Flange marking refers to the information stamped or engraved on a flange to identify its specifications. These markings allow engineers, buyers, and technicians to select the correct flange for piping systems and ensure compliance with industrial standards.

Correct interpretation of flange markings helps reduce installation errors, improves system safety, and supports quality control in industrial applications.

Common Information Found in Flange Markings

1. Material Grade
Indicates the material and mechanical properties of the flange, such as:
  - SS400
  - A105
  - SS304 / SS316L

2. Pressure Rating
Defines the maximum pressure the flange can handle, for example:
  - 5K / 10K / 20K (JIS)
  - Class 150 / 300 (ANSI)
  - PN10 / PN16 (DIN / EN)

3. Flange Size
Specified in inches or metric units, such as:
  - 6 inch
  - DN150

4. Flange Standard
Identifies the dimensional and drilling standard of the flange, including:
  - ANSI B16.5
  - JIS
  - DIN

5. Manufacturer Identification
A name or symbol used to identify the manufacturer and verify product origin.

6. Heat Number / Lot Number
Used for quality control and material traceability, especially in industrial and project-based applications.

Why Understanding Flange Markings Matters