Schedule 40 Carbon Steel Pipe

How to select the parameters in the purchase order?

In the process of steel pipe procurement, do you often encounter such purchase orders: "DN100, wall thickness 10mm, Q355B"? This string of letters and numbers is really a headache at first glance, and I don't know where to start. In fact, as long as you understand the meaning of these parameters, it will be easy to buy steel pipes. As an employee of Hebei Huayang Steel Pipe Co., Ltd., today I will explain these parameters in detail for you, so that you can easily get the steel pipe purchase.

Nominal diameter: "invisible code" behind DN

"DN" is one of the most frequently encountered parameters in steel pipe procurement, which represents the nominal diameter of steel pipe. Many people will confuse the nominal diameter with the actual outer diameter of steel pipe, but there is an essential difference between them. Nominal diameter is a standard diameter artificially specified for the convenience of pipeline design, manufacture, installation and maintenance. It is neither the outer diameter nor the inner diameter of steel pipe, but a standardized value related to pipeline system. ​

Take DN100 as an example, the actual outer diameter of the corresponding steel pipe is 114 mm.. This is determined through long-term practice and industry norms, and the purpose is to ensure that steel pipes produced by different manufacturers can match each other and facilitate connection. If DN100 is purchased as a steel pipe with an outer diameter of 100mm, the purchased steel pipe may not be able to connect with the existing pipeline interface, which will not only delay the progress of the project, but also cause unnecessary losses. ​

Different nominal diameters correspond to different actual outer diameters, which has a set of strict industry standards. For example, the actual outer diameter corresponding to DN50 is 57mm, and the actual outer diameter corresponding to DN200 is 219mm, etc. In the production process, we strictly follow these standards to ensure that each batch of steel pipes can meet the size requirements corresponding to the nominal diameter, so that customers have no worries in the procurement and use process.