Steel profiled pipe: application, standards, gauge
What are used tubes for? What are the standards and GOST for steel profiled pipe currently in force? What sizes are these products made with? Let's search for answers.
Application
Applications of round and profiled pipes are separated by a number of features of products that directly follow from the shape of their section. The scope of application of round pipes is the transportation of liquids and gases, including those with overpressure.
There are two reasons for this:
- The round shape provides the maximum cross-sectional area and, therefore, the maximum throughput at a fixed circumference.
Note! The greater the girth of the pipe (circumference or perimeter), the greater the price per meter with a fixed wall thickness.
- In addition, the round section provides maximum tensile strength with excessive internal pressure. Notice, this is a direct consequence of the first postulate: the internal environment presses the walls the stronger, the larger their area; the area with a fixed length is minimal just at the round pipe.
Shaped pipes - square and rectangular are used where maximum rigidity with minimum weight is needed. What is the relationship between sectional profile and stiffness?
Let me explain with the example of a small experiment from a Soviet-era terry school course that is easy to do with your own hands.
- We will assemble from a thin slat on four studs a rectangular frame to fit A4 paper. It is not difficult to guess that the frame laid on the table, when a small force is applied in the horizontal plane, will easily turn into a rhombus with arbitrary angles.
- And now we paste on the frame a paper sheet and after the glue dries, we will try again to turn the rectangle into a rhombus. Hint: applying the effort possible on an adult in the same plane will not succeed.
In the proftrub wall, parallel to the direction of bending, play the role of the notorious paper sheet. They do not allow to bend the pipe, despite its own small thickness and dimensions: steel is still much stronger than paper by tearing.
Scopes of a proftruba are very numerous.
Here are some examples:
- Bearing beams and racks of metal structures.
- Racks and railings handrails.
- Frameworks of greenhouses and sheds from pipes.
Regulations
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There are three main documents regulating the production of products interesting to us.
- GOST 13663-86 for steel shaped pipes contains technical requirements for production.
- The range of square-shaped steel tubes is contained in the standard number 8639-82.
- The range of rectangular pipes is taken according to GOST 8645-68.
It is curious: in spite of other technical requirements for production, in terms of size, a stainless steel profile pipe is produced according to the same standards as a pipe made of non-corrosive steels - GOST 8639-82 and 8645-68.
Let's take a look at the content of the documents.
Technical conditions
According to the document, the pipework can be done in four ways:
| Production technology | Short description |
| Hot rolled | The cylindrical billet is heated above the recrystallization temperature and stitched, turning into a hollow cylinder. Then she rolls in a hot condition on the mandrel, acquiring the desired shape. |
| Cold-formed | The stitched workpiece is cooled, after which it undergoes deformation and calibration. |
| Electrowelded | The flat strip is rolled into a square or rectangle, then the longitudinal seam is boiled with high-frequency currents or an electric arc. |
| Cold welded electric | The flat strip is welded into a round tube, which is deformed by rollers. |
Products can be standardized by the chemical composition of steel or mechanical properties.
The presence of cracks, sunsets and flaws on the surface of pipes is not allowed; only minor dents and scratches that do not extend the pipe beyond the maximum tolerances are allowed. The remainder of the burr (a convex weld) is allowed on the inner side of the electric-welded pipe.
In the process of testing, measurements and testing are carried out:
- Outer dimensions.
- Wall thickness
- Concavity.
- Length.
- Curvature.
- Twisting.
- The ability to withstand stretching and, in some cases, hydraulic pressure.
- Chemical composition.
Instructions for conducting the tests themselves in GOST absent; however, it contains references to other standards where the relevant methodologies are specified.
Assortment
GOST 8639-82
So, what can be the dimensions of steel square tubes:
| Outer size, mm | Wall thickness mm |
| ten | 1.0 |
| 15 | 1.0; 1.5 |
| 20 | 1.0; 1.5; 2.0 |
| 25 | 1.0; 1.5; 2.0; 2.5; 3.0 |
| thirty | 2.0, 2.5; 3.0; 3.5; 4.0 |
| 35 | 2.0; 2.5; 3.0; 3.5; 4.0; 5.0 |
| 40 | 2.0; 2.5; 3.0; 3.5; 4.0; 5.0; 6.0 |
| 42 | 3.0; 3.5; 4.0; 5.0; 6.0 |
| 45 | 3.0; 3.5; 4.0; 5.0; 6.0; 7.0; 8.0 |
| 50 | 3.0; 3.5; 4.0; 5.0; 6.0; 7.0; 8.0 |
| 60 | 3.5; 4.0; 5.0; 6.0; 7.0; 8.0 |
| 70 | 4.0; 5.0; 6.0; 7.0; 8.0 |
| 80 | 4.0; 5.0; 6.0; 7.0; 8.0 |
| 90 | 5.0; 6.0; 7.0; 8.0 |
| 100 | 6.0; 7.0; 8.0; 9.0 |
| 110 | 6.0; 7.0; 8.0; 9.0 |
| 120 | 6.0; 7.0; 8.0; 9.0 |
| 140 | 6.0; 7.0; 8.0; 9.0 |
| 150 | 7.0; 8.0; 9.0; 10.0 |
| 180 | 8.0; 9.0; 10.0; 12.0; 14.0 |
GOST 8645-68
- The minimum standard size stipulated by the standard is 10x15 mm with a wall thickness of 1.0, 1.5 and 2.0 mm. The maximum is 180x150 mm with walls of 8.0, 9.0, 10.0 and 12.0 mm.
- The standard provides for the production of pipes of special sizes - from 28x25 to 230x100 mm. The maximum wall thickness can reach an impressive 20 millimeters.
Conclusion
We hope that the reader is not tired of the abundance of dry numbers, and the material offered to his attention will be useful. As always, additional thematic information can be found in the video in this article. Successes!