When inspecting a casting, the inspector compares the physical component to the reference photographs in the MSS SP-55 manual.

Consistency in evaluation leads to higher reliability in critical sectors like oil & gas and power generation. Are you using the latest MSS SP-55:2025 guidelines for your QC process?

The standard categorizes surface imperfections into 11 distinct types. If you have the PDF open during an inspection, you can quickly navigate to the specific category of the defect you are seeing:

Do you need assistance comparing SP-55 to (like ASTM A802)?

Generally, the price for the official PDF is in the range of several hundred dollars, reflecting the significant work that goes into its development and maintenance.

The is more than just a document—it is a critical tool for ensuring the safety and reliability of steel castings in demanding piping systems. From understanding the six types of surface irregularities to applying the visual method with proper lighting, this standard equips quality professionals with an objective, repeatable framework.

The formal announcement of this revised standard was made in July 2025, and it was soon approved by the American National Standards Institute (ANSI) as a revised American National Standard. This update demonstrates the standard's ongoing evolution to meet the demands of the power generation, oil and gas, and chemical processing industries.