Some times we say steel tubes, and some times we say steel pipes, do you know the difference between Tube and Pipe?
Here are 7 points to help us distinguish between the tube and pipe：

1. Different shapes: tubes have square, rectangular, and round tubes: pipes are all round.
2. Different toughness: tube is rigid, but also copper and brass; pipe is rigid and resistant to bending;
3. Different classification methods: tube according to outer diameter and wall thickness; pipe according to wall thickness code (pipe schedule and nominal diameter) European standard = national pipe size American standard.
4. The use condition is different: tube is used for small diameter, generally 1/16” to 2” (3mm-50mm) 10-inch tube is rare; pipe is used for large diameter, from 1/8” to 80” All have. 

    

5. The requirements are different: tube pays attention to the accuracy of the outer diameter, because it involves pressure, it is used for cooler tube, heat exchanger tube, boiler tube; pipe pays attention to the wall thickness, because the pipe mainly transports liquid, it requires high internal pressure capacity ;
6. The relationship between the wall thickness grade and the wall thickness is different: the wall thickness grade of the tube is increased by one level, and the wall thickness is increased by 1-2mm, and the increase is fixed; while the wall thickness of the pipe is represented by schedule, and the relationship between the values of each grade is uncertain. For example, the wall thickness of Sch.20 is about 1.245mm, while the wall thickness of Sch.30 is about 1.448mm, and the wall thickness of Sch.40 is indeed 1.727mm, and the increase is inconsistent, because Sch is actually (design pressure/design temperature allowable stress ) X1000
7. The connection methods are different: the tube can be connected quickly, and the connection is not difficult. It can be flared, brazed, or coupled; the connection of the pipe is labor-intensive, and it can be welded or screwed. , you can also use flange connection;