What Is a Coated Tube? — Focus on Enamel-Coated Tubes for Corrosive Gas Applications

1. Overview of Coated Tubes

A coated tube refers to a metal tube whose surface has been treated with a specialized coating layer to improve corrosion resistance, fouling resistance, and thermal durability. Among the various types of coated tubes, the enamel-coated tube (also known as glass-lined steel tube) is particularly valued for harsh gas environments due to its excellent anti-corrosion and anti-adhesion performance.

2. What Is an Enamel-Coated Tube?

An enamel-coated tube is manufactured by firing a layer of inorganic glass enamel onto a carbon steel base tube at high temperatures (800°C+). The result is a composite structure that combines the strength of steel with the chemical inertness and smoothness of glass.

This type of coated tube is especially effective in heat exchanger systems where aggressive chemical components, tar, or dust are present.

3. Industrial Applications

Enamel-coated tubes are widely used in:

• Coke Oven Gas Cooling (Primary Coolers)

• Chemical Gas Heat Recovery Systems

• Waste Heat Boilers in Iron & Steel Plants

• Chloride-Rich Flue Gas Applications (e.g., Waste Incineration, FGD systems)

• Sulfur- or Tar-Laden Gas Heat Exchange

4. Key Features and Benefits