The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry developed the SP-55 standard to bridge the gap between "perfect" aesthetics and "functional" integrity. When working with pressure-containing steel parts, a smooth surface isn't just about looks—it’s about preventing fatigue, corrosion, and structural failure. The Scope of MSS SP-55
If your customer specifies , do not substitute ASTM A802 without approval. mss sp55 standard pdf work
MSS SP-55 is the industry standard for evaluating the surface quality of steel castings used in valves, flanges, and fittings. It provides a visual and tactile framework to ensure that components are safe, functional, and free from critical defects. The Manufacturers Standardization Society (MSS) of the Valve