For most people, the difference between steel pipe and steel tube is often unclear. For example,you,the reader of the artical,also belong to the “most people”,right ? They’re hollow cylinders, therefore many people like you have the common thinks that these two words have the same meaning. That’s exactly wrong！Now let me tell you something and I’m sure you’ll have some new ideas.
Step one: main difference
1. The pipe is vessel – the tube is structural
As we all know, vessels are containers that can store things, such as bowls, buckets and pots. They all have one thing in common, that is one side is open and the other is closed. Then the tube is clear, it is the channel with both ends open.
2. The pipe is measured by ID – the tube is measured by OD
As shown in the picture above，the OD is the outside diameter, the ID is the inside diameter and the WT is the wall thickness. These three important dimensions has a very simple equation you can read: OD = ID + 2 *WT.
Step two: detail distinction
Steel pipe is usually used for transporting gases and fluids, thus it’s very important to know the capacity of the pipe. The internal cross-sectional area (defined by the id) is vital. It’s not surprising that pipes are specified by id. It’s common to identify pipes in inches by NPS(Nominal Pipe Size). The metric equivalent is called DN (diameter nominal). The metric identification conform to International Standards Organization (ISO). It also applies to all plumbing, natural gas, civil fuel oil, and miscellaneous piping for buildings.
Steel tube is mostly needed by structures,thus the od is the important data. The strength of steel tube depends on the wt. Hence the steel tube is specified by the od and the wt. Steel tube is also not only supplied in round sections but can be formed into square and rectangular tube. There are two different mother tube of each square or rectangular steel tube. It is meaning that they are formed from the original round tube. The round tube will pass through a forming and a sizing section on the tube mill. During the same process it will continue through a couple of sets of turks and it will form the round tube to a square or a rectangular steel section.
A plumber always says that the id on the pipe label is only a *nominal* id. For example, a (nominal) 1/8 wrought steel pipe will typically have a *measured* id of 0.269 (schedule 40) or 0.215 (schedule 80).
Step three: more details
Steel tube used in structural would most likely be seam welded while pipe is normally a seamless steel product. Some steel tubes are seam welded,because they are used for transporting fluids. These steel tubes for water pipes and welded tubes are commonly used in the agricultural industry for manufacturing pivots. If the pipe is sealed at both ends and the water is pumped to a certain pressure level, the tube will undergo a process called stress testing. This will quickly indicate whether there are leaks or bad points in the weld of the circular hollow section being tested.
Step four: about us
SHANDONG WAN STEEL Import and Export Co., a professional steel pipe supplier in China. We have a lot of large domestic and foreign partners. Our production base include Shandong , Jiangsu,Tianjin , Foshan,ect. Seamless steel pipe, spiral steel pipe, welded steel pipe, hot dipped galvanized steel pipe, precision alloy seamless steel pipe and stainless steel seamless pipe are some main products of company. Moreover,we have all kinds of pipesin large inventory at all times. It is said that we can meet your individual requirements in both of quantity and quality. If you have any needs,please contact our professional customer service personnel.