Causes And Solutions For Die Casting Defects
1. Flow marks, stripes
Characteristics: The surface of the casting exhibits a localized sag smooth texture that is consistent with the flow direction of the molten metal. This defect has no development tendency and can be removed by polishing.
2. Cold insulation, cold connection
Features: A gap in which a lower temperature metal stream abuts but does not fuse. It presents an irregular linear shape, both penetrating and non-penetrating, and has a tendency to develop under the influence of external forces.
3. Bruises, strains, scratches, sticking scars
Characteristics: In the direction of the demoulding, due to the adhesion of the metal, the inclination of the mold is too small to cause a trace of the surface of the casting, which is called a strained surface when it is severe.
4. Sag, shrinkage, suffocation, collapse
Features: The part of the casting has a concave surface on the smooth surface, and its surface is naturally cooled.
5. Bubbles, bubbling
Features: Under the skin of the casting, the bubbles formed by the accumulation of gas bulge.
6. Air holes
Characteristics: The shape of the gas formed inside the die-casting part is relatively regular, and the surface is relatively smooth.
Characteristics: In the process of condensation casting, the shape is irregular due to insufficient internal compensation, and the surface is rough.
Features: The smooth stripe on the surface of the casting is visible to the naked eye, but it can not be felt by hand. The color is different from the texture of the base metal. It can be removed with a few rubs of 0# abrasive cloth.
Characteristics: The alloy matrix on the casting is broken or broken to form a filament-like gap, which has two kinds of penetration and non-penetration.
Cracks can be divided into cold cracks and hot cracks. Their main difference is that the metal at the crack of the cold crack casting is not oxidized, and the metal at the crack of the hot crack casting is oxidized.
10. Under-casting, insufficient pouring, unclear outline, and corner defects
Characteristics: The molten metal is not filled with the cavity, and the incomplete filling portion appears on the casting.
11. Imprints, putt impressions, inserts or moving blocks splicing impressions
Features: The surface of the casting is exposed by the mold cavity and the protruding and concave marks left by the splicing of the push rod, the insert, the movable block and the like.