A Study On Liquid Forging Of Al-Si Alloy

Ordinary foundry, for example, sand casting, metal-die casting, has well grown defects such as shrinkage cavity or porosity. Liquid forging is a new metal-forming technology. Using Liquid forging instead of ordinary foundry to obtain parts is discussed in this paper.In the experiment, ZL102 is used as raw materials, orthogonal experiment process is adopted, the parts of ZL102 alloy are manufactured by liquid forging. The effects of liquid forging processing parameters on the casts'mechanical properties and microstructure are investigated.The results of experiments are listed: (1) Crystals of liquid forging are finer than that of metal-die casting. In liquid forged alloys, the grains are smaller, the first dendrite arm spacing is 62.0μm, the second dendrite arm spacing is 46.6μm, the alloy tends to be columnar structure, as a result, the mechanic properties are considerably better;(2) The influence order of processing parameters on tensile strength is the intensity of pressure, the pouring temperature, the mold temperature, and the most important factor to plasticity is the pouring temperature;(3) The intensity of pressure is the most remarkable factor that influence the casts'mechanical properties and microstructure. When its value is 60MPa(200kN), the strength and plasticity is perfect, once exceeds 60MPa, the strength decreased, but plasticity in some sort increased. The average tensile strength in ordinary foundry parts is 120 MPa, compared with metal-die castings, it can improve the tensile strength up to about 144% in liquid forging;(4) Mechanical properties are best by taking liquid forging process. In practice, based on the request, the parameters can be selected to attain better strength or plasticity alloys. The optimal processing parameters are that: the intensity of pressure is 60MPa(200kN), the pouring temperature is 620℃and the mold temperature is 380℃.