Series B Class 600 Flanges

Series B Class 600 flanges deliver high-pressure capability for large-diameter piping while maintaining the weight advantages of the API 605 design philosophy. At Class 600, the absolute weight of large-diameter flanges becomes a major logistical consideration, and the Series B reduction can make the difference between standard and special rigging requirements.

The reduced bolt count in Series B means that each bolt carries a greater share of the total load, requiring more precise torque control during assembly. Hydraulic stud tensioners are standard practice for Series B Class 600 flanges at sizes above NPS 30, and multi-pass tensioning sequences are typically specified to achieve uniform gasket loading.

These flanges are used in high-pressure gas transmission, power plant main steam and reheat piping, and petrochemical process units handling hydrocarbons at elevated pressures. Material specifications and NDE requirements are identical to Series A at the same pressure class.