Table of content
Introduction
Both black pipe and galvanized steel pipe are commonly used steel pipes, and both can be used in industrial pipelines or structural engineering. Both are made of steel or iron. The surface of galvanized pipe is coated with zinc, and black pipe is only coated with anti-rust oil after production. In addition to this difference, the two also have different production processes and different application environments. We will introduce these two products.
What Are Black Pipe Fittings?
Black pipes can be produced from cast iron or low-carbon steel as raw materials. Black pipes are usually only coated with anti-rust oil, and their appearance is dark black. Its anti-corrosion effect is general because it is not often used in highly corrosive environments.
Key characteristics:
- No coating
- The color is mostly matte black or dark gray
- Mostly end threaded
- Poor corrosion resistance
Common uses:
- Furniture brackets
- Natural gas pipelines
- Fire protection pipelines
What Are Galvanized Pipe Fittings?
Galvanized pipes are usually made of carbon or steel, and then a layer of galvanized layer is added to its surface through a hot-dip galvanizing process to achieve a corrosion-resistant effect. The principle is that zinc has strong corrosion resistance. Because this steel pipe is suitable for some highly corrosive environments.
Key characteristics:
- The galvanized layer on the surface makes it mostly silver-gray in color
- Corrosion-resistant
- Can be threaded for easy assembly
Common uses:
- Water treatment system
- Outdoor piping system
- Fences and frames, etc.
Black vs Galvanized: Key Differences
| Feature | Black Pipe Fittings | Galvanized Pipe Fittings |
|---|---|---|
| Coating | No coating | Zinc-coated |
| Color | Black or dark gray | Silver or dull gray |
| Corrosion resistance | Low | High |
| Suitable for gas lines | Yes | No (zinc flakes risk blockage) |
| Suitable for water | No (prone to rust) | Yes (resists corrosion) |
| Weight | Lighter | Slightly heavier |
| Cost | Typically lower | Slightly higher |
| Code compliance | Approved for gas use | Often prohibited for gas lines |
Why You Shouldn’t Mix the Two
Black pipes and galvanized pipes cannot be mixed. Especially in gas pipelines, galvanized pipes may lose zinc after long-term use, which is easy to cause blockage in gas pipelines. Moreover, different materials will cause electrochemical corrosion under the action of some transport objects, resulting in installation failures.
Safety and Code Considerations
For gas lines
- Gas pipelines mostly use black pipes and basically do not use galvanized pipes
- The zinc shedding of galvanized pipes will cause safety hazards
- If it must be used, please be sure to use it according to the requirements of the local gas company.
For water systems
- Both steel pipes can be used
- Galvanized pipes are more corrosion-resistant in some humid environments.
- Black pipes are mostly used for drinking water
How to Identify Each Type
The following methods can be used to identify the two types of steel pipes:
1. Look at the color: black pipes are mostly black, and galvanized pipes are mostly silver-gray.
2. Look at the texture: the surface of black pipes is rough and matte, and the surface of galvanized pipes is smooth and shiny
3. Look at the label: Generally, steel pipes are marked with production numbers and product names
Summary
In addition to the different surfaces, black pipes and galvanized pipes also have different application environments. The above article introduces the differences between the two in detail. Now it is summarized as follows:
- Black pipes: mostly used for gas, steam or indoor pipeline systems.
- Galvanized pipes: mostly used in outdoor environments with high corrosion.
Cannot be mixed.
