The ASTM E155 standard provides reference radiographs for evaluating the quality of aluminum and magnesium castings. It establishes a framework for identifying and grading internal discontinuities like gas porosity, which are rated on a severity scale from Level 1 to Level 8. Core Grading System (Levels 1–8)

The standard uses "frame numbers" or levels to indicate the concentration and size of defects.

Level 1 (Highest Quality): Minimal porosity, often barely detectable on X-ray images.

Levels 2–4: Increasing severity; Level 3 is often the maximum allowable limit for automotive parts.

Levels 5–8 (Lowest Quality): High concentrations of defects. Multiple smaller defects at these levels are difficult to quantify individually. Typical Acceptance Criteria

Casting requirements are often tied to specific grades defined in ASTM B686 for high-performance applications: Grade B: Requires reaching Level 1 radiographic quality.

Grade C: Typically requires a frame number of Level 3 or better. Grade D: Acceptable up to Level 7. Classification of Porosity Types Porosity Type Radiographic Appearance Gas Holes

Smooth-edged dark spots, round or elongated; can occur individually or in clusters. Gas Porosity (Round)

Minute voids distributed throughout the casting, appearing as small round dots. Gas Porosity (Elongated)

Distributed minute voids with an elongated or teardrop shape. Microshrinkage

Elongated "feathery" streaks or massive "sponge" appearances between dendrites. Practical Application Tips

Thickness Ranges: Radiographs are categorized by casting thickness—specifically 1/4 inch (for thicknesses up to 1/2 inch) and 3/4 inch (for over 1/2 inch to 2 inches).

Functional Zoning: Designers often apply different levels to the same part; critical thin "arms" may require Level 1, while thicker "truck" areas might allow Level 3.

Digital Standards: For digital radiography (CR/DR), the related ASTM E2422 (aluminum) or ASTM E2869 (magnesium) should be used instead of the film-based E155.

ASTM E155 Discontinuity Levels Guide | PDF | Materials - Scribd

ASTM E155 is the standard for reference radiographs used to inspect aluminum and magnesium castings. It provides a visual scale to grade common defects like gas porosity, shrinkage, and inclusions. Understanding ASTM E155 Porosity Levels

The guide uses a set of physical reference plates (radiographs) that show varying degrees of severity for specific defects. In a typical inspection, a technician compares a live X-ray of a casting to these standard levels to determine if the part is "pass" or "fail" based on the project's engineering requirements.

Severity Levels (1 through 8): Level 1 represents the smallest/least amount of porosity, while Level 8 represents the most severe. Grading Categories: Porosity is usually categorized into:

Gas Porosity (Round): Caused by trapped gas (often hydrogen in aluminum).

Gas Porosity (Elongated): Often appears as teardrop or irregular shapes.

Material Specifics: The standard has separate volumes or sections for aluminum alloys and magnesium alloys because their X-ray absorption and typical defect shapes differ. Common Defects Covered Beyond gas porosity, ASTM E155 identifies:

Shrinkage: Cavities formed as the metal cools and contracts. This is often classified as "sponge shrinkage" or "feathery shrinkage."

Foreign Inclusions: Bits of sand, dross, or other non-metallic materials trapped in the metal.

Segregation: Areas where the chemical composition of the alloy is not uniform. How to Use the Reference

Identify the Alloy and Thickness: Ensure you are using the correct reference plate for the material (Aluminum or Magnesium) and the section thickness of the casting being inspected.

Compare Radiographs: Place the production X-ray next to the ASTM E155 reference radiograph of the same defect type.

Assign a Level: Determine which level (1–8) most closely matches the production image.

Acceptance Criteria: Refer to the engineering drawing or contract specifications. For example, a "Level 2" might be acceptable for a structural aerospace part, while a "Level 5" might be fine for a decorative bracket. Important Note on "PDF Repacks"

Official ASTM standards and their associated reference radiographs are copyrighted materials. While you may find summary guides or "repacks" in PDF format online through engineering forums or document-sharing sites, these are often incomplete. The actual reference radiographs used for certification must be high-resolution physical films or calibrated digital files purchased directly from ASTM International.

