Casting Defects Cheat Sheet

10 Casting Defects

10 metal casting defects with pictures, descriptions, and causes. So you can identify and fix your casting defects!

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Guide to metal casting defects

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1. Bent or Twisted Defect

Bend or twist casting defects occur when the part bends or twists out of desired shape.

Potential Causes

2. Misrun or Short Pour Defect

Misrun or short pour casting defects can be identified by holes or areas where the metal didn’t fill the mold, creating an incomplete part.

Potential Causes

3. Parting Line Shift Defect

If the mold cope and drag misalign, you may notice an offset/uneven appearance to your casting, occurring at the parting line.

Potential Causes

4. Flash Defect

Casting flash occurs when metal leaks out of the mold, creating excess surface area.

Potential Causes

5. Porosity Defect

Metal casting porosity is localized round holes in the part.

Porosity is perhaps the most well-known casting defect. There are several distinct “types” of porosity.

Potential Causes

Unlike hydrogen gas porosity, this type of porosity can be caused by your metal casting method. For example, sand castings and die castings typically have more porosity defects than permanent mold castings. Why? In sand casting, metal is dumped into the mold. In die casting, metal is high-pressure injected into the mold. In permanent mold casting, metal is gravity-fed, controlled by a tilt pour press. This creates less turbulence during the pouring process, resulting in less porosity.

6. Hydrogen Gas Porosity Defect

Hydrogen gas porosity appears as small holes throughout the metal casting.

Potential Causes

7. Inclusion Defect

Inclusion defects occur when small particles trapped in the mold or metal create porosity or poor surface finish on a casting.

Potential Causes

8. Shrink Defect

Shrinkage appears as dips, sinks, and voids in a casting.

Potential Causes

9. Crack Defect

Cracking defects are lines splitting the casting surface.

Potential Causes

10. Rough Surface Finish Defect

Surface finish defects occur when the casting has a high RMS surface finish that is out of spec.

Potential Causes

The average as-cast permanent mold surface finish is 200 to 400 RMS. This is smoother than sand casting (typically 300 to 560 RMS), but rougher than die casting (typically 20 to 120 RMS).

Stop Casting Defects

The best way to avoid defects is to choose an experienced supplier who will produce quality castings from the start! Contact us to learn more.