Solution for intrusive porosity defects of zinc alloy die castings
Defect characteristics:The pores near or near the surface of the casting also exhibit a more regular shape, but the inner wall surface is smooth but not shiny. This is due to internal wall immersion in gas pollution or corrosion.
Visual inspection or x-ray inspection after processing.
(1) Volatile substances are present on the mold wall; there is no "complete" volatilization of water on the inner wall surface of the cavity, leaving a residue. When the mold cavity is filled with the die-cast alloy liquid, the gas is discharged, but there is nowhere to be found (the mold is alloy steel, no permeability). Only when immersed in the casting, will solidification leave a hole (sometimes not immersed in the product, causing a circular depression on the surface of the product).
(2) The mold leaks. Sometimes water leaks into the mold cavity.
(3) Drip water from a type sprayer, and “water” drops into the cavity during the mold.
(4) The mold temperature is too low, and volatile substances such as molds are not allowed to evaporate before the mold is molded.
(1) Increase the mold temperature so that volatile substances can evaporate completely in a short period of time (before the alloy liquid is immersed in the mold cavity).
(2) Make the preparations use correctly, evenly, without causing local overdose, and volatilize before death.
(3) The blowing must be uniform and thorough, and there must be no residual droplets on the surface of the mold cavity.
Cooling water must not leak into the mold cavity.
(5) The sprayer is well maintained. After spraying, there is still liquid dripping into the mold cavity.
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