Roughness of carbon steel pipe

The roughness of carbon steel pipe depends on the smoothness of its surface. Common roughnesses include Ra, Rz and Rmax, generally between Ra 1.6-6.3 microns.

Concept and measurement method of roughness of carbon steel pipe

The roughness of carbon steel pipe refers to the irregularity and density of the pipe surface. The roughness directly affects the overall surface quality and service life of the pipe. The roughness of carbon steel pipe can be determined by measuring the geometric difference between the pipe surface and a datum. Currently commonly used roughness evaluation indicators include Ra, Rz, Rmax, etc.

Common carbon steel pipe roughness

1.Ra value

The Ra value is the contour area value of the geometric mean line on the surface of the pipe. It is expressed in microns (μm) as a non-directional comprehensive surface roughness index. It is calculated by taking the average distance difference between all points on the surface of the pipe and its corresponding datum plane, which is generally between 1.6-6.3μm.

2. Rz value

The Rz value is the average dispersion between the peaks and valleys of any five adjacent sections along the length of the pipe, expressed in microns. It is measured along the length of the pipe and reflects more of the longitudinal direction of the pipe surface. Uneven conditions. The Rz value of carbon steel pipe is generally between 10-50μm.

3. Rmax value

The Rmax value refers to the groove depth between the largest peak value and the smallest valley value on any short length of the pipe surface. It only considers the maximum irregularity between surfaces in local areas. It is a non-directional indicator. It is usually used to measure the size of protruding defects such as surface depressions, bulges, and burrs, generally between 20-200μm.

The impact of roughness on carbon steel pipe performance

The roughness of carbon steel pipes has a crucial impact on the operating conditions and performance of fluids in the pipeline.

 

1. If the pipe surface is too rough, it will increase resistance to fluid flow, leading to increased turbulence and friction. This will not only reduce pipeline transportation efficiency but also affect the stability of fluid flow.

 

2. If the pipe surface is too smooth, it may also lead to insufficient shear force, which will also affect the fluid's state and flow properties. Therefore, properly controlling the roughness of carbon steel pipes is key to ensuring the normal operation of pipeline fluids.

 

Methods for optimizing carbon steel pipe roughness

To optimize the roughness of carbon steel pipes, a series of effective measures can be taken. For example, galvanizing, polishing, internal coating, and internal lining can be used to improve the surface finish of the pipe. These measures not only improve the compressive strength and corrosion resistance of the pipe, but also effectively reduce the surface roughness of the pipe, reducing the accumulation of scale, sediment, and bacteria. This ensures the stability and safety of pipeline operation and extends the service life of the pipe.

Conclusion

The roughness of carbon steel pipe is an important indicator for evaluating the surface quality of pipes. In general, the smoother the pipe surface and the smaller the roughness, the longer its service life.

Read more: Thermal conductivity of carbon steel pipe