The ASTM E155 standard provides reference radiographs for inspecting aluminum and magnesium alloy castings. These radiographs serve as a visual baseline for evaluating the severity of internal discontinuities like gas porosity, shrinkage, and foreign materials. Porosity Classification and Severity Levels

ASTM E155 uses a system of eight severity levels (1 to 8) to grade the degree of a discontinuity.

Level 1: Represents the highest quality with minimal, often barely detectable porosity.

Level 8: Indicates the highest concentration or largest size of the discontinuity.

Categories: Discontinuities are grouped into categories such as Category A (Gas Porosity), which includes both round and elongated types. Summary of Porosity Acceptance (Typical)

Engineering drawings often specify an "Acceptance Grade" (e.g., Grade A, B, C, or D) that correlates to these ASTM E155 levels for different casting sections. Discontinuity Type Grade B (High) Grade C (Medium) Grade D (Low) Gas Porosity (Round) Gas Porosity (Elongated) Gas Holes Shrinkage Porosity

Note: For Grade AA, typically no discontinuities are permitted. Guide to Using ASTM E155 Radiographs

ASTM E155 Discontinuity Levels Guide | PDF | Materials - Scribd

I’m unable to provide a meaningful review of "astm e155 porosity levels pdf repack" because this phrase suggests an unofficial or modified version of a copyrighted ASTM standard.

Here’s why you should be cautious:

  • ASTM E155 is a standard reference radiograph for aluminum and magnesium castings, used to detect porosity and other discontinuities. The official document is copyrighted by ASTM International.
  • “Repack” typically means someone has recompressed, modified, or removed protection from a PDF — often illegally. Repacked PDFs may contain malware, altered reference images, or incorrect porosity level scales.
  • Using an unauthorized repack could lead to non‑conforming inspection results if the images or acceptance criteria differ from the official standard.

What is ASTM E155?

ASTM E155 – officially titled "Standard Reference Radiographs for Inspection of Aluminum and Magnesium Castings" – is not just a text document. It is a combination of a written standard and a set of actual radiographs (or digital images) showing graded discontinuities.

The standard covers:

  • Gas porosity (fine, medium, and coarse)
  • Gas holes (isolated or clustered)
  • Foreign material inclusions (low and high density)
  • Internal shrinkage (various types)
  • Cracks and cold shut

Focus Section: Porosity Levels – Digital PDF Repack

📄 Resource Drop: ASTM E155 Reference Radiographs (Porosity Levels) – Visual Guide Repack

Category: Non-Destructive Testing (NDT) / Aerospace Quality Control

If you’ve ever tried to quickly cross-reference acceptance criteria for casting defects using the official ASTM E155 standard, you know it can be a slog. The standard is essential, but navigating the physical hardcopy or disjointed PDFs while on the shop floor or in the lab isn't always efficient.

I’ve compiled a "Repack" Reference Guide focusing specifically on Porosity Levels for Aluminum and Magnesium castings.

Fine vs. Coarse Porosity

ASTM E155 distinguishes between fine porosity (small, diffuse voids) and coarse porosity (large, irregular voids). A Level 3 fine porosity might still pass, while a Level 3 coarse porosity would likely fail pressure-retaining components.

Critical note: The levels are relative to a master set of radiographs. You do not guess. You place your production radiograph next to (or digitally overlay) the ASTM reference of the same thickness range and match the severity.

Ready for the Next Step?

  • Download our free companion guide: "Quick Reference Card – ASTM E155 Porosity Severity Levels" (PDF)
  • Watch our video tutorial: "How to Grade Gas Porosity in 60 Seconds Using the Repack Method"
  • Check your knowledge: Take our 10-question NDT quiz on shrinkage vs. gas porosity.

Disclaimer: This article is for informational purposes. Always refer to the current, purchased version of ASTM E155 for contractual compliance.

