Physical simulation experiment and evaluation for folding defect in forming of multi-cavity parts by multi-direction loading

Abstract

Folding, a common defect in plastic forming, is prone to occur and very complicated especially in the forming of multi-cavity parts by multi-direction loading, which is the most representative and difficult plastic forming process. Physical simulation experiment (PSE) with Plasticine provides an intuitive method for study of metal flow and folding defect. However, the reasonable PSE and evaluation of it are lack of understanding. In this work, taking a typical multi-cavity part, 316LN tee valve, as object, physical simulation experiment and evaluation for folding defect were investigated by considering the Plasticine composition, layered thickness, and material modeling, along with boundary friction. The results show that the oil-based clay Plasticine with layered thickness of 2 mm could accurately reflect material flow characteristics due to its good performance. Constitutive modeling of Plasticine based on the similar strain hardening index and proportional load, combined with similar friction conditions at room temperature could well macroscopically characterize the metal flow and folding defect evolution in actual forming process. The reliability and applicability of the physical simulation method proposed are further validated by comparative analysis of the material flow law and folding defect with finite element simulations under four representative loading paths.