Spiral steel pipe wall thickness allowable error standard

Definition of spiral steel pipe wall thickness:

Spiral steel pipe, also called spiral welded pipe, is a spiral pipe made of steel plate or steel strip through a certain processing technology. The wall thickness of spiral steel pipe refers to the average wall thickness of the cross-section of the steel pipe. The spiral welded pipe adopts the advanced double-sided submerged arc welding process, which can achieve welding at the best position. It is not prone to defects such as wrong edges, welding deviation and incomplete penetration, and it is easy to control the welding quality.

The wall thickness of spiral welded steel pipes DN (nominal diameter) 250 is generally what the industry calls 273. The thickness of welded steel pipes (spiral steel pipes) is generally between 6-8mm. The national standards for spiral steel pipe wall thickness are roughly divided into 8 types:
1. Wall thickness of 6-8mm is the standard specification of 219, 273 and 325 spiral steel pipes;
2. 6-10mm, which is the standard specification of 377, 478 and 529 spiral steel pipes;
3. 6-12mm, which is the standard specification of 720 spiral steel pipe;
4. 8-12mm, which is the standard specification of 920 spiral steel pipe;
5. 9-13mm, which is the standard specification of 1220 spiral steel pipe;
6. 10/14mm, which is the standard specification of 1420 spiral steel pipe;
7. 12/14mm is the standard specification of 1620 spiral steel pipe.
8. 14mm, which is the standard specification of 1820, 2020 and 2220 spiral steel pipes.

Spiral steel pipe wall thickness allowable error standard:
According to relevant national standards, the allowable error in wall thickness of spiral steel pipes should meet the following standards:
1. When the wall thickness of spiral steel pipe is ≤10mm, the allowable error is ±0.5mm;
2. When the wall thickness of spiral steel pipe is >10mm, the allowable error is ±5% of the wall thickness.

The required deviation range for diameters below 508 is 12.5% up and down
Spiral steel pipes with diameters above 508 are 10% higher and lower

It should be noted that the above standards only apply to spiral steel pipes with a nominal inner diameter below 508mm. For spiral steel pipes with an inner diameter greater than 508mm, the allowable error in wall thickness should be determined in accordance with relevant standards.

The importance of the allowable error in wall thickness of spiral steel pipes:

The wall thickness of spiral steel pipes is one of the important indicators of steel pipe quality. It not only affects the load-bearing capacity and service life of spiral steel pipes, but is also directly related to the production process and quality control of the pipes. Therefore, formulating a reasonable allowable error standard for wall thickness is of great significance to ensure the quality and use effect of spiral steel pipes.

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