Massive, equiaxed voids with a sponge-like appearance. The Eight Levels of Severity
Immediate visualization of what a "Level 3" porosity looks like compared to a "Level 5."
Radiography (X-ray) is excellent for detecting macroscopic gas holes and shrinkage. However, microporosity—microscopic voids between metal dendrites—can sometimes slip past a standard X-ray. For highly stressed aerospace parts, engineers often combine ASTM E155 radiographic testing with destructive metallographic evaluations. astm e155 porosity levels pdf repack
This level of specificity removes ambiguity and ensures your supplier knows exactly what is being required.
The inspector compares the radiograph of the part (the "production radiograph") side-by-side with the ASTM reference radiograph. Massive, equiaxed voids with a sponge-like appearance
For a typical , you will find 5 distinct severity levels illustrated for each type of porosity. Here is what each level represents in practical terms:
| Severity Level | Description | Typical Application | |----------------|-------------|---------------------| | | Very fine, widely scattered pores. Barely visible under magnification. | Aerospace structural components | | Level 2 | Small pores, moderate frequency. Slight loss of material density. | General automotive castings | | Level 3 | Medium pores, clearly visible. Beginning of cluster formation. | Pump housings, non-critical parts | | Level 4 | Large pores, high frequency. Obvious density reduction. | Decorative or very low-stress parts | | Level 5 | Very large, coalesced pores. Severe structural degradation. | Usually rejection threshold | For highly stressed aerospace parts, engineers often combine
To effectively utilize ASTM E155 porosity data within a manufacturing pipeline, quality assurance teams follow a structured inspection workflow:
Because official ASTM reference radiographs are proprietary, high-resolution physical films or specialized digital reference images sold directly by ASTM, independent testing labs and engineering firms often create internal "repacks." What an Engineering "Repack" Document Includes: