Numerical Study Of Al-Si Alloy Rolling Defect Mechanism

Al-Si alloy material which is based on silicon as major alloying elements,because the type of alloy material contains high silicon, the low melting point and thegood liquidity are its characters, the foil that produced by alloy material mainly beused to manufacture the addition of aluminum alloy welding materials and coatingmaterials. However, by adding silicon, the tensile strength and elongation of thematerial are decreased obviously, so it is likely to cause the crack edge and beltdefect, especially in the rolling mill. For the complexity of rolling production, therolling force and rolling temperature and other parameters can only be obtained bythe measurement of the deformation through the field test. However, the surroundingequivalent stress and equivalent strain of the silicon grains, which is closely relatedto the rolling process and material properties cannot be obtained by test. Therefore,in this article, we use DEFORM finite element analysis software to track and analyzethe rolling process; meanwhile, establish the damage model of different grain shapesize, and the finite element model of the default crack and John-Cook. By analyzingthe parameters of the effect stress and strain around grain in rolling process, theinfluence law of silicon grain shape and size to the performance of plate can beobtained. Finally use the method of test to verify the result of simulation. The resultof the simulation analysis will have definite instruct meaning and reference value tothe actual production. The main research contents as follows:1. In the past, few scholars analyzed the board contain reinforced particle by thefinite element analysis method, with this prerequisite, in modeling process, usingbond condition to decide the contact relation between reinforced particle andaluminum matrix and solving the difficulties in the modeling process.2. Analyzing the simulation results of the board contain the spherical andlamellate silicon, simulation results show that: the lacerate phenomenon caused bythe lamellate silicon is more obvious than the spherical that is because the deformation resistance of silicon greater than the aluminum matrix which leading tothe aluminum matrix accumulation and the stress concentration.3. Analyzing the finite element method contain the broken grain crack, theresults show that: the equivalent stress on the position contain broken grain and crackis greater than the others, so we need improve the grain shape and reduce thepossibility of crack expansion by the heat treatment process tempering and annealingwhich can promote the dynamic recovery and dynamic recrystallization.4. We established the finite element model of the rolling process that is based onthe John-Cook damage model and simulated the cracked edges phenomenon of therolling process.5. The correctness of the simulation results are verified by the rolling test,tensile test and scanning electron microscopy experiment.