

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Problems solved by technology

However, at present, there are few numerical simulation studies on the initiation and propagation of casting hot cracks, which cannot effectively predict the initiation and propagation of hot cracks.

Specifically, on the one hand, the mechanism of hot cracking has not been thoroughly explained. It is generally believed that the initiation of hot cracks is the result of the joint action of insufficient feeding in the quasi-solid region and tensile stress. There are many criteria for hot crack initiation, most of which are The criterion only considers the influence of one of the factors, and can only give its tendency. It needs to be combined with other simulation results (such as temperature field, stress field, strain field, etc.) to analyze whether it will There are also some criteria that consider the influence of the stress state when thermal cracks occur, but how to use them for the prediction of crack growth has not been reported; on the other hand, there is no relevant research that considers the thermal crack growth during the casting process.

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