In 2026, the flange industry witnessed critical updates to two key standards: MSS SP-44-2026 Steel Pipeline Flanges and ASTM A988/A988M-26 Standard Specification for Hot Isostatically-Pressed Stainless Steel Flanges, Fittings, Valves, and Parts for High Temperature Service. These documents not only revise technical parameters but also reflect the industry’s deep embrace of safety, traceability, and advanced manufacturing technologies.
MSS SP-44-2026: Refined Control for Large Diameter Pipeline Flanges
For large diameter flanges from NPS 12 to 60, the new standard tightens requirements across multiple dimensions:
- Materials and Traceability: Added ASTM A515/A515M plate material to the weld compatibility list, and aligned the carbon equivalent calculation method with MSS SP-75. More importantly, the standard now mandates that manufacturers establish a quality control program with明确规定 for traceability and record retention. The detailed information required on the Certified Material Test Report is also listed.
- Quality Levels and Process Control: Introduced the PSL2 option and its corresponding annex requirements. Details such as conditions for certifying dual slope hubs, requiring customer approval for weld repair, and ensuring test coupons represent finished flanges reflect a shift from “conforming to standards” to “verifiable quality”.
- Expanded Size Coverage: Added NPS 22 Class 900, responding to market demand for high-pressure large diameter piping.
ASTM A988-26: Standardized Recognition of Hot Isostatic Pressing Technology
This new standard, published in February 2026, establishes the first unified specification framework for Hot Isostatic-Pressed stainless steel flanges:
- Powder Metallurgy Process: The standard defines the manufacturing process for HIP flanges—loading prealloyed powder into a can, evacuating, sealing, and consolidating via high-temperature isostatic pressing. This method eliminates the anisotropy and segregation found in traditional forgings, achieving near 100% material density.
- Expanded Material Grades: Covers multiple grades including martensitic, austenitic, age-hardening, and austenitic-ferritic duplex stainless steels, offering more options for high-temperature pressure applications.
- Performance Validation Requirements: Specifies density testing, hydrostatic tests, ultrasonic examination, and mechanical property requirements (tensile, yield, elongation, hardness) to ensure the structural integrity of HIP components.
For procurement professionals, understanding the logic behind these standard updates is essential for selecting compliant suppliers and mitigating technical risks. The “traceability” emphasized by MSS SP-44-2026 and the “advanced manufacturing” represented by ASTM A988-26 are redefining the quality boundaries of flanges.
All data are sourced from publicly available sources and are provided for learning, communication, and reference purposes only. If there are any errors, please contact for correction. Please make your own judgment, this website assumes no responsibility.