How to distinguish black steel pipe from seamless galvanized pipe

Posted by zora li on August 22nd, 2023

How to distinguish black steel pipe from seamless galvanized pipe

Black steel pipe is uncoated steel, also known as black steel. The dark color comes from iron oxides that form on its surface during the manufacturing process. When steel pipe is forged, a black oxide scale forms on its surface, giving it the finish seen on this type of pipe.

Galvanized steel pipe is steel covered with a layer of zinc metal. During galvanizing, steel is dipped into a bath of molten zinc, ensuring a strong, uniform barrier coating. Galvanized pipe is covered with a zinc material that makes the steel pipe more resistant to corrosion.

A brief description of the differences

· Both black and galvanized pipes are made of steel.
· While galvanized pipe has a zinc coating, black pipe does not
· Due to its tendency to corrode, black pipe is more suitable for carrying gas. On the other hand, galvanized pipe is ideal for carrying water, but not for carrying gas
Galvanized pipe is more expensive due to galvanization
· Galvanized pipe is more durable

The primary use of black steel pipe is to deliver propane or natural gas into residential and commercial buildings. The pipe has no seams making it a better pipe for carrying gas. Black steel pipe is also used in fire sprinkler systems because it is more fire resistant than galvanized pipe. The primary use of galvanized pipe is to convey water to homes and commercial buildings. Zinc also prevents mineral deposits from building up that can clog water pipes. Galvanized pipe is often used as scaffolding because of its corrosion resistance.

Question difference
The zinc on galvanized pipe can flake off over time, clogging the pipe. Flaking can cause the pipe to burst. The use of galvanized pipes to carry gas presents a hazard. On the other hand, black steel pipes corrode more easily than galvanized pipes and allow minerals from the water to build up in them.

Cost difference
Galvanized line pipe costs more than black steel pipe because of the zinc coating and manufacturing process involved in producing galvanized pipe. Galvanized fittings also cost more than black steel fittings. Galvanized steel pipe should never be joined to black steel pipe during the construction of a residential or commercial building.

How to distinguish between these two pipelines?

1. Check the color of the pipe. Black steel pipe is flat black and galvanized pipe is silver gray. Black steel pipe is darker than galvanized pipe.
2. To distinguish the difference by the material they carry. Galvanized pipes are usually used for water transportation, and black steel pipes are used for gas transmission.
3. If the pipe was installed after the 1950s, it is likely to be black steel, as black steel pipe was used later than galvanized pipe