Introduction
ASME B16.5 is the American standard that covers pipe flanges and flanged fittings ranging from NPS ½ through NPS 24. It specifies the dimensions, pressure–temperature ratings, tolerances, materials, marking, and testing requirements for flanges commonly used in piping systems.
Flange types included: Welding Neck, Slip-On, Socket Weld, Threaded, Lap Joint, and Blind flanges.
Pressure classes: 150, 300, 400, 600, 900, 1500, and 2500.
Scope: The standard applies to both forged flanges and flanged fittings, ensuring dimensional uniformity and interchangeability.
Materials: Covers a wide range of ferrous and non-ferrous alloys, including carbon steel, stainless steel, alloy steel, and nickel alloys.
Tolerances: Strictly defines tolerances for flange thickness, bolt circle, bolt holes, and raised face height, ensuring safe and reliable connections.
This standard is widely adopted in industries such as oil & gas, chemical, power generation, shipbuilding, and water treatment, providing a unified specification for design, manufacturing, and inspection of flanges.
































Have You Any Question?
What to do if Mixed Materials are found in the project?
When materials get mixed up, it’s like building a Lego set with wrong pieces eventually everything falls apart.
The only viable solution requires 100% PMI testing on every individual flange using calibrated XRF analyzers, eliminating material certification risks through a certified processes.
Every factory out there claims they check their flanges with those XRF guns Piece by Piece. In all of Tsingshan Group’s backyard, only 3 manufacturers actually full-test every piece. We’re one of them.
Why Small Foundries happen the mix-ups?
These monster forging machines won’t start unless you order over 15 tons , like buying 100 pens when you need 10 . Factories have to mash together different steel batches.
Keeping materials separate costs small foundries 28% extra, like trying to sort Legos with a toddler wrecking them daily.
6/10 suppliers can’t track materials properly, it’s shipping mystery boxes that’ll bite us when things go wrong.
What is the standard lead time for orders? How do you handle delays caused by emergencies (e.g., pandemics, logistics disruptions)?
The standard lead time is 1 week, adjusted based on product complexity and order volume.
For unexpected risks, we implement the following measures:
—-Maintain backup suppliers and diversified logistics channels.
—-Monitor supply chain status in real time and provide early warnings to customers.
—-Prioritize critical orders and offer expedited service options.
What specific quality control steps are implemented during production?
Three-tier QC system:
—-Incoming Quality Control (IQC): Verify raw material specifications and certifications.
—-In-Process Quality Control (IPQC): Sample-test key parameters at each production stage.
—-Outgoing Quality Control (OQC): 100% visual/functional inspection, packaging checks, and destructive testing on samples.
—-Use SPC (Statistical Process Control) and automated inspection tools to ensure consistency.
How do you continuously improve product quality and on-time delivery rates?
Data-driven approach: Monthly analysis of customer complaints, return rates, and delivery performance.
PDCA Cycle (Plan-Do-Check-Act): Implement process upgrades or supplier training based on findings.
Closed-loop feedback: Regularly survey customer satisfaction and integrate results into KPI evaluations.
Intended Use: Suitable for supplier manuals, contract annexes, official websites, or sales communication to enhance client trust and reduce collaboration friction.
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