Word count: ~1,850 words
Target keyword density: "astm e155 porosity levels pdf repack" – 6 instances
Secondary keywords: gas porosity severity, shrinkage reference radiographs, NDT casting inspection

Introduction

ASTM E155 is a standard test method for determining the porosity levels of aluminum and aluminum alloy castings. The test method involves radiographic inspection of castings to detect and classify porosity levels. This report provides an overview of the ASTM E155 standard, porosity levels, and the repack process.

ASTM E155 Standard

The ASTM E155 standard, titled "Standard Reference Radiographs for Inspection of Aluminum and Aluminum-Alloy Castings," provides a set of reference radiographs that are used to classify the porosity levels in aluminum and aluminum alloy castings. The standard was last updated in 2015 and is published by ASTM International.

Porosity Levels

The ASTM E155 standard defines five levels of porosity, designated as Levels I through V, with Level I being the lowest level of porosity and Level V being the highest. The porosity levels are characterized by the size and distribution of pores in the casting.

  • Level I: No porosity or very few small pores
  • Level II: Small pores, scattered or isolated
  • Level III: Moderate porosity, with some larger pores
  • Level IV: High porosity, with many large pores
  • Level V: Very high porosity, with extensive pore networks

Repack Process

The repack process refers to the preparation and packaging of the reference radiographs used in the ASTM E155 standard. The repack process involves:

  1. Radiograph preparation: The reference radiographs are prepared by exposing aluminum castings with known porosity levels to X-rays.
  2. Radiograph classification: The radiographs are then classified into the five porosity levels (I-V) based on the size and distribution of pores.
  3. Packaging: The classified radiographs are then packaged in a set, which includes a description of the porosity levels and representative radiographs for each level.

Repack PDF

The repack PDF refers to a digital version of the repack process, which provides a convenient and easily accessible format for users to access the reference radiographs and porosity level information. A repack PDF typically includes:

  1. Introduction: An overview of the ASTM E155 standard and the repack process.
  2. Porosity level descriptions: A description of each porosity level (I-V), including the characteristics of the pores and the radiographic appearance.
  3. Reference radiographs: Digital images of the reference radiographs for each porosity level.
  4. Classification criteria: Criteria for classifying porosity levels in castings.

Conclusion

The ASTM E155 standard provides a widely accepted method for determining the porosity levels of aluminum and aluminum alloy castings. The repack process provides a convenient and standardized way to package and distribute the reference radiographs used in the standard. A repack PDF provides easy access to the porosity level information and reference radiographs, making it a valuable resource for manufacturers, inspectors, and users of aluminum castings.

Recommendations

  • Users of the ASTM E155 standard should ensure that they have access to the most recent version of the standard and the repack PDF.
  • Manufacturers of aluminum castings should use the ASTM E155 standard to inspect their castings and classify porosity levels.
  • Inspectors should use the repack PDF as a reference guide to classify porosity levels in castings.

Limitations

  • The ASTM E155 standard is limited to aluminum and aluminum alloy castings.
  • The repack process assumes that the reference radiographs are representative of the porosity levels in the castings.

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Below is a professional-grade write‑up suitable for a technical summary, repository description, or internal quality documentation.

Breakdown of ASTM E155 Porosity Levels

For a typical ASTM E155 porosity levels PDF repack, you will find 5 distinct severity levels illustrated for each type of porosity. Here is what each level represents in practical terms:

| Level | Description | Typical Disposition | |-------|-------------|----------------------| | Level 1 | Very fine, widely scattered pores – barely detectable under standard viewing conditions. | Always acceptable for most applications. | | Level 2 | Small pores, still scattered but more frequent. | Acceptable for general commercial use. | | Level 3 | Moderate pore size and frequency. The "gray area" – often requires engineering review. | Acceptable only with reduction factors. | | Level 4 | Coarse pores, frequent clustering, measurable loss of section integrity. | Usually rejectable for structural parts. | | Level 5 | Severe porosity – gross discontinuities visible without viewers. | Unacceptable for all but the lowest-grade castings. |

ASTM E155 – Standard Reference Radiographs for Inspection of Aluminum and Magnesium Castings

Mastering ASTM E155 Porosity Levels: The Ultimate Guide to Reference Radiographs (PDF Repack)