Whether you are an NDE level II inspector, a procurement engineer, or a foundry quality manager, the MSS SP-55 standard is your best ally in ensuring safe, reliable steel castings.
As of this writing (2025), the active revision is MSS SP-55 – 2022 (formerly 2017, 2011). Always check MSS.org for updates.
| Standard | Method | |----------|--------| | MSS SP-53 | Magnetic Particle Examination Method | | MSS SP-54 | Radiographic Examination Method | | MSS SP-93 | Liquid Penetrant Examination Method | | MSS SP-94 | Ultrasonic Examination Method | | MSS SP-112 | Visual and Tactile Method |
The standard includes dual units (inch to mm). The PDF typically lists inches first, with millimeters in parentheses. mss sp-55 standard pdf
The standard includes a set of 60 reference photographs. These photographs illustrate various types of common casting surface irregularities, including: Surface porosity Sand inclusions Cold shuts Surface scabs Surface cracks Visual Comparison Method
: For lost foam iron castings, discuss and agree upon defect acceptance criteria with the customer before production begins, as the standard requires mutual agreement for these applications.
: Minor surface ripples or very small pits that do not affect the wall thickness or strength. Unacceptable Whether you are an NDE level II inspector,
these represent defects that must be removed or repaired. Type of Irregularity General Acceptance Guideline Type I Hot Tears and Cracks Generally not acceptable in any visible degree. Type II Acceptable if within "A" or "B" visual limits. Type III Sand Inclusions Acceptable if within "A" or "B" visual limits. Type IV Gas Porosity Acceptable if within "A" or "B" visual limits. Type V-X
To effectively implement MSS SP-55 in a production or quality control environment, consider the following best practices:
This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. MSS SP-55 - Peninsula Alloy Inc. | Standard | Method | |----------|--------| | MSS
Inspectors often use a fingernail or a reference comparator gauge to feel the depth of an irregularity if a visual check is inconclusive.
The 2025 edition also addresses lost foam casting (evaporative pattern casting), a process where molten metal vaporizes a foam mold to create complex, precise castings. However, the standard includes an important caveat: application of MSS SP-55 to lost foam iron castings must be mutually agreed upon by the manufacturer and the end user, acknowledging the unique surface characteristics produced by this process.
If you provide the type of surface irregularity you're seeing (e.g., surface porosity, cracks), I can help you understand the likely causes and how to find the specific reference photograph in the MSS SP-55 standard PDF for a more accurate assessment. Share public link
Using brings consistency to the inspection process, reducing disputes regarding what constitutes a "good" versus "bad" surface.