Reasons and solutions for cracks in aluminum die casting

Visual inspection: Put the casting in alkaline solution, the cracks are dark gray. The destruction and cracking of the metal matrix are straight or wavy, with narrow and long lines, which have a tendency to develop under the action of external forces.

Causes of cracks in aluminum alloy castings:

1) The iron content in the alloy is too high or the silicon content is too low; the content of harmful impurities in the alloy is too high, which reduces the plasticity of the alloy; the aluminum-silicon alloy, aluminum-silicon-copper alloy contains too much zinc or copper; the aluminum-magnesium alloy contains Too much magnesium

2) The mold retention time is too short, and the pressure holding time is short; the wall thickness of the casting has drastic changes

3) The local packing force is too large, and the force is uneven when ejected

Solutions and prevention methods:

1) Correctly control the alloy composition. In some cases: pure aluminum ingots can be added to the alloy to reduce the magnesium content in the alloy; or aluminum-silicon master alloys can be added to the alloy to increase the silicon content

2) Increase the temperature of the mold (mold); change the structure of the casting, adjust the core pulling mechanism or make the push rod force evenly

3) Increase the draft angle and use strong release agent locally

4) Increase mold retention time and increase pressure holding time



Post time: Aug-24-2020