Long Weld Neck Standard
Class 2500 Long Weld Neck Flanges
MSS SP-97 long weld neck flanges for Class 2500 service
Class 2500 Long Weld Neck flanges represent the highest standard pressure class for LWN configurations per MSS SP-97. These flanges are reserved for the most extreme pressure applications, typically in polyethylene production (LDPE/HDPE reactors), ultra-high-pressure research equipment, and specialized chemical synthesis vessels.
The forging requirements for Class 2500 LWN flanges are the most stringent in the industry. Each forging is individually heat-treated and tested, with comprehensive NDE including ultrasonic, magnetic particle, and liquid penetrant examination. Material certification includes full chemical analysis, tensile testing, and Charpy impact testing at the design minimum temperature.
Due to the extreme pressures involved, Class 2500 LWN flanges are available in a limited size range, typically NPS 1/2 through NPS 12. Ring-type joint face configurations are standard at this class, and specialized BX-series ring gaskets rated for Class 2500 service pressure are required.
