Cold Shut vs. Crack: Identifying and Solving Widespread Casting Defects in Investment Casting

In an investment casting communication group, a member posted the photo shown in Figure 1 with the question: “Experts, what causes these widespread cracks?”

Figure 1: Cold shut on the surface of a casting

From the way the question was phrased, it is clear that the person is relatively new to precision casting—even mistaking a basic cold shut (or misrun) defect for a crack. This also highlights room for improvement in foundational knowledge among some professionals in our industry.

There are two main reasons why this defect is identified as a cold shut rather than a crack:

1. The defect appears in non-fixed locations, unlike cracks which typically occur in specific, repeatable areas.

2. The edges of the defect are generally rounded, a distinctive characteristic of cold shut or misrun defects.

While the defect itself is straightforward, the key issue—and the focus of this article—is why it occurs over such a large area.