What is the absolute roughness of API 5L X52 pipe?

The following are some of the main aspects:
Production process
Rolling method: If it is a seamless steel pipe, during the perforation and rolling process, the surface roughness of the roller, the rolling speed, the rolling pressure, etc. will affect the roughness of the inner surface of the pipe. For example, when high-precision rollers are used and the rolling process is precisely controlled, the absolute roughness of the inner surface of the pipe may be around 10-20μm; while the pipe produced by ordinary rolling process may have an absolute roughness of 30-50μm.
Welding process: For welded steel pipes, welding methods and welding parameters have a great influence on the roughness of the weld and heat-affected zone. For high-frequency resistance welded steel pipes, the absolute roughness of the weld is generally 20-30μm; for submerged arc welded steel pipes, the absolute roughness of the weld may be around 30-50μm, and the roughness of the heat-affected zone will also increase.
Surface treatment
Pickling: Pickling is mainly to remove impurities such as scale and rust on the surface of the pipe. Generally, it will not significantly change the original roughness of the pipe. However, if the pickling is excessive or the cleaning is not thorough after pickling, it may cause slight corrosion on the surface of the pipe, which will slightly increase the roughness, which may increase by about 2-5μm.
Galvanizing: The thickness and uniformity of the galvanized layer will affect the overall roughness of the pipe. Generally, the thickness of the hot-dip galvanized layer is about 50-100μm, which will increase the surface roughness of the pipe, and the increase may be 10-20μm.
Painting: The surface roughness of the pipe after painting depends on the thickness of the paint layer and the coating quality. Generally speaking, the thickness of the paint layer is 30-80μm, which will increase the surface roughness of the pipe by 5-15μm.
Use environment
Corrosion: After being used in some corrosive media for a period of time, the surface of the pipe will corrode, forming corrosion pits, etc., thereby increasing the surface roughness. For example, the surface roughness of X52 pipes used in an environment containing acidic media such as hydrogen sulfide may increase from the initial 20-30μm to 50-100μm or even higher after 1-2 years of use.
Scaling: If the transported medium contains impurities or substances that are prone to scaling, a scale layer will form on the inner wall of the pipe, which will also increase the roughness. For example, for X52 pipes that transport water containing a certain amount of sediment, the roughness will increase significantly over time when the scale thickness on the inner wall reaches 1-2mm.

API 5L X52 PSL1 Pipe Absolute Roughness