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How to Distinguish Black Steel Pipe and Galvanized Steel Pipe?

Black steel pipe and galvanized steel pipe have several respects similar to each other, such as they are common kind of pipe applied to transport liquid and gas, so there are many people can't distinguish them clearly.


The main difference between black steel pipe and galvanized steel pipe:


Black steel pipe and galvanized pipe all use steel as raw material. And general speaking, galvanized steel pipe is more expensive and more durable since galvanized pipe has a zinc coating while black pipe does not. Galvanized pipe covered with a layer of zinc which makes it have higher ability of corrosion protection and help to prevent the accumulation of mineral deposits that will block the pipe.This will lead to a burst. So galvanized steel pipe is more suitable for carrying water instead of gas.


For transportation, galvanized pipe is mainly used for carrying water to supply home and commercial buildings. It is also serve as scaffolding frames because of its rust prevention. Black steel pipe is manufactured as seamless which makes it a better type for gas transportation. It can be used for fire sprinkler system since it can prevent fire better than galvanized pipe. Since it has a dark color surface that is form by iron oxide during the manufacturing process, it is called black steel pipe. The main difference between steel pipe and galvanized pipe lies in the surface. Black steel pipe is uncoated and made without steam, and therefore, it is widely used for transporting gas like propane and natural gas to residential and commercial building. Black steel pipe is more easily to corrosion than galvanized pipe, so it is more suitable for transporting gas. black steel pipe is not suitable for water transport. Black steel pipes are tending to corrode in water and mineral of the pipe will dissolve into the water and clog the line as well.


How to differentiate this two pipe?


1. Examine the color of the pipe. Black steel pipe is flat black and galvanized pipe is silver and gray. Black steel pipe is darker than galvanized pipe.
2. Tell the difference by the material they carry. galvanized pipe is usually applied for water carriage, black steel pipe for gas deliver.
3. Tell from the year the pipe being used. If the pipe is installed after 1950s, it’s likely to be black steel since black steel pipe used later than galvanized pipe.