DN, or "Nominal Diameter," refers to the nominal size of a pipe's internal diameter, represented in millimeters. This measurement is crucial for ensuring that pipes and fittings are compatible when connected, making it essential for both installation and operational efficiency.

Common DN Sizes in Steel Tubes

Steel tubes come in various DN sizes, each specifically designed for different purposes. Typically, the DN sizes range from DN15 to DN1200, with each size corresponding to a specific internal diameter. Below is a list of some of the most common DN sizes along with their respective nominal diameters in millimeters:

- **DN15:** 21.3 mm

- **DN20:** 26.7 mm

- **DN25:** 33.4 mm

- **DN32:** 42.2 mm

- **DN40:** 48.3 mm

- **DN50:** 60.3 mm

- **DN65:** 73 mm

- **DN80:** 88.9 mm

- **DN100:** 114.3 mm

DN, or nominal diameter, is a fundamental concept in the realm of steel tubes that signifies the nominal internal diameter of a pipe. With various DN sizes available, it is essential to understand your project's requirements to select the appropriate steel tubes that ensure compatibility, accuracy, and efficiency.