Flange Marking refers to the identification markings stamped on a flange surface. These markings specify important technical information such as material grade, pressure class, size, and manufacturing standard.
Understanding flange marking is essential for engineers, procurement teams, and maintenance technicians to ensure the correct flange is selected for piping systems used in water, steam, oil, gas, and industrial process applications.
Common Information Found in Flange Markings
1. Material Grade
This identifies the metal type and mechanical properties of the flange. Common examples include:
- SS400 – Carbon structural steel
- A105 – Forged carbon steel for pressure applications
- SS304 / SS316L – Stainless steel for corrosion resistance
2. Pressure Rating
Pressure rating indicates the maximum allowable working pressure of the flange:
- JIS: 5K, 10K, 20K
- ANSI: Class 150, 300, 600
- DIN/EN: PN10, PN16, PN40
3. Flange Size
Flange size is typically marked in inches or DN (Diameter Nominal):
- 6 inch flange
- DN150 flange
The flange size must match connected pipes, valves, and fittings to ensure proper installation.
4. Flange Standard
This identifies the dimensional specification used during manufacturing:
- ANSI B16.5
- JIS B2220
- DIN EN1092-1
Sometimes markings only show the pressure class such as 10K or Class 150 when the governing standard is already known.
5. Manufacturer Identification
Manufacturer name or logo markings help verify product origin and ensure traceability for industrial projects.
6. Heat Number / Lot Number
Heat numbers allow full material traceability and are critical for quality assurance, inspection, and project documentation.
Why Understanding Flange Marking is Important
- Prevents incorrect flange selection
- Improves piping system safety
- Supports technical inspection processes
- Ensures compliance with engineering specifications
- Helps procurement teams verify correct materials
About S.K. Fitting Valve
S.K. Fitting Valve is a supplier of industrial flanges, pipe fittings, valves, and piping equipment for industrial applications. We supply Carbon Steel, Stainless Steel, and Alloy Steel flanges manufactured to international standards including ANSI, JIS, and DIN.
Our team provides support to help customers select the correct flange specifications for their projects.
