When a specification calls out "MSS SP-55, latest revision" on a drawing or purchase order, it legally binds the supplier to inspect and accept castings based on those visual rules.
– Non-metallic materials (like sand or slag) trapped in the casting. Type IV: Gas Porosity – Small voids or bubbles caused by trapped gas. Type V: Chaplets mss sp-55 standard pdf
The standard, titled "Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components—Visual Method for Evaluation of Surface Irregularities," is a critical industry guideline published by the Manufacturers Standardization Society (MSS)0;91;. It provides a standardized visual methodology for assessing the surface quality of steel castings used in piping systems. 0;92;0;a1; 0;baf;0;d1; 1. Scope and Purpose When a specification calls out "MSS SP-55, latest
: While primarily used for valves and fittings, it applies to any steel casting used in piping systems where surface integrity is critical. Types of Irregularities Covered Type V: Chaplets The standard, titled "Quality Standard
levels of the irregularity, while the three on the right are considered unacceptable Application: