It should be known to many people that aluminum and aluminum alloys are recognized as the ideal materials for future automobiles. For aluminum. The application of die-casting aluminum parts will greatly reduce the weight of the whole vehicle and reduce the emission of pollutants while improving the dynamic performance of the vehicle.
However, there is a big gap between aluminum and steel, and due to the limitations of current production technology, the cost of aluminum is high, which limits its application in automobile.
Defect characteristics, causes and prevention methods of aluminum alloy die casting: flow mark and pattern net hairfin brittle crack, shrinkage cavity and porosity characteristics and inspection method.
Appearance inspection: there are stripes on the surface of aluminum alloy die casting which are consistent with the flow direction of liquid metal, and there are obvious visible lines which are different from the metal matrix color without direction, and there is no development trend.
Appearance inspection: the surface of the die casting has the trace of net hair like protrusion or depression, which expands and extends with the increase of die casting times.
Appearance inspection or metallographic examination: the alloy grain is coarse or very small, which makes the casting easy to fracture or smash.
Appearance inspection: when the casting is placed in the alkaline solution, the crack is dark gray, and the damage and crack of the metal matrix are linear or wavy, and the striation is narrow and long. Under the action of external force, there are two kinds of cracks: penetrating and non penetrating
Anatomic appearance inspection or flaw detection; the surface of shrinkage cavity is dark and not smooth, and the shape of the hole is irregular. The large and concentrated hole is shrinkage cavity, and the small and scattered hole is shrinkage porosity.
