Designation of pipeline grade
Thread Content
The pipe grade number is composed of the following three units: For example, in N2B, the first unit is N, which indicates the nominal pressure of the pipe; the second unit, 2, represents the sequence number, which is expressed as an Arabic digit starting from 1; the third unit, B, indicates the category of the pipe material. I don’t understand how the second unit is determined – is it the sequence number of pipes with the same material and nominal pressure? Which senior can give an example?
This is the standard for chemical labeling; the sequence number refers to different series of the same material at varying temperatures. The grade of pipeline material is the result of the combined effects of temperature and pressure.
Generally, the grade numbers of pipeline materials are not uniform. Each engineering company receives the design institute’s information in a different format. Uniform process specifications will always provide explanations for the representation methods.
Simply put, as temperature and pressure change, the allowable stress of the material also changes. For example, when the design pressure is 1.0 MPa and the other design temperatures are 150 degrees and 300 degrees, the material grade chosen for the pipe fittings will vary. Therefore, the material grade tables show several series, as even for the same material and under the same pressure, different design temperatures result in different material choices.
The sequence numbers are assigned based on variations in temperature and pressure. For example, 30 degrees at 0.5 MPa and 150 degrees at 0.5 MPa represent two different operating conditions. In such cases, the pipe material can be chosen to have the same nominal pressure rating and the same material type; it can then be denoted as N1B, N2B, and so on. B denotes carbon steel, which comes in many grades with corresponding manufacturing standards; different grades can be selected depending on the serial number. I’m not sure if the OP will understand with this explanation
Each project has detailed specifications for the pipeline-grade material standards. The requirements for each project vary.