What is the surface roughness of stainless steel precision tubes

Stainless steel precision tubes are called precision tubes because they have high precision, good tolerance control range, uniform wall thickness, smooth inner wall, no lines, and smoother surface roughness than ordinary tubes.

1. Definition of surface roughness
First of all, let's understand what surface roughness is. Surface roughness refers to the unevenness of small spacing and tiny peaks and valleys on the processed surface. The distance (wave distance) between the two peaks or two valleys is very small (less than 1mm), which belongs to the microscopic geometric shape error. The smaller the surface roughness, the smoother the surface.

2. Surface roughness of precision tubes
If it is a stainless steel precision tube after cold rolling, it has not been polished and ground. Generally, the roughness of the outer surface is: Ra≤0.6μm, and the roughness of the inner surface is: Ra≤0.8μm. Of course, there are also some manufacturers or customers who have relatively high requirements for stainless steel pipes, requiring the roughness of the outer surface to be: Ra≤0.4μm, and the roughness of the inner surface to be: Ra≤0.6μm, which requires fine polishing of the inner and outer surfaces. If the wall thickness of the precision stainless steel pipe is thicker than 4mm and the inner diameter is less than 10mm, the roughness of the inner hole is slightly worse and is Ra≤1μm.

3. The influence of surface roughness on pipes
(1) Affects wear resistance. The rougher the surface, the smaller the effective contact area between the mating surfaces, the greater the pressure, the greater the friction resistance, and the faster the wear.
(2) Affects fatigue strength. There are large troughs on the surface of rough stainless steel products. Like sharp notches and cracks, they are very sensitive to stress concentration, thus affecting fatigue strength.
(3) Affects corrosion resistance. The rough surface makes it easy for corrosive gases or liquids to penetrate the metal inner layer through the microscopic valleys on the surface, causing surface corrosion.
(4) Affects sealing. Rough surfaces cannot fit tightly together, and gas or liquid leaks through the gaps between the contact surfaces.
(5) Affecting measurement accuracy. The surface roughness of the measured surface of the pipe and the measuring surface of the measuring tool will directly affect the measurement accuracy, especially in precision measurement.

In addition, surface roughness will have varying degrees of influence on the coating, thermal conductivity, resistance to liquid and gas flow, etc. of precision stainless steel pipes.

The above is the content of the surface roughness of stainless steel precision pipes. Through the above introduction, we understand what surface roughness is, customer requirements for the surface roughness of precision pipes, and the impact of surface roughness on pipes. The inner surface roughness of stainless steel precision pipes is a standard for measuring the quality of pipes. The lower the roughness, the lower the possibility of particle carrying.