It's important to determine the type of Die Casting Mould before trying to fix it, because each requires a completely different approach, although they can look similar. To be sure you've accurately identified the type of porosity defect you're dealing with, use five- to ten-power magnification.

We'll focus on gas porosity, since it's the bigger problem of the two.

Gas porosity is one of the most significant problems in die casting. High gas content eliminates heat-treating or welding steps and makes the strength of the casting unpredictable. Here are three major sources of gas porosity in die-castings:

Trapped air

Steam

Gas from lubricant

Trapped Air

Turbulence may allow air bubbles to be trapped in the metal. The problem is that the bubbles remain trapped when the Die Casting Parts solidifies. Air can be trapped as follows.