X-Ray Testing in Die Casting: Ensure Quality While Reducing Costs

Have you ever encountered a situation where die-cast parts were already in mass production before discovering consistent internal defects? By then, it’s too late to correct the mold. X-ray testing can detect defects in die-cast parts early on, saving both time and costs. The following article will provide a detailed introduction to X-ray testing for die-cast parts.

What Is X-Ray Testing for Die-Cast Parts?

X-ray testing utilizes X-ray radiation to detect internal defects within die-cast components.

As X-rays penetrate materials, they create images at varying depths. By analyzing the images on X-ray film, we can pinpoint defect locations. This is because defects in die-cast parts exhibit distinct density differences compared to normal alloy material. 

Higher-density areas absorb X-rays more effectively, appearing lighter on the film. Lower-density areas absorb X-rays less, appearing darker on the film.

Similarly, inclusions like steel chips within the casting will also appear darker on the image.

X-ray testing stands as one of the most effective non-destructive testing methods for die-cast components.

Why Is X-Ray Testing so Crucial for Die-Cast Components?

Ensuring Die Casting Quality

For die-cast parts, surface finish, mechanical properties, and dimensional accuracy are all vital quality indicators. Surface quality can be assessed through visual inspection, while dimensional accuracy is measured using instruments like coordinate measuring machines. 

However, whether mechanical properties meet industry standards is heavily dependent on internal defects within the casting—defects that are often difficult to detect. 

X-ray testing utilizes the differing radiation absorption capacities of materials with varying densities to generate internal images. This allows for the detection of internal defects or impurities without damaging the casting.

We can guarantee that Sunrise’s die-cast parts will not reveal mechanical performance issues only during the assembly stage. This is because we employ X-ray testing to detect internal defects early on and make timely adjustments.

Cost Savings

Die casting is a precision metal forming technology where even minor temperature fluctuations or raw material defects can cause severe casting flaws. 

Detecting consistent internal defects during small-batch trial production saves significant time and cost compared to discovering them only during mass production. 

Identifying consistent defects on X-ray films enables timely mold optimization or parameter adjustments.

What Defects Can Be Detected in X-Ray Testing?

Gas Porosity

Gas porosity appears as round or elongated shadow spots on X-ray film images. These pores typically measure 0-1mm in diameter. This defect usually arises when moisture on the mold’s inner surface fails to evaporate promptly during the metal’s transition from molten to solid state. Gas porosity can compromise the mechanical strength of die-cast components. For parts used in marine applications, it may accelerate corrosion in salt spray environments.

Shrinkage

Shrinkage is another common internal defect in die casting. It appears as protruding, thread-like, or jagged dark areas on X-ray film images. Significant thickness variations in the casting wall (e.g., differences exceeding threefold) during solidification can cause uneven temperature distribution, leading to shrinkage.

Cracks

Cracks are categorized as hot tears and cold cracks. Hot tears appear on X-ray film as coarse, dark lines of varying widths, resembling tree branches with numerous forks. Cold cracks manifest as single, continuous black lines that appear narrow and sharp.

Cold Shut

Cold shut is a defect originating during the pouring process. It can result from slow pouring speed, interrupted pouring, or excessively low pouring temperature. Visually, cold shut appears as a deep line with a distinct outline and smooth edges.

Inclusions

Inclusions typically manifest as irregularly shaped holes. Impurities in molten metal may include foreign metals, sand, oxides, or slag.

Conclusion

Internal defects are indeed a critical focus during the quality inspection of die-cast components. 

If you’ve ever suffered losses due to internal defects in die-cast parts and are seeking a die-casting manufacturer capable of X-ray testing, please contact Sunrise. We will use X-ray testing to identify defects in your castings. We confirm that no quality issues will occur during assembly.