: The standard is designed for general use on any 4 in. x 5 in. (100mm x 125mm) area of a casting.
The is a critical document for the valve and fitting industry, officially titled the "Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components – Visual Method for Evaluation of Surface Irregularities." mss sp 55 pdf
The primary goal of the MSS SP-55 standard is to ensure that steel castings are free from surface irregularities that could compromise their structural integrity or performance. It is intended to supplement ASTM specifications like A216, A217, and A351 by providing a more detailed visual guide for quality control. : The standard is designed for general use on any 4 in
MSS SP-55 includes a comparison table (Table 1) that correlates its acceptance criteria with other industry comparators, such as those from Castings Technology International (CTI) or the SCRATA standard. This helps manufacturers who may use plastic replicas (comparators) instead of photos to ensure they meet the minimum requirements of SP-55. Where to Find the Official PDF The is a critical document for the valve
Because the printed version published by MSS is the "official" rendering due to variations in digital viewing environments, it is recommended to purchase the most current edition directly from authorized distributors: MSS SP-55-2001 - Peninsula Alloy Inc.